1
|
Wu H, Xie D, Jia P, Tang Z, Shi D, Shui G, Wang G, Yang W. Homeostasis of flavonoids and triterpenoids most likely modulates starch metabolism for pollen tube penetration in rice. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:1757-1772. [PMID: 37221659 PMCID: PMC10440988 DOI: 10.1111/pbi.14073] [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: 12/14/2021] [Accepted: 04/24/2023] [Indexed: 05/25/2023]
Abstract
In angiosperms, the timely delivery of sperm cell nuclei by pollen tube (PT) to the ovule is vital for double fertilization. Penetration of PT into maternal stigma tissue is a critical step for sperm cell nuclei delivery, yet little is known about the process. Here, a male-specific and sporophytic mutant xt6, where PTs are able to germinate but unable to penetrate the stigma tissue, is reported in Oryza sativa. Through genetic study, the causative gene was identified as Chalcone synthase (OsCHS1), encoding the first enzyme in flavonoid biosynthesis. Indeed, flavonols were undetected in mutant pollen grains and PTs, indicating that the mutation abolished flavonoid biosynthesis. Nevertheless, the phenotype cannot be rescued by exogenous application of quercetin and kaempferol as reported in maize and petunia, suggesting a different mechanism exists in rice. Further analysis showed that loss of OsCHS1 function disrupted the homeostasis of flavonoid and triterpenoid metabolism and led to the accumulation of triterpenoid, which inhibits significantly α-amylase activity, amyloplast hydrolysis and monosaccharide content in xt6, these ultimately impaired tricarboxylic acid (TCA) cycle, reduced ATP content and lowered the turgor pressure as well. Our findings reveal a new mechanism that OsCHS1 modulates starch hydrolysis and glycometabolism through modulating the metabolic homeostasis of flavonoids and triterpenoids which affects α-amylase activity to maintain PT penetration in rice, which contributes to a better understanding of the function of CHS1 in crop fertility and breeding.
Collapse
Affiliation(s)
- Hua‐Mao Wu
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
- State Key Laboratory of Vegetable BiobreedingInstitute of Vegetables and Flowers, Chinese Academy of Agricultural SciencesBeijingChina
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Dong‐Jiang Xie
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Peng‐Fei Jia
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Zuo‐Shun Tang
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Dong‐Qiao Shi
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Guang‐Hou Shui
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
| | - Guo‐Dong Wang
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
- State Key Laboratory of Plant GenomicsInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
| | - Wei‐Cai Yang
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijingChina
- College of Advanced Agricultural SciencesUniversity of Chinese Academy of SciencesBeijingChina
| |
Collapse
|
2
|
Goring DR, Bosch M, Franklin-Tong VE. Contrasting self-recognition rejection systems for self-incompatibility in Brassica and Papaver. Curr Biol 2023; 33:R530-R542. [PMID: 37279687 DOI: 10.1016/j.cub.2023.03.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Self-incompatibility (SI) plays a pivotal role in whether self-pollen is accepted or rejected. Most SI systems employ two tightly linked loci encoding highly polymorphic pollen (male) and pistil (female) S-determinants that control whether self-pollination is successful or not. In recent years our knowledge of the signalling networks and cellular mechanisms involved has improved considerably, providing an important contribution to our understanding of the diverse mechanisms used by plant cells to recognise each other and elicit responses. Here, we compare and contrast two important SI systems employed in the Brassicaceae and Papaveraceae. Both use 'self-recognition' systems, but their genetic control and S-determinants are quite different. We describe the current knowledge about the receptors and ligands, and the downstream signals and responses utilized to prevent self-seed set. What emerges is a common theme involving the initiation of destructive pathways that block the key processes that are required for compatible pollen-pistil interactions.
