1
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Ke M, Si H, Qi Y, Sun Y, El-Kassaby YA, Wu Z, Li S, Liu K, Yu H, Hu R, Li Y. Characterization of pollen tube development in distant hybridization of Chinese cork oak (Quercus variabilis L.). PLANTA 2023; 258:110. [PMID: 37910223 DOI: 10.1007/s00425-023-04265-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/13/2023] [Indexed: 11/03/2023]
Abstract
MAIN CONCLUSION This work mainly found that the stigma and style of Q. variabilis did not completely lose the specific recognition towards heterologous pollen, a fact which is different from previous studies. Quercus is the foundation species in the Northern Hemisphere, with extreme prevalence for interspecific hybridization. It is not yet entirely understood whether or how the pollen tube-female tissue interaction contributes to the "extensive hybridization" in oaks. Pollen storage conditions correlate with distant hybridization. We conducted hybridization experiments with Q. variabilis as female and Q. variabilis and Q. mongolica as male parents. And the differences in pollen tube (PT) development between intra- and distant interspecific hybridization were studied by fluorescence microscopy and scanning electron microscopy (SEM). Our results showed that -20 °C allowed pollen of both species to maintain some viability. Both Q. variabilis and Q. mongolica pollen germinated profusely on the stigmas. SEM results indicated that in the intraspecific hybridization, Q. variabilis pollen started to germinate at 6 h after pollination (hap), PTs elongated significantly at 12 hap, and entered the stigma at 24 hap. By contrast, Q. mongolica pollen germinated at 15 hap, and the PTs entered the stigma at 27 hap. By fluorescence microscopical studies it was observed that some PTs of Q. variabilis gathered at the style-joining at 96 hap, unlike the Q. mongolica which reached the style junction at 144 hap. The above results indicate that the abundant germination of heterologous pollen (HP) on the stigma and the "Feeble specificity recognition" of the stigma and transmitting tract to HP may create opportunities for the "extensive hybridization" of oaks. This work provides a sexual developmental reference for clarifying the causes of Quercus "extensive hybridization".
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Affiliation(s)
- Meng Ke
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Huayu Si
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yongliang Qi
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yuhan Sun
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Yousry A El-Kassaby
- Department of Forest and Conservation Sciences Faculty of Forestry, The University of British Columbia, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Zhiyong Wu
- Beijing Green Space Maintenance and Management Service Centre, Beijing, 102200, China
| | - Shian Li
- Beijing Green Space Maintenance and Management Service Centre, Beijing, 102200, China
| | - Kelin Liu
- Beijing Green Space Maintenance and Management Service Centre, Beijing, 102200, China
| | - Hai Yu
- Experimental Centre of Forestry in North China, Chinese Academy of Forestry, Beijing, 102399, China
| | - Ruiyang Hu
- Experimental Centre of Forestry in North China, Chinese Academy of Forestry, Beijing, 102399, China
| | - Yun Li
- State Key Laboratory of Tree Genetics and Breeding, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, National Engineering Research Center of Tree Breeding and Ecological Restoration, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
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2
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Satake A, Ohta K, Takeda-Kamiya N, Toyooka K, Kusumi J. Seasonal gene expression signatures of delayed fertilization in Fagaceae. Mol Ecol 2023; 32:4801-4813. [PMID: 37464469 DOI: 10.1111/mec.17079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 06/10/2023] [Accepted: 07/03/2023] [Indexed: 07/20/2023]
Abstract
In the family Fagaceae, fertilization is delayed by several weeks to 1 year after pollination, leading to 1- or 2-year fruiting species depending on whether fruiting occurs in the same or the next year after flowering. To investigate physiological responses underlying the regulation of delayed fertilization, we monitored seasonal changes in genome-wide gene expression in tissues including leaves and buds over 2 years under natural conditions in one- (Quercus glauca) and 2-year fruiting species (Lithocarpus edulis). Genes associated with metabolic changes in response to winter cold, photosynthesis and cell proliferation, which are essential for survival and growth, showed highly conserved seasonal expression profiles between species. However, seasonal expression profiles diverged between species in genes associated with pollination, an important process contributing to the origin and maintenance of the reproductive barrier between plant species. By comparing seasonal progression of ovule development and gene expression in pistillate flowers, we revealed that ovules started developing after winter in the 2-year fruiting species, which could be linked to the activation of genes involved in fertilization and female gametophyte development after winter. These findings suggest that the 2-year fruiting species may have evolved a requirement of winter cold to prevent fertilization before winter and facilitate fertilization and embryo development in the following spring when temperature rises. This study offers new possibilities to explore the evolution of reproductive strategies in Fagaceae.
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Affiliation(s)
- Akiko Satake
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Kayoko Ohta
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Noriko Takeda-Kamiya
- Technology Platform Division, Mass Spectrometry and Microscopy Unit, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Kiminori Toyooka
- Technology Platform Division, Mass Spectrometry and Microscopy Unit, RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Junko Kusumi
- Department of Environmental Changes, Faculty of Social and Cultural Studies, Kyushu University, Fukuoka, Japan
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3
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Ušák D, Haluška S, Pleskot R. Callose synthesis at the center point of plant development-An evolutionary insight. PLANT PHYSIOLOGY 2023; 193:54-69. [PMID: 37165709 DOI: 10.1093/plphys/kiad274] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 04/21/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023]
Abstract
Polar callose deposition into the extracellular matrix is tightly controlled in time and space. Its presence in the cell wall modifies the properties of the surrounding area, which is fundamental for the correct execution of numerous processes such as cell division, male gametophyte development, intercellular transport, or responses to biotic and abiotic stresses. Previous studies have been invaluable in characterizing specific callose synthases (CalSs) during individual cellular processes. However, the complex view of the relationships between a particular CalS and a specific process is still lacking. Here we review the recent proceedings on the role of callose and individual CalSs in cell wall remodelling from an evolutionary perspective and with a particular focus on cytokinesis. We provide a robust phylogenetic analysis of CalS across the plant kingdom, which implies a 3-subfamily distribution of CalS. We also discuss the possible linkage between the evolution of CalSs and their function in specific cell types and processes.
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Affiliation(s)
- David Ušák
- Czech Academy of Sciences, Institute of Experimental Botany, 165 02 Prague, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, 128 44 Prague, Czech Republic
| | - Samuel Haluška
- Czech Academy of Sciences, Institute of Experimental Botany, 165 02 Prague, Czech Republic
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, 128 44 Prague, Czech Republic
| | - Roman Pleskot
- Czech Academy of Sciences, Institute of Experimental Botany, 165 02 Prague, Czech Republic
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4
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Breygina M, Voronkov A, Ivanova T, Babushkina K. Fatty Acid Composition of Dry and Germinating Pollen of Gymnosperm and Angiosperm Plants. Int J Mol Sci 2023; 24:ijms24119717. [PMID: 37298668 DOI: 10.3390/ijms24119717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023] Open
Abstract
A pollen grain is a unique haploid organism characterized by a special composition and structure. The pollen of angiosperms and gymnosperms germinate in fundamentally similar ways, but the latter also have important features, including slow growth rates and lower dependence on female tissues. These features are, to some extent, due to the properties of pollen lipids, which perform a number of functions during germination. Here, we compared the absolute content and the fatty acid (FA) composition of pollen lipids of two species of flowering plants and spruce using GC-MS. The FA composition of spruce pollen differed significantly, including the predominance of saturated and monoene FAs, and a high proportion of very-long-chain FAs (VLCFAs). Significant differences between FAs from integumentary lipids (pollen coat (PC)) and lipids of gametophyte cells were found for lily and tobacco, including a very low unsaturation index of the PC. The proportion of VLCFAs in the integument was several times higher than in gametophyte cells. We found that the absolute content of lipids in lily pollen is almost three times higher than in tobacco and spruce pollen. For the first time, changes in the FA composition were analyzed during pollen germination in gymnosperms and angiosperms. The stimulating effect of H2O2 on spruce germination also led to noticeable changes in the FA content and composition of growing pollen. For tobacco in control and test samples, the FA composition was stable.
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Affiliation(s)
- Maria Breygina
- Department of Plant Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow 119991, Russia
| | - Alexander Voronkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St. 35, Moscow 127276, Russia
| | - Tatiana Ivanova
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St. 35, Moscow 127276, Russia
| | - Ksenia Babushkina
- Department of Plant Physiology, Biological Faculty, Lomonosov Moscow State University, Leninskiye gory 1-12, Moscow 119991, Russia
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5
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Xia Z, Wen B, Shao J, Zhang T, Hu M, Lin L, Zheng Y, Shi Z, Dong X, Song J, Li Y, Wu Y, Yuan Y, Wu J, Chen Q, Chen J. The transcription factor PbrbZIP52 positively affects pear pollen tube longevity by promoting callose synthesis. PLANT PHYSIOLOGY 2023; 191:1734-1750. [PMID: 36617219 PMCID: PMC10022607 DOI: 10.1093/plphys/kiad002] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 12/04/2022] [Indexed: 06/17/2023]
Abstract
In pear (Pyrus bretschneideri), pollen tube growth is critical for the double fertilization associated with seed setting, which in turn affects fruit yield. The normal deposition of callose mediates the polar growth of pollen tubes. However, the mechanism regulating callose synthesis in pollen tubes remains relatively uncharacterized. In this study, we revealed that the typical pear pollen tube lifecycle has a semi-growth duration (GD50) of 16.16 h under in vitro culture conditions. Moreover, callose plugs were deposited throughout the pollen tube lifecycle. The formation of callose plugs was inhibited by 2-deoxy-D-glucose, which also accelerated the senescence of pear pollen tubes. Additionally, PbrCalS1B.1, which encodes a plasma membrane-localized callose synthase, was expressed specifically in pollen tubes and restored the fertility of the Arabidopsis (Arabidopsis thaliana) cals5 mutant, in which callose synthesis is inhibited. However, this restoration of fertility was impaired by the transient silencing of PbrCalS1B.1, which restricts callose plug formation and shortens the pear pollen tube lifecycle. More specifically, PbrbZIP52 regulated PbrCalS1B.1 transcription by binding to promoter A-box elements to maintain the periodic formation of callose plugs and normal pollen tube growth, ultimately leading to double fertilization. This study confirmed that PbrbZIP52 positively affects pear pollen tube longevity by promoting callose synthesis. This finding may be useful for breeding high-yielding pear cultivars and stabilizing fruit setting in commercial orchards.