Collapse
Affiliation(s)
- Daphne R Goring
- Department of Cell & Systems Biology, University of Toronto, Toronto M5S 3B2, Canada
| | - Maurice Bosch
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3EB, Wales, UK
| | | |
Collapse
|
3
|
Chen L, Dong X, Yang H, Chai Y, Xia Y, Tian L, Qu LQ. Cytosolic disproportionating enzyme2 is essential for pollen germination and pollen tube elongation in rice. PLANT PHYSIOLOGY 2023; 191:96-109. [PMID: 36282529 PMCID: PMC9806659 DOI: 10.1093/plphys/kiac496] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/07/2022] [Indexed: 05/12/2023]
Abstract
Degradation of starch accumulated in pollen provides energy and cellular materials for pollen germination and pollen tube elongation. Little is known about the function of cytosolic disproportionating enzyme2 (DPE2) in rice (Oryza sativa). Here, we obtained several DPE2 knockout mutant (dpe2) lines via genomic editing and found that the mutants grew and developed normally but with greatly reduced seed-setting rates. Reciprocal crosses between dpe2 and wild-type plants demonstrated that the mutant was male sterile. In vitro and in vivo examinations revealed that the pollen of the dpe2 mutant developed and matured normally but was defective in germination and elongation. DPE2 deficiency increased maltose content in pollen, whereas it reduced the levels of starch, glucose, fructose, and adenosine triphosphate (ATP). Exogenous supply of glucose or ATP to the germination medium partially rescued the pollen germination defects of dpe2. The expression of cytosolic phosphorylase2 (Pho2) increased significantly in dpe2 pollen. Knockout of Pho2 resulted in a semi-sterile phenotype. We failed to obtain homozygous dpe2 pho2 double mutant lines. Our results demonstrate that maltose catalyzed by DPE2 to glucose is the main energy source for pollen germination and pollen tube elongation, while Pho2 might partially compensate for deficiency of DPE2.
Collapse
Affiliation(s)
- Liangke Chen
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangbai Dong
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China
| | - Huifang Yang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaru Chai
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Xia
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lihong Tian
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China
| | - Le Qing Qu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100093, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
4
|
Liu J, Lim SL, Zhong JY, Lim BL. Bioenergetics of pollen tube growth in Arabidopsis thaliana revealed by ratiometric genetically encoded biosensors. Nat Commun 2022; 13:7822. [PMID: 36535933 PMCID: PMC9763403 DOI: 10.1038/s41467-022-35486-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
Pollen tube is the fastest-growing plant cell. Its polarized growth process consumes a tremendous amount of energy, which involves coordinated energy fluxes between plastids, the cytosol, and mitochondria. However, how the pollen tube obtains energy and what the biological roles of pollen plastids are in this process remain obscure. To investigate this energy-demanding process, we developed second-generation ratiometric biosensors for pyridine nucleotides which are pH insensitive between pH 7.0 to pH 8.5. By monitoring dynamic changes in ATP and NADPH concentrations and the NADH/NAD+ ratio at the subcellular level in Arabidopsis (Arabidopsis thaliana) pollen tubes, we delineate the energy metabolism that underpins pollen tube growth and illustrate how pollen plastids obtain ATP, NADPH, NADH, and acetyl-CoA for fatty acid biosynthesis. We also show that fermentation and pyruvate dehydrogenase bypass are not essential for pollen tube growth in Arabidopsis, in contrast to other plant species like tobacco and lily.
Collapse
Affiliation(s)
- Jinhong Liu
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Shey-Li Lim
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Jia Yi Zhong
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Boon Leong Lim
- grid.194645.b0000000121742757School of Biological Sciences, University of Hong Kong, Hong Kong, China ,grid.194645.b0000000121742757HKU Shenzhen Institute of Research and Innovation, Shenzhen, China ,grid.10784.3a0000 0004 1937 0482State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
5
|
Ma X, Fatima M, Li J, Zhou P, Zaynab M, Ming R. Post-pollination sepal longevity of female flower co-regulated by energy-associated multiple pathways in dioecious spinach. FRONTIERS IN PLANT SCIENCE 2022; 13:1010149. [PMID: 36589106 PMCID: PMC9795224 DOI: 10.3389/fpls.2022.1010149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Reproductive growth is a bioenergetic process with high energy consumption. Pollination induces female flower longevity in spinach by accelerating sepal retention and development. Cellular bioenergetics involved in cellular growth is at the foundation of all developmental activities. By contrast, how pollination alter the sepal cells bioenergetics to support energy requirement and anabolic biomass accumulation for development is less well understood. To investigate pollination-induced energy-associated pathway changes in sepal tissues after pollination, we utilized RNA-sequencing to identify transcripts that were differentially expressed between unpollinated (UNP) and pollinated flower sepals at 12, 48, and 96HAP. In total, over 6756 non-redundant DEGs were identified followed by pairwise comparisons (i.e. UNP vs 12HAP, UNP vs 48HAP, and UNP vs 96HAP). KEGG enrichment showed that the central carbon metabolic pathway was significantly activated after pollination and governed by pivotal energy-associated regulation pathways such as glycolysis, the citric acid cycle, oxidative phosphorylation, photosynthesis, and pentose phosphate pathways. Co-expression networks confirmed the synergistically regulation interactions among these pathways. Gene expression changes in these pathways were not observed after fertilization at 12HAP, but started after fertilization at 48HAP, and significant changes in gene expression occurred at 96HAP when there is considerable sepal development. These results were also supported by qPCR validation. Our results suggest that multiple energy-associated pathways may play a pivotal regulatory role in post-pollination sepal longevity for developing the seed coat, and proposed an energy pathway model regulating sepal retention in spinach.
Collapse
Affiliation(s)
- Xiaokai Ma
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Mahpara Fatima
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jing Li
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou, China
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Ping Zhou
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, School of Future Technology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Madiha Zaynab
- Shenzhen Key Laboratory of Marine Bioresource & Eco-Environmental Sciences, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Ray Ming
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| |
Collapse
|
6
|
Wang L, Lin Z, Carli J, Gladala‐Kostarz A, Davies JM, Franklin‐Tong VE, Bosch M. Depletion plays a pivotal role in self-incompatibility, revealing a link between cellular energy status, cytosolic acidification and actin remodelling in pollen tubes. THE NEW PHYTOLOGIST 2022; 236:1691-1707. [PMID: 35775998 PMCID: PMC9796540 DOI: 10.1111/nph.18350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 06/15/2022] [Indexed: 06/08/2023]
Abstract
Self-incompatibility (SI) involves specific interactions during pollination to reject incompatible ('self') pollen, preventing inbreeding in angiosperms. A key event observed in pollen undergoing the Papaver rhoeas SI response is the formation of punctate F-actin foci. Pollen tube growth is heavily energy-dependent, yet ATP levels in pollen tubes have not been directly measured during SI. Here we used transgenic Arabidopsis lines expressing the Papaver pollen S-determinant to investigate a possible link between ATP levels, cytosolic pH ([pH]cyt ) and alterations to the actin cytoskeleton. We identify for the first time that SI triggers a rapid and significant ATP depletion in pollen tubes. Artificial depletion of ATP triggered cytosolic acidification and formation of actin aggregates. We also identify in vivo, evidence for a threshold [pH]cyt of 5.8 for actin foci formation. Imaging revealed that SI stimulates acidic cytosolic patches adjacent to the plasma membrane. In conclusion, this study provides evidence that ATP depletion plays a pivotal role in SI upstream of programmed cell death and reveals a link between the cellular energy status, cytosolic acidification and alterations to the actin cytoskeleton in regulating Papaver SI in pollen tubes.