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Affiliation(s)
- Zhongheng Xia
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Binxu Wen
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jing Shao
- Institute of Pomology, Jilin Academy of Agricultural Sciences, Gongzhuling 136100, China
| | - Tianci Zhang
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mengmeng Hu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lin Lin
- Anxi College of Tea Science, Fujian Agriculture and Forestry University, Anxi 362406, China
| | - Yiping Zheng
- Fujian Academy of Agricultural Sciences Biotechnology Institute, Fuzhou 350003, China
| | - Zhixin Shi
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xinlin Dong
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Juanjuan Song
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yuanshan Li
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yongjie Wu
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yafang Yuan
- Department of Horticulture and Landscape Architecture, Fujian Vocational College of Agriculture, Fuzhou 350119, China
| | - Juyou Wu
- Center of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Qingxi Chen
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jianqing Chen
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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6
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Noble JA, Bielski NV, Liu MCJ, DeFalco TA, Stegmann M, Nelson ADL, McNamara K, Sullivan B, Dinh KK, Khuu N, Hancock S, Shiu SH, Zipfel C, Cheung AY, Beilstein MA, Palanivelu R. Evolutionary analysis of the LORELEI gene family in plants reveals regulatory subfunctionalization. PLANT PHYSIOLOGY 2022; 190:2539-2556. [PMID: 36156105 PMCID: PMC9706458 DOI: 10.1093/plphys/kiac444] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/31/2022] [Indexed: 06/16/2023]
Abstract
A signaling complex comprising members of the LORELEI (LRE)-LIKE GPI-anchored protein (LLG) and Catharanthus roseus RECEPTOR-LIKE KINASE 1-LIKE (CrRLK1L) families perceive RAPID ALKALINIZATION FACTOR (RALF) peptides and regulate growth, reproduction, immunity, and stress responses in Arabidopsis (Arabidopsis thaliana). Genes encoding these proteins are members of multigene families in most angiosperms and could generate thousands of signaling complex variants. However, the links between expansion of these gene families and the functional diversification of this critical signaling complex as well as the evolutionary factors underlying the maintenance of gene duplicates remain unknown. Here, we investigated LLG gene family evolution by sampling land plant genomes and explored the function and expression of angiosperm LLGs. We found that LLG diversity within major land plant lineages is primarily due to lineage-specific duplication events, and that these duplications occurred both early in the history of these lineages and more recently. Our complementation and expression analyses showed that expression divergence (i.e. regulatory subfunctionalization), rather than functional divergence, explains the retention of LLG paralogs. Interestingly, all but one monocot and all eudicot species examined had an LLG copy with preferential expression in male reproductive tissues, while the other duplicate copies showed highest levels of expression in female or vegetative tissues. The single LLG copy in Amborella trichopoda is expressed vastly higher in male compared to in female reproductive or vegetative tissues. We propose that expression divergence plays an important role in retention of LLG duplicates in angiosperms.
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Affiliation(s)
- Jennifer A Noble
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA
| | - Nicholas V Bielski
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona 85721, USA
| | - Ming-Che James Liu
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Thomas A DeFalco
- Institute of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Martin Stegmann
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, UK
- Phytopathology, TUM School of Life Sciences, Technical University of Munich, Freising, Germany
| | - Andrew D L Nelson
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853, USA
| | - Kara McNamara
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Brooke Sullivan
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Khanhlinh K Dinh
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Nicholas Khuu
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Sarah Hancock
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA
| | - Shin-Han Shiu
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Computational Mathematics, Science, and Engineering, Michigan State University, East Lansing, Michigan 48824, USA
| | - Cyril Zipfel
- Institute of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
- The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Alice Y Cheung
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003, USA
- Molecular and Cell Biology Program, University of Massachusetts, Amherst, Massachusetts 01003, USA
- Plant Biology Graduate Program, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Mark A Beilstein
- School of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA
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7
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Fan D, Yuan X, Wu W, Zhu R, Yang X, Liao Y, Ma Y, Xiao C, Chen C, Liu C, Wang H, Qin P. Self-shrinking soft demoulding for complex high-aspect-ratio microchannels. Nat Commun 2022; 13:5083. [PMID: 36038593 PMCID: PMC9424246 DOI: 10.1038/s41467-022-32859-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 08/22/2022] [Indexed: 11/23/2022] Open
Abstract
Microchannels are the essential elements in animals, plants, and various artificial devices such as soft robotics, wearable sensors, and organs-on-a-chip. However, three-dimensional (3D) microchannels with complex geometry and a high aspect ratio remain challenging to generate by conventional methods such as soft lithography, template dissolution, and matrix swollen processes, although they are widespread in nature. Here, we propose a simple and solvent-free fabrication method capable of producing monolithic microchannels with complex 3D structures, long length, and small diameter. A soft template and a peeling-dominant template removal process are introduced to the demoulding process, which is referred to as soft demoulding here. In combination with thermal drawing technology, microchannels with a small diameter (10 µm), a high aspect ratio (6000, length-to-diameter), and intricate 3D geometries are generated. We demonstrate the vast applicability and significant impact of this technology in multiple scenarios, including soft robotics, wearable sensors, soft antennas, and artificial vessels. Microchannels are the essential elements for the design of artificial devices but the fabrication of three dimensional (3D) microchannels with complex geometry and a high aspect ratio remains challenging. Here, the authors demonstrate a simple and solvent-free fabrication method capable of producing monolithic microchannels with complex 3D structures, long length, and small diameter.
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Affiliation(s)
- Dongliang Fan
- Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xi Yuan
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, Guangdong, 518055, China.,Center of Precision Medicine and Healthcare, Tsinghua-Berkeley Shenzhen Institute, Shenzhen, Guangdong Province, 518055, China
| | - Wenyu Wu
- School of System Design and Intelligent Manufacturing, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Renjie Zhu
- Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xin Yang
- Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Yuxuan Liao
- Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Yunteng Ma
- Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Chufan Xiao
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, Guangdong, 518055, China.,Center of Precision Medicine and Healthcare, Tsinghua-Berkeley Shenzhen Institute, Shenzhen, Guangdong Province, 518055, China
| | - Cheng Chen
- Department of Biomedical Engineering, National University of Singapore, Singapore, 117575, Singapore
| | - Changyue Liu
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, Guangdong, 518055, China.,Center of Precision Medicine and Healthcare, Tsinghua-Berkeley Shenzhen Institute, Shenzhen, Guangdong Province, 518055, China
| | - Hongqiang Wang
- Shenzhen Key Laboratory of Biomimetic Robotics and Intelligent Systems, Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China. .,Guangdong Provincial Key Laboratory of Human-Augmentation and Rehabilitation Robotics in Universities, Southern University of Science and Technology, Shenzhen, 518055, China. .,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 510000, China.
| | - Peiwu Qin
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, Guangdong, 518055, China. .,Center of Precision Medicine and Healthcare, Tsinghua-Berkeley Shenzhen Institute, Shenzhen, Guangdong Province, 518055, China.
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8
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Deng M, Yao K, Shi C, Shao W, Li Q. Development of Quercus acutissima (Fagaceae) pollen tubes inside pistils during the sexual reproduction process. PLANTA 2022; 256:16. [PMID: 35737139 DOI: 10.1007/s00425-022-03937-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Extensive histology of pistillate flowers revealed two pollen tube arresting sites (the style-joining and micropyle) within the pistil of Quercus acutissima during the postpollination-prezygotic stage, which reflects a unique female and male gametophyte recognition/selection mechanism. Sexual reproduction is among the most delicate and essential stages in plant life cycles and involves a series of precise interactions between pistils and male gametophytes. Quercus is a woody genus that dominates Northern Hemisphere forests and is notorious for interspecific hybridization, but its sexual reproduction is poorly understood, especially its pollen tube (PT) growth dynamics within pistils. This study used microtome techniques and scanning electron microscopy to observe the postpollination-prezygotic process in the biennially fruiting oak Quercus acutissima. Many pollen grains germinated at anthesis instantly, and PTs penetrated stigmatic surfaces and elongated through the stylar transmitting tissue, then arrested at style-joining for about 12-13 months. Few PTs resumed growth along the compitum in the upper ovarian locule wall in the subsequent April, concurrent with the rapid growth of rudimentary ovules. PTs arrived in the micropyle, and upper septum during megaspore mother cell meiosis, then arrested again for 7-10 days waiting for the embryo sac maturation. Fertilization occurred one week later. Our study shows a clear female dominant crosstalk growth pattern between PT and the ovule. The intermittent PT growth might reflect a unique male gametophyte recognition/selection mechanism to avoid self-pollination and enhance PT competition while increasing interspecific hybridization.
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Affiliation(s)
- Min Deng
- School of Ecology and Environmental Science, Yunnan University, Kunming, 650500, Yunnan, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Institute of Biodiversity, Yunnan University, Kunming, 650504, Yunnan, China
- Yunnan Key Laboratory for Integrative Conservation of Plant Species With Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Kaiping Yao
- School of Ecology and Environmental Science, Yunnan University, Kunming, 650500, Yunnan, China
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Institute of Biodiversity, Yunnan University, Kunming, 650504, Yunnan, China
- Yunnan Key Laboratory for Integrative Conservation of Plant Species With Extremely Small Populations, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Chengcheng Shi
- Shanghai Chenshan Botanical Garden, Shanghai, 201602, China
| | - Wen Shao
- Shanghai Chenshan Botanical Garden, Shanghai, 201602, China
| | - Qiansheng Li
- Horticultural Sciences Department, University of Florida, FL, 32611, USA.
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9
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Hao G, Zhao X, Zhang M, Ying J, Yu F, Li S, Zhang Y. Vesicle trafficking in
Arabidopsis
pollen tubes. FEBS Lett 2022; 596:2231-2242. [DOI: 10.1002/1873-3468.14343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/08/2022] [Accepted: 03/08/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Guang‐Jiu Hao
- State Key Laboratory of Crop Biology College of Life Sciences Shandong Agricultural University Tai’an, Shandong China
| | - Xin‐Ying Zhao
- State Key Laboratory of Crop Biology College of Life Sciences Shandong Agricultural University Tai’an, Shandong China
| | | | - Jun Ying
- State Key Laboratory of Crop Biology College of Life Sciences Shandong Agricultural University Tai’an, Shandong China
| | - Fei Yu
- State Key Laboratory of Crop Biology College of Life Sciences Shandong Agricultural University Tai’an, Shandong China
| | - Sha Li
- State Key Laboratory of Crop Biology College of Life Sciences Shandong Agricultural University Tai’an, Shandong China
| | - Yan Zhang
- State Key Laboratory of Crop Biology College of Life Sciences Shandong Agricultural University Tai’an, Shandong China
- College of Life Sciences Nankai University China
- Frontiers Science Center for Cell Responses Nankai University China
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10
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Hiwatashi Y, Shimada M, Mikami K, Takada N. Establishment of a Live-Imaging Analysis for Polarized Growth of Conchocelis in the Multicellular Red Alga Neopyropia yezoensis. FRONTIERS IN PLANT SCIENCE 2022; 12:716011. [PMID: 35251057 PMCID: PMC8888420 DOI: 10.3389/fpls.2021.716011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
A wide range of tip-growing cells in plants display polarized cell growth, which is an essential cellular process for the form and function of individual cells. Understanding of the regulatory mechanisms underlying tip growth in terrestrial plants has improved. Cellular processes involved in tip growth have also been investigated in some algae species that form filamentous cells, but their regulatory mechanisms remain unclear. In the macro red alga Neopyropia yezoensis, for which genome information has recently been released, the conchocelis apical cell exhibits tip growth and forms a filamentous structure. Here, we report a live-imaging technique using high-resolution microscopy to analyze the tip growth and cell division of N. yezoensis conchocelis. This imaging analysis addressed tip growth dynamics and cell division in conchocelis apical cells. The directionality and tip growth expansion were disrupted by the application of cytoskeletal drugs, suggesting the involvement of microtubules (MTs) and actin filaments (AFs) in these processes. A growing apical cell mostly contained a single chloroplast that moved toward the expanding part of the apical cell. Drug application also inhibited chloroplast movement, implying that the movement may be dependent on the cytoskeleton. The study determined that live-imaging analysis is a versatile approach for exploring the dynamics of tip growth and cell division in N. yezoensis conchocelis, which provides insights into the regulatory mechanisms underlying cellular growth in multicellular red algae.