Collapse
Affiliation(s)
- Ludi Wang
- Institute of Biological, Environmental and Rural Sciences (IBERS)Aberystwyth UniversityPlas GogerddanAberystwythSY23 3EEUK
| | - Zongcheng Lin
- Key Laboratory of Horticultural Plant BiologyHuazhong Agricultural UniversityWuhan430070China
| | - José Carli
- Institute of Biological, Environmental and Rural Sciences (IBERS)Aberystwyth UniversityPlas GogerddanAberystwythSY23 3EEUK
| | - Agnieszka Gladala‐Kostarz
- Institute of Biological, Environmental and Rural Sciences (IBERS)Aberystwyth UniversityPlas GogerddanAberystwythSY23 3EEUK
| | - Julia M. Davies
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Vernonica E. Franklin‐Tong
- School of Biosciences, College of Life and Environmental SciencesUniversity of BirminghamEdgbastonBirminghamB15 2TTUK
| | - Maurice Bosch
- Institute of Biological, Environmental and Rural Sciences (IBERS)Aberystwyth UniversityPlas GogerddanAberystwythSY23 3EEUK
| |
Collapse
|
7
|
Borghi M, Perez de Souza L, Tohge T, Mi J, Melandri G, Proost S, Martins MCM, Al-Babili S, Bouwmeester HJ, Fernie AR. High-energy-level metabolism and transport occur at the transition from closed to open flowers. PLANT PHYSIOLOGY 2022; 190:319-339. [PMID: 35640120 PMCID: PMC9434183 DOI: 10.1093/plphys/kiac253] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/29/2022] [Indexed: 06/15/2023]
Abstract
During the maturation phase of flower development, the onset of anthesis visibly marks the transition from buds to open flowers, during which petals stretch out, nectar secretion commences, and pollination occurs. Analysis of the metabolic changes occurring during this developmental transition has primarily focused on specific classes of metabolites, such as pigments and scent emission, and far less on the whole network of primary and secondary metabolites. To investigate the metabolic changes occurring at anthesis, we performed multi-platform metabolomics alongside RNA sequencing in individual florets harvested from the main inflorescence of Arabidopsis (Arabidopsis thaliana) ecotype Col-0. To trace metabolic fluxes at the level of the whole inflorescence and individual florets, we further integrated these studies with radiolabeled experiments. These extensive analyses revealed high-energy-level metabolism and transport of carbohydrates and amino acids, supporting intense metabolic rearrangements occurring at the time of this floral transition. These comprehensive data are discussed in the context of our current understanding of the metabolic shifts underlying flower opening. We envision that this analysis will facilitate the introgression of floral metabolic traits promoting pollination in crop species for which a comprehensive knowledge of flower metabolism is still limited.
Collapse
Affiliation(s)
- Monica Borghi
- Department of Biology, Utah State University, Logan, Utah 84321-5305, USA
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- Laboratory of Plant Physiology, Wageningen University and Research, Wageningen 6708 PB, The Netherlands
| | | | - Takayuki Tohge
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- Nara Institute of Science and Technology, Nara 630-0192, Japan
| | - Jianing Mi
- The Bioactives Lab, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Giovanni Melandri
- Laboratory of Plant Physiology, Wageningen University and Research, Wageningen 6708 PB, The Netherlands
- INRAE, University of Bordeaux, UMR BFP, Villenave d’Ornon 33140, France
| | - Sebastian Proost
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute, KU Leuven, Leuven, Belgium
- Center for Microbiology, VIB, Leuven 3000, Belgium
| | - Marina C M Martins
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
- In Press—Consultoria e Comunicação Científica, São Paulo 05089-030, Brazil
| | - Salim Al-Babili
- The Bioactives Lab, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | | | | |
Collapse
|
8
|
Williams JH. Consequences of whole genome duplication for 2n pollen performance. PLANT REPRODUCTION 2021; 34:321-334. [PMID: 34302535 DOI: 10.1007/s00497-021-00426-z] [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: 03/17/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
The vegetative cell of the angiosperm male gametophyte (pollen) functions as a free-living, single-celled organism that both produces and transports sperm to egg. Whole-genome duplication (WGD) should have strong effects on pollen because of the haploid to diploid transition and because of both genetic and epigenetic effects on cell-level phenotypes. To disentangle historical effects of WGD on pollen performance, studies can compare 1n pollen from diploids to neo-2n pollen from diploids and synthetic autotetraploids to older 2n pollen from established neo-autotetraploids. WGD doubles both gene number and bulk nuclear DNA mass, and a substantial proportion of diploid and autotetraploid heterozygosity can be transmitted to 2n pollen. Relative to 1n pollen, 2n pollen can exhibit heterosis due to higher gene dosage, higher heterozygosity and new allelic interactions. Doubled genome size also has consequences for gene regulation and expression as well as epigenetic effects on cell architecture. Pollen volume doubling is a universal effect of WGD, whereas an increase in aperture number is common among taxa with simultaneous microsporogenesis and pored apertures, mostly eudicots. WGD instantly affects numerous evolved compromises among mature pollen functional traits and these are rapidly shaped by highly diverse tissue interactions and pollen competitive environments in the early post-WGD generations. 2n pollen phenotypes generally incur higher performance costs, and the degree to which these are met or evolve by scaling up provisioning and metabolic vigor needs further study.
Collapse
Affiliation(s)
- Joseph H Williams
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN, 37996, USA.
| |
Collapse
|
9
|
Winship LJ, Rosen GA, Hepler PK. Apical pollen tube wall curvature correlates with growth and indicates localized changes in the yielding of the cell wall. PROTOPLASMA 2021; 258:1347-1358. [PMID: 34414478 DOI: 10.1007/s00709-021-01694-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 07/26/2021] [Indexed: 05/16/2023]
Abstract
The shape of the apical region of lily pollen tube changes rhythmically as the growth rate of the tube oscillates becoming alternately more prolate then back to oblate. We quantified shape change by calculating the curvature of the cross-sectional edge of the pollen tube tip and cross-correlating curvature changes with growth rate. The apical region takes the form of a partial elliptical spheroid, with variation in the length and location of the minor axis. During oscillation curvature profiles show a sharp increase in curvature at the "shoulders" of the apex when oblate, 4-7 μm from the flatter central zone. As the tip becomes more prolate, the "shoulders" decrease rapidly in curvature and move towards the growth axis as curvature at the tip increases. We understand curvature changes to represent differential changes in local wall expansion rates, driven by uniform turgor pressure and mediated by changes in wall polysaccharides. To become more oblate, the tip region must become less extensible than the "shoulder" region. And, as the tip becomes more prolate, the increased curvature must be due to increased local expansion. We found that changes in the growth velocity of the "shoulders" of the cell measured as the progress of the cell edge along the growth axis are cyclically out of phase with growth velocity at the tip such that the shoulder regions lag for part of the oscillation cycle, then "catch up" as the growth rate at the tip reaches a maximum and begins to decline. In this way the cell becomes oblate. Cell shape and growth rate oscillate in concert and are functionally related. Spatial change in edge growth rate points to important cellular locations for further investigation of vesicle movement and exocytosis, calcium gradients, and actin dynamics in lily pollen tubes.
Collapse
Affiliation(s)
| | - Grace A Rosen
- Hampshire College, Amherst, MA, 01002, USA
- VA Boston Healthcare System, 150 South Huntington Avenue, Boston, MA, 02130, USA
| | | |
Collapse
|
10
|
Mareri L, Faleri C, Aloisi I, Parrotta L, Del Duca S, Cai G. Insights into the Mechanisms of Heat Priming and Thermotolerance in Tobacco Pollen. Int J Mol Sci 2021; 22:8535. [PMID: 34445241 PMCID: PMC8395212 DOI: 10.3390/ijms22168535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 07/30/2021] [Accepted: 08/06/2021] [Indexed: 12/29/2022] Open
Abstract
Global warming leads to a progressive rise in environmental temperature. Plants, as sessile organisms, are threatened by these changes; the male gametophyte is extremely sensitive to high temperature and its ability to preserve its physiological status under heat stress is known as acquired thermotolerance. This latter can be achieved by exposing plant to a sub-lethal temperature (priming) or to a progressive increase in temperature. The present research aims to investigate the effects of heat priming on the functioning of tobacco pollen grains. In addition to evaluating basic physiological parameters (e.g., pollen viability, germination and pollen tube length), several aspects related to a correct pollen functioning were considered. Calcium (Ca2+) level, reactive oxygen species (ROS) and related antioxidant systems were investigated, also to the organization of actin filaments and cytoskeletal protein such as tubulin (including tyrosinated and acetylated isoforms) and actin. We also focused on sucrose synthase (Sus), a key metabolic enzyme and on the content of main soluble sugars, including UDP-glucose. Results here obtained showed that a pre-exposure to sub-lethal temperatures can positively enhance pollen performance by altering its metabolism. This can have a considerable impact, especially from the point of view of breeding strategies aimed at improving crop species.