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Affiliation(s)
- Yuji Hiwatashi
- Graduate School of Food, Agricultural and Environmental Sciences, Miyagi University, Sendai, Japan
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
| | - Mizuho Shimada
- Graduate School of Food, Agricultural and Environmental Sciences, Miyagi University, Sendai, Japan
| | - Koji Mikami
- Graduate School of Food, Agricultural and Environmental Sciences, Miyagi University, Sendai, Japan
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
| | - Nagisa Takada
- School of Food Industrial Sciences, Miyagi University, Sendai, Japan
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11
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Satake A, Kelly D. Delayed fertilization facilitates flowering time diversity in Fagaceae. Philos Trans R Soc Lond B Biol Sci 2021; 376:20210115. [PMID: 34657457 PMCID: PMC8520785 DOI: 10.1098/rstb.2021.0115] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2021] [Indexed: 11/12/2022] Open
Abstract
Fagaceae includes typical masting species that exhibit highly synchronized and fluctuating acorn production. Fagaceae shows an interesting feature in that fertilization is delayed by several weeks to more than 1 year after pollination. Although delayed fertilization was recorded over a century ago, the evolutionary advantage of delayed fertilization is still poorly understood. Here, we present a new hypothesis that delayed fertilization facilitates temporal niche differentiation via non-overlapping flowering times among species. Comparing flowering and fruiting times in 228 species from five genera in Fagaceae, we first show that there is a close association between a wider spread of flowering times and the likelihood of a 2-year fruiting habit in which there is a long delay from pollination to fertilization. To study the coevolution of flowering time and delayed fertilization, we developed a mathematical model that incorporates the effects of competition for pollinators, seed predator satiation and unfavourable season for reproduction on fitness. The model shows that delayed fertilization facilitates the diversification of flowering time in a population, which is advantageous for animal-pollinated trees that compete over pollinators. Our new hypothesis about the coevolution of delayed fertilization and flowering time will provide new insight into the evolution of masting. This article is part of the theme issue 'The ecology and evolution of synchronized seed production in plants'.
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Affiliation(s)
- Akiko Satake
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka 819-0395, Japan
| | - Dave Kelly
- Department of Biological Sciences, University of Canterbury, Christchurch 8140, New Zealand
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12
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Westermann J. Two Is Company, but Four Is a Party-Challenges of Tetraploidization for Cell Wall Dynamics and Efficient Tip-Growth in Pollen. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10112382. [PMID: 34834745 PMCID: PMC8623246 DOI: 10.3390/plants10112382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/01/2021] [Accepted: 11/03/2021] [Indexed: 05/27/2023]
Abstract
Some cells grow by an intricately coordinated process called tip-growth, which allows the formation of long tubular structures by a remarkable increase in cell surface-to-volume ratio and cell expansion across vast distances. On a broad evolutionary scale, tip-growth has been extraordinarily successful, as indicated by its recurrent 're-discovery' throughout evolutionary time in all major land plant taxa which allowed for the functional diversification of tip-growing cell types across gametophytic and sporophytic life-phases. All major land plant lineages have experienced (recurrent) polyploidization events and subsequent re-diploidization that may have positively contributed to plant adaptive evolutionary processes. How individual cells respond to genome-doubling on a shorter evolutionary scale has not been addressed as elaborately. Nevertheless, it is clear that when polyploids first form, they face numerous important challenges that must be overcome for lineages to persist. Evidence in the literature suggests that tip-growth is one of those processes. Here, I discuss the literature to present hypotheses about how polyploidization events may challenge efficient tip-growth and strategies which may overcome them: I first review the complex and multi-layered processes by which tip-growing cells maintain their cell wall integrity and steady growth. I will then discuss how they may be affected by the cellular changes that accompany genome-doubling. Finally, I will depict possible mechanisms polyploid plants may evolve to compensate for the effects caused by genome-doubling to regain diploid-like growth, particularly focusing on cell wall dynamics and the subcellular machinery they are controlled by.
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Affiliation(s)
- Jens Westermann
- Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Universitätsstrasse 2, 8092 Zürich, Switzerland
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13
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Laggoun F, Ali N, Tourneur S, Prudent G, Gügi B, Kiefer-Meyer MC, Mareck A, Cruz F, Yvin JC, Nguema-Ona E, Mollet JC, Jamois F, Lehner A. Two Carbohydrate-Based Natural Extracts Stimulate in vitro Pollen Germination and Pollen Tube Growth of Tomato Under Cold Temperatures. FRONTIERS IN PLANT SCIENCE 2021; 12:552515. [PMID: 34691089 PMCID: PMC8529017 DOI: 10.3389/fpls.2021.552515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
To date, it is widely accepted by the scientific community that many agricultural regions will experience more extreme temperature fluctuations. These stresses will undoubtedly impact crop production, particularly fruit and seed yields. In fact, pollination is considered as one of the most temperature-sensitive phases of plant development and until now, except for the time-consuming and costly processes of genetic breeding, there is no immediate alternative to address this issue. In this work, we used a multidisciplinary approach using physiological, biochemical, and molecular techniques for studying the effects of two carbohydrate-based natural activators on in vitro tomato pollen germination and pollen tube growth cultured in vitro under cold conditions. Under mild and strong cold temperatures, these two carbohydrate-based compounds significantly enhanced pollen germination and pollen tube growth. The two biostimulants did not induce significant changes in the classical molecular markers implicated in pollen tube growth. Neither the number of callose plugs nor the CALLOSE SYNTHASE genes expression were significantly different between the control and the biostimulated pollen tubes when pollens were cultivated under cold conditions. PECTIN METHYLESTERASE (PME) activities were also similar but a basic PME isoform was not produced or inactive in pollen grown at 8°C. Nevertheless, NADPH oxidase (RBOH) gene expression was correlated with a higher number of viable pollen tubes in biostimulated pollen tubes compared to the control. Our results showed that the two carbohydrate-based products were able to reduce in vitro the effect of cold temperatures on tomato pollen tube growth and at least for one of them to modulate reactive oxygen species production.
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Affiliation(s)
- Ferdousse Laggoun
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
- Sanofi Pasteur, Val-de-Reuil, France
| | - Nusrat Ali
- Centre Mondial de l’Innovation, Laboratoire Nutrition Végétale, Groupe Roullier, Saint-Malo, France
| | - Sabine Tourneur
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
- Laboratoire de Biologie et Pathologie Végétales, Université de Nantes, Université Bretagne Loire, Nantes, France
| | - Grégoire Prudent
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
| | - Bruno Gügi
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
| | - Marie-Christine Kiefer-Meyer
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
| | - Alain Mareck
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
| | - Florence Cruz
- Centre Mondial de l’Innovation, Laboratoire Nutrition Végétale, Groupe Roullier, Saint-Malo, France
| | - Jean-Claude Yvin
- Centre Mondial de l’Innovation, Laboratoire Nutrition Végétale, Groupe Roullier, Saint-Malo, France
| | - Eric Nguema-Ona
- Centre Mondial de l’Innovation, Laboratoire Nutrition Végétale, Groupe Roullier, Saint-Malo, France
| | - Jean-Claude Mollet
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
| | - Frank Jamois
- Centre Mondial de l’Innovation, Laboratoire Nutrition Végétale, Groupe Roullier, Saint-Malo, France
| | - Arnaud Lehner
- UNIROUEN, Normandie Université, Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale, SFR NORVEGE FED 4277, Carnot I2C, IRIB, Rouen, France
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14
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Rashid K, Rashid S, Ganie AH, Nawchoo IA, Khuroo AA. Meiotic Studies, Pollen Fertility and Seed Set of Trillium govanianum, an Endangered Endemic Plant Species of the Himalaya. CYTOLOGIA 2021. [DOI: 10.1508/cytologia.86.245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Kausar Rashid
- Plant Reproductive Biology, Genetic Diversity and Phytochemistry Research Laboratory, Department of Botany, University of Kashmir
| | - Sufiya Rashid
- Plant Reproductive Biology, Genetic Diversity and Phytochemistry Research Laboratory, Department of Botany, University of Kashmir
| | | | - Irshad A. Nawchoo
- Plant Reproductive Biology, Genetic Diversity and Phytochemistry Research Laboratory, Department of Botany, University of Kashmir
| | - Anzar A. Khuroo
- Centre for Biodiversity & Taxonomy, Department of Botany, University of Kashmir
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15
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Leslie AB, Simpson C, Mander L. Reproductive innovations and pulsed rise in plant complexity. Science 2021; 373:1368-1372. [PMID: 34529461 DOI: 10.1126/science.abi6984] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Andrew B Leslie
- Geological Sciences Department, Stanford University, 450 Jane Stanford Way, Building 320, Room 118, Stanford, CA 94305, USA
| | - Carl Simpson
- Geological Sciences, University of Colorado Museum of Natural History, University of Colorado Boulder, Campus Box 265, Boulder, CO 80304, USA
| | - Luke Mander
- School of Environment, Earth and Ecosystem Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
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16
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Ke CJ, Lin XJ, Zhang BY, Chen LY. Turgor regulation defect 1 proteins play a conserved role in pollen tube reproductive innovation of the angiosperms. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1356-1365. [PMID: 33735469 DOI: 10.1111/tpj.15241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/11/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Sexual reproduction in angiosperms is siphonogamous, and the interaction between pollen tube and pistil is critical for successful fertilization. Our previous study demonstrated that mutation of the Arabidopsis turgor regulation defect 1 (TOD1) gene leads to reduced male fertility, a result of retarded pollen tube growth in the pistil. TOD1 encodes a Golgi-localized alkaline ceramidase, a key enzyme for the production of sphingosine-1-phosphate (S1P), which is involved in the regulation of turgor pressure in plant cells. However, whether TOD1s play a conserved role in the innovation of siphonogamy is largely unknown. In this study, we provide evidence that OsTOD1, which is similar to AtTOD1, is also preferentially expressed in rice pollen grains and pollen tubes. OsTOD1 knockout results in reduced pollen tube growth potential in rice pistil. Both the OsTOD1 genomic sequence with its own promoter and the coding sequence under the AtTOD1 promoter can partially rescue the attod1 mutant phenotype. Furthermore, TOD1s from other angiosperm species can partially rescue the attod1 mutant phenotype, while TOD1s from gymnosperm species are not able to complement the attod1 mutant phenotype. Our data suggest that TOD1 acts conservatively in angiosperms, and this opens up an opportunity to dissect the role of sphingolipids in pollen tube growth in angiosperms.
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Affiliation(s)
- Chang-Jiao Ke
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xian-Ju Lin
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Bao-Yu Zhang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Li-Yu Chen
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Center for Genomics and Biotechnology, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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17
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Calabrese EJ, Agathokleous E. Pollen biology and hormesis: Pollen germination and pollen tube elongation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 762:143072. [PMID: 33139003 DOI: 10.1016/j.scitotenv.2020.143072] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 06/11/2023]
Abstract
This paper evaluated the occurrence of hormetic dose responses in pollen reported over the past eight decades. Hormetic doses responses were induced by a wide range of chemical and physical agents in 34 plant species for pollen germination and pollen tube growth/elongation. Agents inducing such hormetic dose/concentration responses in pollen included nutrients, growth-promoting agents, plant and animal hormones, toxic substances, including heavy metals such as cadmium, gaseous pollutants such as ozone, as well as ionizing and non-ionizing radiation. This paper provides further evidence for the broad generality of the hormesis dose response, supporting substantial prior findings that the hormetic response is independent of biological model, inducing agent, and endpoints measured. Given the widespread potential of inducing hormetic dose responses in pollen, these findings indicate the need to explore their emerging biological, ecological, agricultural, economic and public health implications.
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Affiliation(s)
- Edward J Calabrese
- Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01007, United States of America.
| | - Evgenios Agathokleous
- Key Laboratory of Agrometeorology of Jiangsu Province, Institute of Ecology, School of Applied Meteorology, Nanjing University of Information Science & Technology, Nanjing 210044, China.