Collapse
Affiliation(s)
- Lavinia Mareri
- Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy; (L.M.); (C.F.); (G.C.)
| | - Claudia Faleri
- Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy; (L.M.); (C.F.); (G.C.)
| | - Iris Aloisi
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy; (I.A.); (S.D.D.)
| | - Luigi Parrotta
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy; (I.A.); (S.D.D.)
- Interdepartmental Centre for Agri-Food Industrial Research, University of Bologna, Via Quinto Bucci 336, 47521 Cesena, Italy
| | - Stefano Del Duca
- Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126 Bologna, Italy; (I.A.); (S.D.D.)
- Interdepartmental Centre for Agri-Food Industrial Research, University of Bologna, Via Quinto Bucci 336, 47521 Cesena, Italy
| | - Giampiero Cai
- Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy; (L.M.); (C.F.); (G.C.)
| |
Collapse
|
11
|
Ferguson JN, Tidy AC, Murchie EH, Wilson ZA. The potential of resilient carbon dynamics for stabilizing crop reproductive development and productivity during heat stress. PLANT, CELL & ENVIRONMENT 2021; 44:2066-2089. [PMID: 33538010 DOI: 10.1111/pce.14015] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 05/20/2023]
Abstract
Impaired carbon metabolism and reproductive development constrain crop productivity during heat stress. Reproductive development is energy intensive, and its requirement for respiratory substrates rises as associated metabolism increases with temperature. Understanding how these processes are integrated and the extent to which they contribute to the maintenance of yield during and following periods of elevated temperatures is important for developing climate-resilient crops. Recent studies are beginning to demonstrate links between processes underlying carbon dynamics and reproduction during heat stress, consequently a summation of research that has been reported thus far and an evaluation of purported associations are needed to guide and stimulate future research. To this end, we review recent studies relating to source-sink dynamics, non-foliar photosynthesis and net carbon gain as pivotal in understanding how to improve reproductive development and crop productivity during heat stress. Rapid and precise phenotyping during narrow phenological windows will be important for understanding mechanisms underlying these processes, thus we discuss the development of relevant high-throughput phenotyping approaches that will allow for more informed decision-making regarding future crop improvement.
Collapse
Affiliation(s)
- John N Ferguson
- Division of Plant & Crop Science, University of Nottingham, Leicestershire, UK
- Future Food Beacon of Excellence, School of Biosciences, University of Nottingham, Leicestershire, UK
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Alison C Tidy
- Division of Plant & Crop Science, University of Nottingham, Leicestershire, UK
| | - Erik H Murchie
- Division of Plant & Crop Science, University of Nottingham, Leicestershire, UK
| | - Zoe A Wilson
- Division of Plant & Crop Science, University of Nottingham, Leicestershire, UK
| |
Collapse
|
12
|
Scali M, Moscatelli A, Bini L, Onelli E, Vignani R, Wang W. Protein Analysis of Pollen Tubes after the Treatments of Membrane Trafficking Inhibitors Gains Insights on Molecular Mechanism Underlying Pollen Tube Polar Growth. Protein J 2021; 40:205-222. [PMID: 33751342 PMCID: PMC8019430 DOI: 10.1007/s10930-021-09972-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/19/2021] [Indexed: 12/03/2022]
Abstract
Pollen tube elongation is characterized by a highly-polarized tip growth process dependent on an efficient vesicular transport system and largely mobilized by actin cytoskeleton. Pollen tubes are an ideal model system to study exocytosis, endocytosis, membrane recycling, and signaling network coordinating cellular processes, structural organization and vesicular trafficking activities required for tip growth. Proteomic analysis was applied to identify Nicotiana tabacum Differentially Abundant Proteins (DAPs) after in vitro pollen tube treatment with membrane trafficking inhibitors Brefeldin A, Ikarugamycin and Wortmannin. Among roughly 360 proteins separated in two-dimensional gel electrophoresis, a total of 40 spots visibly changing between treated and control samples were identified by MALDI-TOF MS and LC-ESI-MS/MS analysis. The identified proteins were classified according to biological processes, and most proteins were related to pollen tube energy metabolism, including ammino acid synthesis and lipid metabolism, structural features of pollen tube growth as well modification and actin cytoskeleton organization, stress response, and protein degradation. In-depth analysis of proteins corresponding to energy-related pathways revealed the male gametophyte to be a reliable model of energy reservoir and dynamics.
Collapse
Affiliation(s)
- Monica Scali
- Department of Life Sciences, University of Siena, Siena, Italy.
| | | | - Luca Bini
- Department of Life Sciences, University of Siena, Siena, Italy
| | | | - Rita Vignani
- Department of Life Sciences, University of Siena, Siena, Italy
| | - Wei Wang
- College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Lee SK, Kim H, Cho JI, Nguyen CD, Moon S, Park JE, Park HR, Huh JH, Jung KH, Guiderdoni E, Jeon JS. Deficiency of rice hexokinase HXK5 impairs synthesis and utilization of starch in pollen grains and causes male sterility. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:116-125. [PMID: 31671177 DOI: 10.1093/jxb/erz436] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/10/2019] [Indexed: 05/28/2023]
Abstract
There is little known about the function of rice hexokinases (HXKs) in planta. We characterized hxk5-1, a Tos17 mutant of OsHXK5 that is up-regulated in maturing pollen, a stage when starch accumulates. Progeny analysis of self-pollinated heterozygotes of hxk5-1 and reciprocal crosses between the wild-type and heterozygotes revealed that loss of HXK5 causes male sterility. Homozygous hxk5-1, produced via anther culture, and additional homozygous hxk5-2, hxk5-3 and hxk5-4 lines created by CRISPR/Cas9 confirmed the male-sterile phenotype. In vitro pollen germination ability and in vivo pollen tube growth rate were significantly reduced in the hxk5 mutant pollen. Biochemical analysis of anthers with the mutant pollen revealed significantly reduced hexokinase activity and starch content, although they were sufficient to produce some viable seed. However, the mutant pollen was unable to compete successfully against wild-type pollen. Expression of the catalytically inactive OsHXK5-G113D did not rescue the hxk5 male-sterile phenotype, indicating that its catalytic function was responsible for pollen fertility, rather than its role in sugar sensing and signaling. Our results demonstrate that OsHXK5 contributes to a large portion of the hexokinase activity necessary for the starch utilization pathway during pollen germination and tube growth, as well as for starch biosynthesis during pollen maturation.