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18
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Flores-Tornero M, Vogler F, Mutwil M, Potěšil D, Ihnatová I, Zdráhal Z, Sprunck S, Dresselhaus T. Transcriptomic and Proteomic Insights into Amborella trichopoda Male Gametophyte Functions. PLANT PHYSIOLOGY 2020; 184:1640-1657. [PMID: 32989009 PMCID: PMC7723084 DOI: 10.1104/pp.20.00837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/16/2020] [Indexed: 05/27/2023]
Abstract
Flowering plants (angiosperms) are characterized by pollen tubes (PTs; male gametophytes) carrying two immobile sperm cells that grow over long distances through the carpel toward the ovules, where double fertilization is executed. It is not understood how these reproductive structures evolved, which genes occur de novo in male gametophytes of angiosperms, and to which extent PT functions are conserved among angiosperms. To contribute to a deeper understanding of the evolution of gametophyte functions, we generated RNA sequencing data from seven reproductive and two vegetative control tissues of the basal angiosperm Amborella trichopoda and complemented these with proteomic data of pollen grains (PGs) and PTs. The eudicot model plant Arabidopsis (Arabidopsis thaliana) served as a reference organism for data analysis, as more than 200 genes have been associated with male gametophyte functions in this species. We describe methods to collect bicellular A. trichopoda PGs, to induce their germination in vitro, and to monitor PT growth and germ cell division. Transcriptomic and proteomic analyses indicate that A. trichopoda PGs are prepared for germination requiring lipids, energy, but likely also reactive oxygen species, while PTs are especially characterized by catabolic/biosynthetic and transport processes including cell wall biosynthesis and gene regulation. Notably, a number of pollen-specific genes were lacking in Arabidopsis, and the number of genes involved in pollen signaling is significantly reduced in A. trichopoda In conclusion, we provide insight into male gametophyte functions of the most basal angiosperm and establish a valuable resource for future studies on the evolution of flowering plants.
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Affiliation(s)
- María Flores-Tornero
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Frank Vogler
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Marek Mutwil
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - David Potěšil
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic
| | - Ivana Ihnatová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic
- RECETOX, Faculty of Science, Masaryk University, CZ-62500 Brno, Czech Republic
| | - Zbyněk Zdráhal
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, CZ-62500 Brno, Czech Republic
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, 93053 Regensburg, Germany
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19
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Lu Y, Moran Lauter AN, Makkena S, Scott MP, Evans MMS. Insights into the molecular control of cross-incompatibility in Zea mays. PLANT REPRODUCTION 2020; 33:117-128. [PMID: 32865620 DOI: 10.1007/s00497-020-00394-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 08/18/2020] [Indexed: 06/11/2023]
Abstract
Gametophytic cross-incompatibility systems in corn have been the subject of genetic studies for more than a century. They have tremendous economic potential as a genetic mechanism for controlling fertilization without controlling pollination. Three major genetically distinct and functionally equivalent cross-incompatibility systems exist in Zea mays: Ga1, Tcb1, and Ga2. All three confer reproductive isolation between maize or teosinte varieties with different haplotypes at any one locus. These loci confer genetically separable functions to the silk and pollen: a female function that allows the silk to block fertilization by non-self-type pollen and a male function that overcomes the block of the female function from the same locus. Identification of some of these genes has shed light on the reproductive isolation they confer. The identification of both male and female factors as pectin methylesterases reveals the importance of pectin methylesterase activity in controlling the decision between pollen acceptance versus rejection, possibly by regulating the degree of methylesterification of the pollen tube cell wall. The appropriate level and spatial distribution of pectin methylesterification is critical for pollen tube growth and is affected by both pectin methylesterases and pectin methylesterase inhibitors. We present a molecular model that explains how cross-incompatibility systems may function that can be tested in Zea and uncharacterized cross-incompatibility systems. Molecular characterization of these loci in conjunction with further refinement of the underlying molecular and cellular mechanisms will allow researchers to bring new and powerful tools to bear on understanding reproductive isolation in Zea mays and related species.
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Affiliation(s)
- Yongxian Lu
- Department of Plant Biology, Carnegie Institute for Science, Stanford, CA, 94305, USA
| | | | | | - M Paul Scott
- Corn Insects and Crop Genetics Research Unit, USDA ARS, Ames, IA, 50011, USA
| | - Matthew M S Evans
- Department of Plant Biology, Carnegie Institute for Science, Stanford, CA, 94305, USA.
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20
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Adhikari PB, Liu X, Kasahara RD. Mechanics of Pollen Tube Elongation: A Perspective. FRONTIERS IN PLANT SCIENCE 2020; 11:589712. [PMID: 33193543 PMCID: PMC7606272 DOI: 10.3389/fpls.2020.589712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/30/2020] [Indexed: 05/13/2023]
Abstract
Pollen tube (PT) serves as a vehicle that delivers male gametes (sperm cells) to a female gametophyte during double fertilization, which eventually leads to the seed formation. It is one of the fastest elongating structures in plants. Normally, PTs traverse through the extracellular matrix at the transmitting tract after penetrating the stigma. While the endeavor may appear simple, the molecular processes and mechanics of the PT elongation is yet to be fully resolved. Although it is the most studied "tip-growing" structure in plants, several features of the structure (e.g., Membrane dynamics, growth behavior, mechanosensing etc.) are only partially understood. In many aspects, PTs are still considered as a tissue rather than a "unique cell." In this review, we have attempted to discuss mainly on the mechanics behind PT-elongation and briefly on the molecular players involved in the process. Four aspects of PTs are particularly discussed: the PT as a cell, its membrane dynamics, mechanics of its elongation, and the potential mechanosensors involved in its elongation based on relevant findings in both plant and non-plant models.
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Affiliation(s)
- Prakash Babu Adhikari
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaoyan Liu
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ryushiro D. Kasahara
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, China
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21
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Lindberg CL, Hanslin HM, Schubert M, Marcussen T, Trevaskis B, Preston JC, Fjellheim S. Increased above-ground resource allocation is a likely precursor for independent evolutionary origins of annuality in the Pooideae grass subfamily. THE NEW PHYTOLOGIST 2020; 228:318-329. [PMID: 32421861 DOI: 10.1111/nph.16666] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Semelparous annual plants flower a single time during their 1-yr life cycle, investing much of their energy into rapid reproduction. By contrast, iteroparous perennial plants flower multiple times over several years, and partition their resources between reproduction and persistence. To which extent evolutionary transitions between life-cycle strategies are internally constrained at the developmental, genetic and phylogenetic level is unknown. Here we study the evolution of life-cycle strategies in the grass subfamily Pooideae and test if transitions between them are facilitated by evolutionary precursors. We integrate ecological, life-cycle strategy and growth data in a phylogenetic framework. We investigate if growth traits are candidates for a precursor. Species in certain Pooideae clades are predisposed to evolve annuality from perenniality, potentially due to the shared inheritance of specific evolutionary precursors. Seasonal dry climates, which have been linked to annuality, were only able to select for transitions to annuality when the precursor was present. Allocation of more resources to above-ground rather than below-ground growth is a candidate for the precursor. Our findings support the hypothesis that only certain lineages can respond quickly to changing external conditions by switching their life-cycle strategy, likely due to the presence of evolutionary precursors.
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Affiliation(s)
- Camilla Lorange Lindberg
- Department of Plant Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Hans Martin Hanslin
- Department of Urban Greening and Vegetation Ecology, Norwegian Institute of Bioeconomy Research, Ås, 1431, Norway
| | - Marian Schubert
- Department of Plant Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Thomas Marcussen
- Department of Plant Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, 1432, Norway
| | - Ben Trevaskis
- Commonwealth Scientific and Industrial Research Organization, Canberra, ACT, 2601, Australia
| | | | - Siri Fjellheim
- Department of Plant Sciences, Faculty of Biosciences, Norwegian University of Life Sciences, Ås, 1432, Norway
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22
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Scholz P, Anstatt J, Krawczyk HE, Ischebeck T. Signalling Pinpointed to the Tip: The Complex Regulatory Network That Allows Pollen Tube Growth. PLANTS (BASEL, SWITZERLAND) 2020; 9:E1098. [PMID: 32859043 PMCID: PMC7569787 DOI: 10.3390/plants9091098] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/18/2020] [Accepted: 08/23/2020] [Indexed: 12/13/2022]
Abstract
Plants display a complex life cycle, alternating between haploid and diploid generations. During fertilisation, the haploid sperm cells are delivered to the female gametophyte by pollen tubes, specialised structures elongating by tip growth, which is based on an equilibrium between cell wall-reinforcing processes and turgor-driven expansion. One important factor of this equilibrium is the rate of pectin secretion mediated and regulated by factors including the exocyst complex and small G proteins. Critically important are also non-proteinaceous molecules comprising protons, calcium ions, reactive oxygen species (ROS), and signalling lipids. Among the latter, phosphatidylinositol 4,5-bisphosphate and the kinases involved in its formation have been assigned important functions. The negatively charged headgroup of this lipid serves as an interaction point at the apical plasma membrane for partners such as the exocyst complex, thereby polarising the cell and its secretion processes. Another important signalling lipid is phosphatidic acid (PA), that can either be formed by the combination of phospholipases C and diacylglycerol kinases or by phospholipases D. It further fine-tunes pollen tube growth, for example by regulating ROS formation. How the individual signalling cues are intertwined or how external guidance cues are integrated to facilitate directional growth remain open questions.
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Affiliation(s)
- Patricia Scholz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
| | | | | | - Till Ischebeck
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences and Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig Weg 11, D-37077 Goettingen, Germany; (J.A.); (H.E.K.)
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Vogler H, Burri JT, Nelson BJ, Grossniklaus U. Simultaneous measurement of turgor pressure and cell wall elasticity in growing pollen tubes. Methods Cell Biol 2020; 160:297-310. [PMID: 32896323 DOI: 10.1016/bs.mcb.2020.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Plant growth and morphogenesis are tightly controlled processes of division and expansion of individual cells. To fully describe the factors that influence cell expansion, it is necessary to quantify the counteracting forces of turgor pressure and cell wall stiffness, which together determine whether and how a cell expands. Several methods have been developed to measure these parameters, but most of them provide only values for one or the other, and thus require complex models to derive the missing quantity. Furthermore, available methods for turgor measurement are either accurate but invasive, like the pressure probe; or they lack accuracy, such as incipient plasmolysis or indentation-based methods that rely on information about the mechanical properties of the cell wall. Here, we describe a system that overcomes many of the above-mentioned disadvantages using growing pollen tubes of Lilium longiflorum as a model. By combining non-invasive microindentation and cell compression experiments, we separately measure turgor pressure and cell wall elasticity on the same pollen tube in parallel. Due to the modularity of the setup and the large range of the micro-positioning system, our method is not limited to pollen tubes but could be used to investigate the biomechanical properties of many other cell types or tissues.
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Affiliation(s)
- Hannes Vogler
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland.
| | - Jan T Burri
- Multi-Scale Robotics Lab, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Bradley J Nelson
- Multi-Scale Robotics Lab, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
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Williams JH, Oliveira PE. For things to stay the same, things must change: polyploidy and pollen tube growth rates. ANNALS OF BOTANY 2020; 125:925-935. [PMID: 31957784 PMCID: PMC7218811 DOI: 10.1093/aob/mcaa007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 01/17/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Pollen tube growth rate (PTGR) is an important single-cell performance trait that may evolve rapidly under haploid selection. Angiosperms have experienced repeated cycles of polyploidy (whole genome duplication), and polyploidy has cell-level phenotypic consequences arising from increased bulk DNA amount and numbers of genes and their interactions. We sought to understand potential effects of polyploidy on several underlying determinants of PTGR - pollen tube dimensions and construction rates - by comparing diploid-polyploid near-relatives in Betula (Betulaceae) and Handroanthus (Bignoniaceae). METHODS We performed intraspecific, outcrossed hand-pollinations on pairs of flowers. In one flower, PTGR was calculated from the longest pollen tube per time of tube elongation. In the other, styles were embedded in glycol methacrylate, serial-sectioned in transverse orientation, stained and viewed at 1000× to measure tube wall thicknesses (W) and circumferences (C). Volumetric growth rate (VGR) and wall production rate (WPR) were then calculated for each tube by multiplying cross-sectional tube area (πr2) or wall area (W × C), by the mean PTGR of each maternal replicate respectively. KEY RESULTS In Betula and Handroanthus, the hexaploid species had significantly wider pollen tubes (13 and 25 %, respectively) and significantly higher WPRs (22 and 18 %, respectively) than their diploid congeners. PTGRs were not significantly different in both pairs, even though wider polyploid tubes were predicted to decrease PTGRs by 16 and 20 %, respectively. CONCLUSIONS The larger tube sizes of polyploids imposed a substantial materials cost on PTGR, but polyploids also exhibited higher VGRs and WPRs, probably reflecting the evolution of increased metabolic activity. Recurrent cycles of polyploidy followed by genome reorganization may have been important for the evolution of fast PTGRs in angiosperms, involving a complex interplay between correlated changes in ploidy level, genome size, cell size and pollen tube energetics.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, USA
| | - Paulo E Oliveira
- Instituto de Biologia, Universidade Federal de Uberlândia, Campus Umuarama, Uberlândia, Minas Gerais 38405-320 Brazil
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Taylor ML, Giffei BL, Dang CL, Wilden AE, Altrichter KM, Baker EC, Nguyen R, Oki DS. Reproductive ecology and postpollination development in the hydrophilous monocot Ruppia maritima. AMERICAN JOURNAL OF BOTANY 2020; 107:689-699. [PMID: 32170723 DOI: 10.1002/ajb2.1447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 01/21/2020] [Indexed: 06/10/2023]
Abstract
PREMISE Water-pollination (hydrophily) is a rare but important pollination mechanism that has allowed angiosperms to colonize marine and aquatic habitats. Hydrophilous plants face unique reproductive challenges, and many have evolved characteristic pollen traits and pollination strategies that may have downstream consequences for pollen performance. However, little is known about reproductive development in the life history stage between pollination and fertilization (the progamic phase) in hydrophilous plants. The purpose of this study was to characterize reproductive ecology and postpollination development in water-pollinated Ruppia maritima L. METHODS Naturally pollinated inflorescences of R. maritima were collected from the field. Experimental pollinations using both putatively outcross and self pollen were conducted in the greenhouse and inflorescences were collected at appropriate intervals after pollination. Pollen reception, pollen germination, pollen tube growth, and carpel morphology were characterized. RESULTS Ruppia maritima exhibits incomplete protogyny, allowing for delayed selfing. Pollen germinated within 15 min after pollination. The average shortest possible pollen tube pathway was 425 μm and pollen tubes first reached the ovule at 45 min after pollination. The mean adjusted pollen tube growth rate was 551 μm/h. CONCLUSIONS Ruppia pollen is adapted for rapid pollen germination, which is likely advantageous in an aquatic habitat. Small effective pollen loads suggest that pollen competition intensity is low. Selection for traits such as a long period of stigma receptivity, fast pollen germination, and carpel morphology likely played a larger role in shaping postpollination reproductive development in Ruppia than evolution in pollen tube growth rates.
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Affiliation(s)
- Mackenzie L Taylor
- Department of Biology, Creighton University, Omaha, Nebraska, 68178, USA
| | - Bridget L Giffei
- Department of Biology, Creighton University, Omaha, Nebraska, 68178, USA
| | - Christie L Dang
- Department of Biology, Creighton University, Omaha, Nebraska, 68178, USA
| | - Ana E Wilden
- Department of Biology, Creighton University, Omaha, Nebraska, 68178, USA
| | | | - Emma C Baker
- Department of Biology, Creighton University, Omaha, Nebraska, 68178, USA
| | - Richard Nguyen
- Department of Biology, Creighton University, Omaha, Nebraska, 68178, USA
| | - Dayton S Oki
- Department of Biology, Creighton University, Omaha, Nebraska, 68178, USA
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Becker A. A molecular update on the origin of the carpel. CURRENT OPINION IN PLANT BIOLOGY 2020; 53:15-22. [PMID: 31622798 DOI: 10.1016/j.pbi.2019.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/16/2019] [Accepted: 08/27/2019] [Indexed: 05/29/2023]
Abstract
Carpels, the female reproductive organs of flowering plants, are of major economic importance since much of our food is ultimately derived from carpel tissue and they are a defining innovation for flowering plants. Amazingly, little is known about the origin and conservation of the developmental program of the carpel besides the knowledge generated by utilizing Arabidopsis thaliana. However, in the past few years advances in ancestral state reconstruction, developmental genetics, and phylogenetic analyses led to advances in the field of flower evodevo. Here, I summarize recent work on ancestral state reconstructions of carpels, and the functions of the major components of the genetic networks governing carpel development described for Arabidopsis. Then, I point out how the stepwise addition of genes during land plant evolution has generated the A. thaliana carpel's developmental toolkit. By merging these observations, I propose a basic version of the ancestral angiosperm carpel developmental network.
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Affiliation(s)
- Annette Becker
- Justus-Liebig-University, Department of Biology and Chemistry, Institute of Botany, Heinrich-Buff-Ring 38, 35392 Gießen, Germany.
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27
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Westermann J, Streubel S, Franck CM, Lentz R, Dolan L, Boisson-Dernier A. An Evolutionarily Conserved Receptor-like Kinases Signaling Module Controls Cell Wall Integrity During Tip Growth. Curr Biol 2019; 29:3899-3908.e3. [PMID: 31679933 DOI: 10.1016/j.cub.2019.09.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/29/2019] [Accepted: 09/26/2019] [Indexed: 02/02/2023]
Abstract
Rooting cells and pollen tubes-key adaptative innovations that evolved during the colonization and subsequent radiation of plants on land-expand by tip growth. Tip growth relies on a tight coordination between the protoplast growth and the synthesis/remodeling of the external cell wall. In root hairs and pollen tubes of the seed plant Arabidopsis thaliana, cell wall integrity (CWI) mechanisms monitor this coordination through the Malectin-like receptor kinases (MLRs), such as AtANXUR1 and AtFERONIA, that act upstream of the AtMARIS PTI1-like kinase. Here, we show that rhizoid growth in the early diverging plant, Marchantia polymorpha, is also controlled by an MLR and PTI1-like signaling module. Rhizoids, root hairs, and pollen tubes respond similarly to disruption of MLR and PTI1-like encoding genes. Thus, the MLR and PTI1-like signaling module that controls CWI during tip growth is conserved between M. polymorpha and A. thaliana, suggesting that it was active in the common ancestor of land plants.
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Affiliation(s)
| | - Susanna Streubel
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | | | - Roswitha Lentz
- University of Cologne, Biocenter, 50674 Cologne, Germany
| | - Liam Dolan
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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28
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Reese JB, Williams JH. How does genome size affect the evolution of pollen tube growth rate, a haploid performance trait? AMERICAN JOURNAL OF BOTANY 2019; 106:1011-1020. [PMID: 31294836 DOI: 10.1002/ajb2.1326] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 04/17/2019] [Indexed: 06/09/2023]
Abstract
PREMISE Male gametophytes of most seed plants deliver sperm to eggs via a pollen tube. Pollen tube growth rates (PTGRs) of angiosperms are exceptionally rapid, a pattern attributed to more effective haploid selection under stronger pollen competition. Paradoxically, whole genome duplication (WGD) has been common in angiosperms but rare in gymnosperms. Pollen tube polyploidy should initially accelerate PTGR because increased heterozygosity and gene dosage should increase metabolic rates. However, polyploidy should also independently increase tube cell size, causing more work which should decelerate growth. We asked how genome size changes have affected the evolution of seed plant PTGRs. METHODS We assembled a phylogenetic tree of 451 species with known PTGRs. We then used comparative phylogenetic methods to detect effects of neo-polyploidy (within-genus origins), DNA content, and WGD history on PTGR, and correlated evolution of PTGR and DNA content. RESULTS Gymnosperms had significantly higher DNA content and slower PTGR optima than angiosperms, and their PTGR and DNA content were negatively correlated. For angiosperms, 89% of model weight favored Ornstein-Uhlenbeck models with a faster PTGR optimum for neo-polyploids, whereas PTGR and DNA content were not correlated. For within-genus and intraspecific-cytotype pairs, PTGRs of neo-polyploids < paleo-polyploids. CONCLUSIONS Genome size increases should negatively affect PTGR when genetic consequences of WGDs are minimized, as found in intra-specific autopolyploids (low heterosis) and gymnosperms (few WGDs). But in angiosperms, the higher PTGR optimum of neo-polyploids and non-negative PTGR-DNA content correlation suggest that recurrent WGDs have caused substantial PTGR evolution in a non-haploid state.
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Affiliation(s)
- John B Reese
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, 37996, U.S.A
| | - Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, 37996, U.S.A
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29
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Breygina M, Maksimov N, Polevova S, Evmenyeva A. Bipolar pollen germination in blue spruce (Picea pungens). PROTOPLASMA 2019; 256:941-949. [PMID: 30788602 DOI: 10.1007/s00709-018-01333-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
Direct growth of a pollen tube is an effective mechanism of sperm delivery characteristic for the majority of seed plants. In most cases, only one tube grows from one grain to perform the delivery function; meanwhile in Picea the appearance of two tubes from a single pollen grain is quite common during in vitro germination. Here, we describe the phenomenon of bipolar germination and test two hypotheses on its nature and possible role in gametophyte functioning. The hypothesis on "trophic" function of multiple tubes provoked by poor nutrition discussed in literature was not confirmed by in vitro growth tests; bipolar germination strongly decreased with lowering sucrose availability. The highest proportion of bipolar germination occurred in optimal conditions. We then assumed that bipolar germination occurs because turgor pressure is a non-directional force and effective systems of cell wall mechanical regulation are lacking. In hypertonic medium, bipolar germination was sufficiently lower than in isotonic medium, which was consistent with prediction of the «mechanical» hypothesis. Scanning electron microscopy and fluorescence microscopy analysis of pollen morphology and cell wall dynamics during both types of germination showed that the appearance of a single tube or bipolar germination depends on the extension of exine rupture. Cell wall softening by short-term ·OH treatment sufficiently decreased the percent of bipolar germination without affecting total germination efficiency. We concluded that mechanical properties of the cell wall and turgor pressure could shift the balance towards one of the germination patterns.
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Affiliation(s)
- M Breygina
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia.
| | - N Maksimov
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia
| | - S Polevova
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia
| | - A Evmenyeva
- Lomonosov Moscow State University, Russian Federation, Moscow, 119991, Russia
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Dehors J, Mareck A, Kiefer-Meyer MC, Menu-Bouaouiche L, Lehner A, Mollet JC. Evolution of Cell Wall Polymers in Tip-Growing Land Plant Gametophytes: Composition, Distribution, Functional Aspects and Their Remodeling. FRONTIERS IN PLANT SCIENCE 2019; 10:441. [PMID: 31057570 PMCID: PMC6482432 DOI: 10.3389/fpls.2019.00441] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/22/2019] [Indexed: 05/22/2023]
Abstract
During evolution of land plants, the first colonizing species presented leafy-dominant gametophytes, found in non-vascular plants (bryophytes). Today, bryophytes include liverworts, mosses, and hornworts. In the first seedless vascular plants (lycophytes), the sporophytic stage of life started to be predominant. In the seed producing plants, gymnosperms and angiosperms , the gametophytic stage is restricted to reproduction. In mosses and ferns, the haploid spores germinate and form a protonema, which develops into a leafy gametophyte producing rhizoids for anchorage, water and nutrient uptakes. The basal gymnosperms (cycads and Ginkgo) reproduce by zooidogamy. Their pollen grains develop a multi-branched pollen tube that penetrates the nucellus and releases flagellated sperm cells that swim to the egg cell. The pollen grain of other gymnosperms (conifers and gnetophytes) as well as angiosperms germinates and produces a pollen tube that directly delivers the sperm cells to the ovule (siphonogamy). These different gametophytes, which are short or long-lived structures, share a common tip-growing mode of cell expansion. Tip-growth requires a massive cell wall deposition to promote cell elongation, but also a tight spatial and temporal control of the cell wall remodeling in order to modulate the mechanical properties of the cell wall. The growth rate of these cells is very variable depending on the structure and the species, ranging from very slow (protonemata, rhizoids, and some gymnosperm pollen tubes), to a slow to fast-growth in other gymnosperms and angiosperms. In addition, the structural diversity of the female counterparts in angiosperms (dry, semi-dry vs wet stigmas, short vs long, solid vs hollow styles) will impact the speed and efficiency of sperm delivery. As the evolution and diversity of the cell wall polysaccharides accompanied the diversification of cell wall structural proteins and remodeling enzymes, this review focuses on our current knowledge on the biochemistry, the distribution and remodeling of the main cell wall polymers (including cellulose, hemicelluloses, pectins, callose, arabinogalactan-proteins and extensins), during the tip-expansion of gametophytes from bryophytes, pteridophytes (lycophytes and monilophytes), gymnosperms and the monocot and eudicot angiosperms.
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Abstract
With the origin of pollination in ancient seed plants, the male gametophyte ("pollen") began to evolve a new and unique life history stage, the progamic phase, a post-pollination period in which pollen sexual maturation occurs in interaction with sporophyte-derived tissues. Pollen performance traits mediate the timing of the fertilization process, often in competition with other pollen, via the speed of pollen germination, sperm development, and pollen tube growth. Studies of pollen development rarely address the issue of performance or its evolution, which involves linking variation in developmental rates to relative fitness within populations or to adaptations on a macroevolutionary scale. Modifications to the pollen tube pathway and changes in the intensity of pollen competition affect the direction and strength of selection on pollen performance. Hence, pollen developmental evolution is always contextual-it involves both the population biology of pollen reaching stigmas and the co-evolution of sporophytic traits, such as the pollen tube pathway and mating system. For most species, performance evolution generally reflects a wandering history of periods of directional selection and relaxed selection, channeled by developmental limitations, a pattern that favors the accumulation of diversity and redundancy in developmental mechanisms and the genetic machinery. Developmental biologists are focused on finding universal mechanisms that underlie pollen function, and these are largely mechanisms that have evolved through their effects on performance. Here, we suggest ways in which studies of pollen performance or function could progress by cross-fertilization between the "evo" and "devo" fields.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States.
| | - John B Reese
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, United States
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Abstract
The reproductive adaptations of land plants have played a key role in their terrestrial colonization and radiation. This encompasses mechanisms used for the production, dispersal and union of gametes to support sexual reproduction. The production of small motile male gametes and larger immotile female gametes (oogamy) in specialized multicellular gametangia evolved in the charophyte algae, the closest extant relatives of land plants. Reliance on water and motile male gametes for sexual reproduction was retained by bryophytes and basal vascular plants, but was overcome in seed plants by the dispersal of pollen and the guided delivery of non-motile sperm to the female gametes. Here we discuss the evolutionary history of male gametogenesis in streptophytes (green plants) and the underlying developmental biology, including recent advances in bryophyte and angiosperm models. We conclude with a perspective on research trends that promise to deliver a deeper understanding of the evolutionary and developmental mechanisms of male gametogenesis in plants.
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Affiliation(s)
- Dieter Hackenberg
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.
| | - David Twell
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom.
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Golgi-localized LOT regulates trans-Golgi network biogenesis and pollen tube growth. Proc Natl Acad Sci U S A 2018; 115:12307-12312. [PMID: 30413616 DOI: 10.1073/pnas.1809206115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The trans-Golgi network (TGN) is an essential tubular-vesicular organelle derived from the Golgi and functions as an independent sorting and trafficking hub within the cell. However, the molecular regulation of TGN biogenesis remains enigmatic. Here we identified an Arabidopsis mutant loss of TGN (lot) that is defective in TGN formation and sterile due to impaired pollen tube growth in the style. The mutation leads to overstacking of the Golgi cisternae and significant reduction in the number of TGNs and vesicles surrounding the Golgi in pollen, which is corroborated by the dispersed cytosolic distribution of TGN-localized proteins. Consistently, deposition of extracellular pectin and plasma membrane localization of kinases and phosphoinositide species are also impaired. Subcellular localization analysis suggests that LOT is localized on the periphery of the Golgi cisternae, but the mutation does not affect the localization of Golgi-resident proteins. Furthermore, the yeast complementation result suggests that LOT could functionally act as a component of the guanine nucleotide exchange factor (GEF) complex of small Rab GTPase Ypt6. Taken together, these findings suggest that LOT is a critical player for TGN biogenesis in the plant lineage.
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Frare R, Ayub N, Alleva K, Soto G. The Ammonium Channel NOD26 is the Evolutionary Innovation that Drives the Emergence, Consolidation, and Dissemination of Nitrogen-Fixing Symbiosis in Angiosperms. J Mol Evol 2018; 86:554-565. [DOI: 10.1007/s00239-018-9867-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/12/2018] [Indexed: 12/01/2022]
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Nadarajan J, Benson EE, Xaba P, Harding K, Lindstrom A, Donaldson J, Seal CE, Kamoga D, Agoo EMG, Li N, King E, Pritchard HW. Comparative Biology of Cycad Pollen, Seed and Tissue - A Plant Conservation Perspective. THE BOTANICAL REVIEW; INTERPRETING BOTANICAL PROGRESS 2018; 84:295-314. [PMID: 30174336 PMCID: PMC6105234 DOI: 10.1007/s12229-018-9203-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Cycads are the most endangered of plant groups based on IUCN Red List assessments; all are in Appendix I or II of CITES, about 40% are within biodiversity 'hotspots,' and the call for action to improve their protection is long-standing. We contend that progress in this direction will not be made until there is better understanding of cycad pollen, seed and tissue biology, which at the moment is limited to relatively few (<10%) species. We review what is known about germplasm (seed and pollen) storage and germination, together with recent developments in the application of contemporary technologies to tissues, such as isotype labelling, biomolecular markers and tissue culture. Whilst progress is being made, we conclude that an acceleration of comparative studies is needed to facilitate the integration of in situ and ex situ conservation programmes to better safeguard endangered cycads.
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Affiliation(s)
- J. Nadarajan
- Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN UK
- Present Address: The New Zealand Institute for Plant & Food Research Ltd, Private Bag 11600, Palmerston North, 4442 New Zealand
| | - E. E. Benson
- Damar Research Scientists, Damar, Cuparmuir, Fife, KY15 5RJ UK
| | - P. Xaba
- South African National Biodiversity Institute, Kirstenbosch National Botanical Garden, Cape Town, Republic of South Africa
| | - K. Harding
- Damar Research Scientists, Damar, Cuparmuir, Fife, KY15 5RJ UK
| | - A. Lindstrom
- Nong Nooch Tropical Botanical Garden, Chonburi, 20250 Thailand
| | - J. Donaldson
- South African National Biodiversity Institute, Kirstenbosch National Botanical Garden, Cape Town, Republic of South Africa
| | - C. E. Seal
- Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN UK
| | - D. Kamoga
- Joint Ethnobotanical Research Advocacy, P.O.Box 27901, Kampala, Uganda
| | | | - N. Li
- Fairy Lake Botanic Garden, Shenzhen, Guangdong People’s Republic of China
| | - E. King
- UNEP-World Conservation Monitoring Centre, Cambridge, UK
| | - H. W. Pritchard
- Royal Botanic Gardens, Kew, Wakehurst Place, Ardingly, West Sussex RH17 6TN UK
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Parrotta L, Faleri C, Del Duca S, Cai G. Depletion of sucrose induces changes in the tip growth mechanism of tobacco pollen tubes. ANNALS OF BOTANY 2018; 122:23-43. [PMID: 29659664 PMCID: PMC6025209 DOI: 10.1093/aob/mcy043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 03/09/2018] [Indexed: 05/24/2023]
Abstract
Background and Aims Pollen tubes are rapidly growing, photosynthetically inactive cells that need high rates of energy to support growth. Energy can derive from internal and external storage sources. The lack of carbon sources can cause various problems during pollen tube growth, which in turn could affect the reproduction of plants. Methods We analysed the effects of energy deficiency on the development of Nicotiana tabacum pollen tubes by replacing sucrose with glycerol in the growth medium. We focused on cell growth and related processes, such as metabolite composition and cell wall synthesis. Key Results We found that the lack of sucrose affects pollen germination and pollen tube length during a specific growth period. Both sugar metabolism and ATP concentration were affected by sucrose shortage when pollen tubes were grown in glycerol-based media; this was related to decreases in the concentrations of glucose, fructose and UDP-glucose. The intracellular pH and ROS levels also showed a different distribution in pollen tubes grown in sucrose-depleted media. Changes were also observed at the cell wall level, particularly in the content and distribution of two enzymes related to cell wall synthesis (sucrose synthase and callose synthase). Furthermore, both callose and newly secreted cell wall material (mainly pectins) showed an altered distribution corresponding to the lack of oscillatory growth in pollen tubes. Growth in glycerol-based media also temporarily affected the movement of generative cells and, in parallel, the deposition of callose plugs. Conclusion Pollen tubes represent an ideal model system for studying metabolic pathways during the growth of plant cells. In our study, we found evidence that glycerol, a less energetic source for cell growth than sucrose, causes critical changes in cell wall deposition. The evidence that different aspects of pollen tube growth are affected is an indication that pollen tubes adapt to metabolic stress.
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Affiliation(s)
- Luigi Parrotta
- Dipartimento Scienze della Vita, Università di Siena, Siena, Italy
| | - Claudia Faleri
- Dipartimento Scienze della Vita, Università di Siena, Siena, Italy
| | - Stefano Del Duca
- Dipartimento Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Bologna, Italy
| | - Giampiero Cai
- Dipartimento Scienze della Vita, Università di Siena, Siena, Italy
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Losada JM, Hormaza JI, Lora J. Pollen-pistil interaction in pawpaw ( Asimina triloba), the northernmost species of the mainly tropical family Annonaceae. AMERICAN JOURNAL OF BOTANY 2017; 104:1891-1903. [PMID: 29217674 DOI: 10.3732/ajb.1700319] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 10/23/2017] [Indexed: 05/24/2023]
Abstract
PREMISE OF THE STUDY The pawpaw, Asimina triloba, is an underutilized fruit crop native to North America that belongs to the mainly tropical, early-divergent family Annonaceae. Asimina is the only genus within the Annonaceae with species adapted to cold climates. A thorough analysis of its reproductive biology, specifically pollen-pistil interaction during the progamic phase, is essential to understand both its adaptation to cold climates and how to optimize its fertilization and fruit set. METHODS We characterized pollen-pistil interaction in Asimina triloba, including the floral cycle and anatomy, stigmatic receptivity, and the pollen tube pathway. We used a combination of histological, cytological, and immunolocalization approaches. KEY RESULTS Asimina triloba has a gynoecium formed by plicate carpels with a short stylar canal. Unicellular papillae form a continuous tissue covered by a copious secretion from the stigma to the ovary, which is most prominent on the stigma surface where it forms an extragynoecial compitum. Compared to the stigmas of other species in the Annonaceae, the stigmas of A. triloba show a long stigmatic receptivity associated with a long flowering cycle. Stigmatic receptivity is concomitant with the secretion of cell-wall-related arabinogalactan proteins (AGPs). CONCLUSIONS A long female phase with a long period of stigmatic receptivity is unusual among protogynous flowers of the magnoliid clade, suggesting a derived condition of A. triloba within the Annonaceae. This phase further correlates with the presence of cell-wall-related arabinogalactan proteins in the secretion, which may indicate the conservation of these glycoproteins during stigmatic receptivity and pollen tube growth in angiosperms.
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Affiliation(s)
- Juan M Losada
- Arnold Arboretum of Harvard University, 1300 Centre Street, Boston, Massachusetts 02131 USA
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138 USA
- Department of Ecology and Evolutionary Biology, Brown University, 80 Waterman Street, Providence, Rhode Island 02912 USA
| | - Jose I Hormaza
- Department of Subtropical Fruit Crops, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM La Mayora-UMA-CSIC) 29750 Algarrobo-Costa, Málaga, Spain
| | - Jorge Lora
- Department of Subtropical Fruit Crops, Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora" (IHSM La Mayora-UMA-CSIC) 29750 Algarrobo-Costa, Málaga, Spain
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Záveská Drábková L, Honys D. Evolutionary history of callose synthases in terrestrial plants with emphasis on proteins involved in male gametophyte development. PLoS One 2017; 12:e0187331. [PMID: 29131847 PMCID: PMC5683620 DOI: 10.1371/journal.pone.0187331] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 10/17/2017] [Indexed: 11/30/2022] Open
Abstract
Callose is a plant-specific polysaccharide (β-1,3-glucan) playing an important role in angiosperms in many developmental processes and responses to biotic and abiotic stresses. Callose is synthesised at the plasma membrane of plant cells by callose synthase (CalS) and, among others, represents the main polysaccharide in the callose wall surrounding the tetrads of developing microspores and in the growing pollen tube wall. CalS proteins involvement in spore development is a plesiomorphic feature of terrestrial plants, but very little is known about their evolutionary origin and relationships amongst the members of this protein family. We performed thorough comparative analyses of callose synthase family proteins from major plant lineages to determine their evolutionary history across the plant kingdom. A total of 1211 candidate CalS sequences were identified and compared amongst diverse taxonomic groups of plants, from bryophytes to angiosperms. Phylogenetic analyses identified six main clades of CalS proteins and suggested duplications during the evolution of specialised functions. Twelve family members had previously been identified in Arabidopsis thaliana. We focused on five CalS subfamilies directly linked to pollen function and found that proteins expressed in pollen evolved twice. CalS9/10 and CalS11/12 formed well-defined clades, whereas pollen-specific CalS5 was found within subfamilies that mostly did not express in mature pollen vegetative cell, although were found in sperm cells. Expression of five out of seven mature pollen-expressed CalS genes was affected by mutations in bzip transcription factors. Only three subfamilies, CalS5, CalS10, and CalS11, however, formed monophyletic, mostly conserved clades. The pairs CalS9/CalS10, CalS11/CalS12 and CalS3 may have diverged after angiosperms diversified from lycophytes and bryophytes. Our analysis of fully sequenced plant proteins identified new evolutionary lineages of callose synthase subfamilies and has established a basis for understanding their functional evolution in terrestrial plants.
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Affiliation(s)
- Lenka Záveská Drábková
- Laboratory of Pollen Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, Praha 6, Czech Republic
- * E-mail: (LZD); (DH)
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Rozvojová 263, Praha 6, Czech Republic
- * E-mail: (LZD); (DH)
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Baena-Díaz F, Fornoni J, Sosenski P, Weller SG, Domínguez CA. Pollen and stigma size changes during the transition from tristyly to distyly in Oxalis alpina (Oxalidaceae). PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:994-1002. [PMID: 28834046 DOI: 10.1111/plb.12615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/17/2017] [Indexed: 06/07/2023]
Abstract
Pollen and stigma size have the potential to influence male fitness of hermaphroditic plants, particularly in species presenting floral polymorphisms characterised by marked differences in these traits among floral morphs. In this study, we take advantage of the evolutionary transition from tristyly to distyly experienced by Oxalis alpina (Oxalidaceae), and examined whether modifications in the ancillary traits (pollen and stigma size) respond to allometric changes in other floral traits. Also, we tested whether these modifications are in accordance with what would be expected under the hypothesis that novel competitive scenarios (as in distylous-derived reproductive system) exert morph- and whorl-specific selective pressures to match the available stigmas. We measure pollen and stigma size in five populations of O. alpina representing the tristyly-distyly transition. A general reduction in pollen and stigma size occurred along the tristyly-distyly transition, and pollen size from the two anther levels within each morph converged to a similar size that was characterised by whorl-specific changes (increases or decreases) in pollen size of different anthers in each floral type. Overall, results from this study show that the evolution of distyly in this species is characterised not only by changes in sexual organ position and flower size, but also by morph-specific changes in pollen and stigma size. This evidence supports the importance of selection on pollen and stigma size, which increase fitness of remaining morphs following the evolution of distyly, and raises questions to explore on the functional value of pollen size in heterostylous systems under pollen competition.
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Affiliation(s)
- F Baena-Díaz
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - J Fornoni
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - P Sosenski
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - S G Weller
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
| | - C A Domínguez
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Nebenführ A. How to Grow a Cell: Fine-Tuning Secretory Activity to Balance Growth and Cell Wall Integrity. PLANT PHYSIOLOGY 2017; 174:3-4. [PMID: 28461398 PMCID: PMC5411154 DOI: 10.1104/pp.17.00473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An unusual exocyst subunit appears to function as a novel rheostat controlling cell growth rates.
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Affiliation(s)
- Andreas Nebenführ
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996-0840
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41
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Liu S, Liu H, Feng S, Lin M, Xu F, Lu TJ. Fountain streaming contributes to fast tip-growth through regulating the gradients of turgor pressure and concentration in pollen tubes. SOFT MATTER 2017; 13:2919-2927. [PMID: 28352884 DOI: 10.1039/c6sm01915c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Fountain streaming is a typical microfluidic pattern in plant cells, especially for cells with a high aspect ratio such as pollen tubes. Although it has been found that fountain streaming plays crucial roles in the transport of nutrients and metabolites, the positioning of organelles and the mixing of cytoplasms, its implications for the fast tip growth of pollen tubes remain a mystery. To address this, based on the observations of asiatic lily Lilium Casablanca, we developed physical models for reverse fountain streaming in pollen tubes and solved the hydrodynamics and advection-diffusion dynamics of viscous Stokes flow in the shank and apical region of pollen tubes. Theoretical and numerical results demonstrated that the gradients of turgor pressure and concentration of wall materials along the length of pollen tubes provide undamped driving force and high-efficiency materials supply, which are supposed to contribute to the fast tip-growth of pollen tubes. The sample experimental results show that the tip-growth will be abnormal when the gradients of turgor pressure change under osmotic stress induced by different concentrations of PEG-6000 (a dehydrant).
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Affiliation(s)
- ShaoBao Liu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, P. R. China. and Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China.
| | - Han Liu
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China. and MOE Key Laboratory of Biomedical Information Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - ShangSheng Feng
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, P. R. China. and Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China.
| | - Min Lin
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China. and MOE Key Laboratory of Biomedical Information Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Feng Xu
- Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China. and MOE Key Laboratory of Biomedical Information Engineering, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Tian Jian Lu
- State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an 710049, P. R. China. and Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, P. R. China.
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Michard E, Simon AA, Tavares B, Wudick MM, Feijó JA. Signaling with Ions: The Keystone for Apical Cell Growth and Morphogenesis in Pollen Tubes. PLANT PHYSIOLOGY 2017; 173:91-111. [PMID: 27895207 PMCID: PMC5210754 DOI: 10.1104/pp.16.01561] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/19/2016] [Indexed: 05/18/2023]
Abstract
Ion homeostasis and signaling are crucial to regulate pollen tube growth and morphogenesis and affect upstream membrane transporters and downstream targets.
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Affiliation(s)
- Erwan Michard
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Alexander A Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Bárbara Tavares
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - Michael M Wudick
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
| | - José A Feijó
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815 (E.M., A.A.S., M.M.W., J.A.F.); and
- Instituto Gulbenkian de Ciência, Oeiras 2780-901, Portugal (B.T.)
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Pérez Di Giorgio JA, Soto GC, Muschietti JP, Amodeo G. Pollen Aquaporins: The Solute Factor. FRONTIERS IN PLANT SCIENCE 2016; 7:1659. [PMID: 27881985 PMCID: PMC5101680 DOI: 10.3389/fpls.2016.01659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 10/21/2016] [Indexed: 05/12/2023]
Abstract
In the recent years, the biophysical properties and presumed physiological role of aquaporins (AQPs) have been expanded to specialized cells where water and solute exchange are crucial traits. Complex but unique processes such as stomatal movement or pollen hydration and germination have been addressed not only by identifying the specific AQP involved but also by studying how these proteins integrate and coordinate cellular activities and functions. In this review, we referred specifically to pollen-specific AQPs and analyzed what has been assumed in terms of transport properties and what has been found in terms of their physiological role. Unlike that in many other cells, the AQP machinery in mature pollen lacks plasma membrane intrinsic proteins, which are extensively studied for their high water capacity exchange. Instead, a variety of TIPs and NIPs are expressed in pollen. These findings have altered the initial understanding of AQPs and water exchange to consider specific and diverse solutes that might be critical to sustaining pollen's success. The spatial and temporal distribution of the pollen AQPs also reflects a regulatory mechanism that allowing a properly adjusting water and solute exchange.
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Affiliation(s)
- Juliana A. Pérez Di Giorgio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Gabriela C. Soto
- Instituto de Genética Ewald A. Favret – Centro de Investigación en Ciencias Veterinarias y Agronómicas – Instituto Nacional de Tecnología Agropecuaria – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
| | - Jorge P. Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular – Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
| | - Gabriela Amodeo
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos AiresBuenos Aires, Argentina
- Instituto de Biodiversidad y Biología Experimental y Aplicada – Universidad de Buenos Aires–Consejo Nacional de Investigaciones Científicas y TécnicasBuenos Aires, Argentina
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Filamentous actin accumulates during plant cell penetration and cell wall plug formation in Phytophthora infestans. Cell Mol Life Sci 2016; 74:909-920. [PMID: 27714409 PMCID: PMC5306229 DOI: 10.1007/s00018-016-2383-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/05/2016] [Accepted: 09/28/2016] [Indexed: 10/30/2022]
Abstract
The oomycete Phytophthora infestans is the cause of late blight in potato and tomato. It is a devastating pathogen and there is an urgent need to design alternative strategies to control the disease. To find novel potential drug targets, we used Lifeact-eGFP expressing P. infestans for high resolution live cell imaging of the actin cytoskeleton in various developmental stages. Previously, we identified actin plaques as structures that are unique for oomycetes. Here we describe two additional novel actin configurations; one associated with plug deposition in germ tubes and the other with appressoria, infection structures formed prior to host cell penetration. Plugs are composed of cell wall material that is deposited in hyphae emerging from cysts to seal off the cytoplasm-depleted base after cytoplasm retraction towards the growing tip. Preceding plug formation there was a typical local actin accumulation and during plug deposition actin remained associated with the leading edge. In appressoria, formed either on an artificial surface or upon contact with plant cells, we observed a novel aster-like actin configuration that was localized at the contact point with the surface. Our findings strongly suggest a role for the actin cytoskeleton in plug formation and plant cell penetration.
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45
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Gorelick R, Carpinone J, Derraugh LJ. No universal differences between female and male eukaryotes: anisogamy and asymmetrical female meiosis. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12874] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Root Gorelick
- Department of Biology; Carleton University; 1125 Raven Road Ottawa Ontario K1S 5B6 Canada
- School of Mathematics & Statistics and Institute of Interdisciplinary Studies; Carleton University; 1125 Raven Road Ottawa Ontario K1S 5B6 Canada
| | - Jessica Carpinone
- Department of Biology; Carleton University; 1125 Raven Road Ottawa Ontario K1S 5B6 Canada
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Di Giorgio JAP, Bienert GP, Ayub ND, Yaneff A, Barberini ML, Mecchia MA, Amodeo G, Soto GC, Muschietti JP. Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana. THE PLANT CELL 2016; 28:1053-77. [PMID: 27095837 PMCID: PMC4904668 DOI: 10.1105/tpc.15.00776] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 03/22/2016] [Accepted: 04/14/2016] [Indexed: 05/18/2023]
Abstract
In flowers with dry stigmas, pollen development, pollination, and pollen tube growth require spatial and temporal regulation of water and nutrient transport. To better understand the molecular mechanisms involved in reproductive processes, we characterized NIP4;1 and NIP4;2, two pollen-specific aquaporins of Arabidopsis thaliana. NIP4;1 and NIP4;2 are paralogs found exclusively in the angiosperm lineage. Although they have 84% amino acid identity, they displayed different expression patterns. NIP4;1 has low expression levels in mature pollen, while NIP4;2 expression peaks during pollen tube growth. Additionally, NIP4;1pro:GUS flowers showed GUS activity in mature pollen and pollen tubes, whereas NIP4;2pro:GUS flowers only in pollen tubes. Single T-DNA mutants and double artificial microRNA knockdowns had fewer seeds per silique and reduced pollen germination and pollen tube length. Transport assays in oocytes showed NIP4;1 and NIP4;2 function as water and nonionic channels. We also found that NIP4;1 and NIP4;2 C termini are phosphorylated by a pollen-specific CPK that modifies their water permeability. Survival assays in yeast indicated that NIP4;1 also transports ammonia, urea, boric acid, and H2O2 Thus, we propose that aquaporins NIP4;1 and NIP4;2 are exclusive components of the reproductive apparatus of angiosperms with partially redundant roles in pollen development and pollination.
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Affiliation(s)
- Juliana Andrea Pérez Di Giorgio
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina
| | - Gerd Patrick Bienert
- Metalloid Transport Group, Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, D-06466 Gatersleben, Germany
| | - Nicolás Daniel Ayub
- Instituto de Genética Ewald A. Favret (CICVyA-INTA), Castelar, CC25 (1712) Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1033AAJ Buenos Aires, Argentina
| | - Agustín Yaneff
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA-CONICET-UBA), Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina
| | - María Laura Barberini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina
| | - Martín Alejandro Mecchia
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina
| | - Gabriela Amodeo
- Instituto de Biodiversidad y Biología Experimental y Aplicada (IBBEA-CONICET-UBA), Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina
| | - Gabriela Cynthia Soto
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina Instituto de Genética Ewald A. Favret (CICVyA-INTA), Castelar, CC25 (1712) Buenos Aires, Argentina Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1033AAJ Buenos Aires, Argentina
| | - Jorge Prometeo Muschietti
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor Torres (INGEBI-CONICET), C1428ADN Buenos Aires, Argentina Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Pabellón II, C1428EGA Buenos Aires, Argentina
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Williams JH, Edwards JA, Ramsey AJ. Economy, efficiency, and the evolution of pollen tube growth rates. AMERICAN JOURNAL OF BOTANY 2016; 103:471-483. [PMID: 26936897 DOI: 10.3732/ajb.1500264] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/08/2015] [Indexed: 06/05/2023]
Abstract
PREMISE Pollen tube growth rate (PTGR) is an important aspect of male gametophyte performance because of its central role in the fertilization process. Theory suggests that under intense competition, PTGRs should evolve to be faster, especially if PTGR accurately reflects gametophyte quality. Oddly, we know remarkably little about how effectively the work of tube construction is translated to elongation (growth and growth rate). Here we test the prediction that pollen tubes grow equally efficiently by comparing the scaling of wall production rate (WPR) to PTGR in three water lilies that flower concurrently: Nymphaea odorata, Nuphar advena and Brasenia schreberi. METHODS Single-donor pollinations on flower or carpel pairs were fixed just after pollen germination (time A) and 45 min later (time B). Mean PTGR was calculated as the average increase in tube length over that growth period. Tube circumferences (C) and wall thicknesses (W) were measured at time B. For each donor, WPR = mean (C × W) × mean PTGR. KEY RESULTS Within species, pollen tubes maintained a constant WPR to PTGR ratio, but species had significantly different ratios. N. odorata and N. advena had similar PTGRs, but for any given PTGR, they had the lowest and highest WPRs, respectively. CONCLUSIONS We showed that growth rate efficiencies evolved by changes in the volume of wall material used for growth and in how that material was partitioned between lateral and length dimensions. The economics of pollen tube growth are determined by tube design, which is consequent on trade-offs between efficient growth and other pollen tube functions.
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Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
| | - Jacob A Edwards
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
| | - Adam J Ramsey
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee 37996 USA
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Swanson RJ, Hammond AT, Carlson AL, Gong H, Donovan TK. Pollen performance traits reveal prezygotic nonrandom mating and interference competition in Arabidopsis thaliana. AMERICAN JOURNAL OF BOTANY 2016; 103:498-513. [PMID: 26928008 DOI: 10.3732/ajb.1500172] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 10/01/2015] [Indexed: 06/05/2023]
Abstract
PREMISE The lack of ability to measure pollen performance traits in mixed pollinations has been a major hurdle in understanding the mechanisms of differential success of compatible pollen donors. In previous work, we demonstrated that nonrandom mating between two accessions of Arabidopsis thaliana, Columbia (Col) and Landsberg (Ler), is mediated by the male genotype. Despite these genetic insights, it was unclear at what stage of reproduction these genes were acting. Here, we used an experimental strategy that allowed us to differentiate different pollen populations in mixed pollinations to ask: (1) What pollen performance traits differed between Col and Ler accessions that direct nonrandom mating? (2) Is there evidence of interference competition? METHODS We used genetically marked pollen that can be visualized colorimetrically to quantify pollen performance of single populations of pollen in mixed pollinations. We used this and other assays to measure pollen viability, germination, tube growth, patterns of fertilization, and seed abortion. Finally, we assessed interference competition. RESULTS In mixed pollinations on Col pistils, Col pollen sired significantly more seeds than Ler pollen. Col pollen displayed higher pollen viability, faster and greater pollen germination, and faster pollen tube growth. We saw no evidence of nonrandom seed abortion. Finally, we found interference competition occurs in mixed pollinations. CONCLUSION The lack of differences in postzygotic processes coupled with direct observation of pollen performance traits indicates that nonrandom mating in Arabidopsis thaliana is prezygotic, due mostly to differential pollen germination and pollen tube growth rates. Finally, this study unambiguously demonstrates the existence of interference competition.
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Affiliation(s)
- Robert J Swanson
- Department of Biology, Valparaiso University, Valparaiso, Indiana 46383 USA
| | - Adam T Hammond
- Biophysical Sciences, The University of Chicago, Chicago, Illinois 60637 USA
| | - Ann L Carlson
- Department of Biology, Valparaiso University, Valparaiso, Indiana 46383 USA
| | - Hui Gong
- Department of Mathematics and Computer Science, Valparaiso University, Valparaiso, Indiana 46383 USA
| | - Thad K Donovan
- Smith Donovan Marketing & Communications, Chesterton, Indiana 46304 USA
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McCallum B, Chang SM. Pollen competition in style: Effects of pollen size on siring success in the hermaphroditic common morning glory, Ipomoea purpurea. AMERICAN JOURNAL OF BOTANY 2016; 103:460-70. [PMID: 26905086 DOI: 10.3732/ajb.1500211] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/12/2015] [Indexed: 05/16/2023]
Abstract
PREMISE OF THE STUDY Pollen size varies greatly among flowering plant species and has been shown to influence the delivery of sperm cells to the eggs. Relatively little is known, however, about the functional significance of within-species genetic variation in pollen size. This study tests whether pollen size influences the relative siring success of a pollen donor during in vivo pollen competition experiments. METHODS We used two groups of Ipomoea purpurea plants genetically divergent in their pollen sizes and applied equal number of pollen grains from one large-pollen and one small-pollen donor onto the same stigma. Using microsatellite genetic markers, we identified the pollen parent of each of the resulting progeny to determine the relative siring success of the competing donors. Competitions between donors of equal-sized pollen served as a control. KEY RESULTS Differences in pollen size significantly affected the relative siring success of a pollen donor; larger-grained individuals outcompeted smaller-grained competitors but not equal-sized competitors. Relative siring success, however, sometimes varied across different pollen recipients. CONCLUSIONS Pollen size can influence the relative siring success of different individuals competing on the same stigma during postpollination processes. However, other factors, such as pollen-pistil interaction and environmental conditions, are likely to influence these competitions as well.
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Affiliation(s)
- Britnie McCallum
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602 USA
| | - Shu-Mei Chang
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602 USA
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Harder LD, Aizen MA, Richards SA, Joseph MA, Busch JW. Diverse ecological relations of male gametophyte populations in stylar environments. AMERICAN JOURNAL OF BOTANY 2016; 103:484-497. [PMID: 26933012 DOI: 10.3732/ajb.1500269] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/08/2015] [Indexed: 06/05/2023]
Abstract
PREMISE OF STUDY Pollen on a stigma represents a local population of male gametophytes vying for access to female gametophytes in the associated ovary. As in most populations, density-independent and density-dependent survival depend on intrinsic characteristics of male gametophytes and environmental (pistil) conditions. These characteristics and conditions could differ among flowers, plants, populations, and species, creating diverse male-gametophyte population dynamics, which can influence seed siring and production. METHODS For nine species, we characterized the relations of both the mean and standard deviation of pollen-tube number at the style base to pollen receipt with nonlinear regression. Models represented asymptotic or peaked relations, providing information about the incidence and magnitude of facilitation and competition, the spatial and temporal characteristics of competition, and the intensity and relative timing of density-independent mortality. KEY RESULTS We infer that pollen tubes of most species competed sequentially, their tips ceasing growth if earlier tubes had depleted stylar space/resources; although two species experienced simultaneous competition. Tube success of three species revealed positive density dependence (facilitation) at low density. For at least four species, density-independent mortality preceded competition. Tube success varied mostly within plants, rather than among plants or conspecific populations. Pollen quality influenced tube success for two of three species; affecting density-independent survival in one and density-dependent performance in the other. CONCLUSIONS The diverse relations of pollen-tube success to pollen receipt evident among just nine species indicate significant contributions of the processes governing pollen germination and tube growth to the reproductive diversity of angiosperms.
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Affiliation(s)
- Lawrence D Harder
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4 Canada
| | - Marcelo A Aizen
- Laboratorio Ecotono, INIBIOMA-CONICET and Centro Regional Bariloche, Universidad Nacional del Comahue, Quintral 1250, 8400 Bariloche, Río Negro, Argentina
| | | | - Michael A Joseph
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, Washington 99164-4236 USA
| | - Jeremiah W Busch
- School of Biological Sciences, Washington State University, PO Box 644236, Pullman, Washington 99164-4236 USA
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