Collapse
Affiliation(s)
- Sang-Kyu Lee
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Hyunbi Kim
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Jung-Il Cho
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Cong Danh Nguyen
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Sunok Moon
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Jeong Eun Park
- Department of Plant Science, Seoul National University, Seoul, Korea
| | - Hye Rang Park
- Department of Plant Science, Seoul National University, Seoul, Korea
| | - Jin Hoe Huh
- Department of Plant Science, Seoul National University, Seoul, Korea
| | - Ki-Hong Jung
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Emmanuel Guiderdoni
- CIRAD, UMR AGAP, Montpellier, France
- Université de Montpellier, CIRAD INRA Montpellier SupAgro, Montpellier, France
| | - Jong-Seong Jeon
- Graduate School of Biotechnology & Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| |
Collapse
|
15
|
Borghi M, Perez de Souza L, Yoshida T, Fernie AR. Flowers and climate change: a metabolic perspective. THE NEW PHYTOLOGIST 2019; 224:1425-1441. [PMID: 31257600 DOI: 10.1111/nph.16031] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 06/24/2019] [Indexed: 05/18/2023]
Abstract
Adverse climatic conditions at the time of flowering severely hinder crop yields and threaten the interactions between plants and their pollinators. These features depend on a common trait: the metabolism of flowers. In this Viewpoint article, we aim to provide insight into the metabolic changes that occur in flowers in response to changes in climate and emphasize that these changes severely impact the fitness of autogamous and allogamous species, plant-pollinator interactions, and overall ecosystem health. We review the biochemical processes that lead to failure of gamete development and to alterations of color, scent and nectar secretion. Then, making use of open access expression data, we examine the expression of genes that may drive these changes in response to heat and drought. Finally, we present measurements of metabolites from flowers exposed to a heat wave and discuss how the results of this short-term experiment may give rise to misleading conclusions regarding the positive effect of heat on flower fitness. We hope this article draws attention to this often-neglected dynamic and its important consequences.
Collapse
Affiliation(s)
- Monica Borghi
- Max-Planck-Institute of Molecular Plant Physiology, 14476, Potsdam-Golm, Germany
| | | | - Takuya Yoshida
- Max-Planck-Institute of Molecular Plant Physiology, 14476, Potsdam-Golm, Germany
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14476, Potsdam-Golm, Germany
| |
Collapse
|
16
|
Yi F, Gu W, Chen J, Song N, Gao X, Zhang X, Zhou Y, Ma X, Song W, Zhao H, Esteban E, Pasha A, Provart NJ, Lai J. High Temporal-Resolution Transcriptome Landscape of Early Maize Seed Development. THE PLANT CELL 2019; 31:974-992. [PMID: 30914497 PMCID: PMC6533015 DOI: 10.1105/tpc.18.00961] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/06/2019] [Accepted: 03/25/2019] [Indexed: 05/13/2023]
Abstract
The early maize (Zea mays) seed undergoes several developmental stages after double fertilization to become fully differentiated within a short period of time, but the genetic control of this highly dynamic and complex developmental process remains largely unknown. Here, we report a high temporal-resolution investigation of transcriptomes using 31 samples collected at an interval of 4 or 6 h within the first six days of seed development. These time-course transcriptomes were clearly separated into four distinct groups corresponding to the stages of double fertilization, coenocyte formation, cellularization, and differentiation. A total of 22,790 expressed genes including 1415 transcription factors (TFs) were detected in early stages of maize seed development. In particular, 1093 genes including 110 TFs were specifically expressed in the seed and displayed high temporal specificity by expressing only in particular period of early seed development. There were 160, 22, 112, and 569 seed-specific genes predominantly expressed in the first 16 h after pollination, coenocyte formation, cellularization, and differentiation stage, respectively. In addition, network analysis predicted 31,256 interactions among 1317 TFs and 14,540 genes. The high temporal-resolution transcriptome atlas reported here provides an important resource for future functional study to unravel the genetic control of seed development.
Collapse
Affiliation(s)
- Fei Yi
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Wei Gu
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
- China Specialty Maize Research Center (CIMMYT), Crop Breeding and Cultivation Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, 201403, China
| | - Jian Chen
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Ning Song
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Xiang Gao
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Xiangbo Zhang
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Yingsi Zhou
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Xuxu Ma
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Weibin Song
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Haiming Zhao
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
| | - Eddi Esteban
- Department of Cell and Systems Biology/Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario M5S 3B2, Canada
| | - Asher Pasha
- Department of Cell and Systems Biology/Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario M5S 3B2, Canada
| | - Nicholas J Provart
- Department of Cell and Systems Biology/Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Ontario M5S 3B2, Canada
| | - Jinsheng Lai
- State Key Laboratory of Agrobiotechnology and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100193, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, 100193, China
| |
Collapse
|
17
|
Flores-Herrera C, Preciado-Linares G, Gonzalez-Vizueth I, Corona de la Peña N, Gutiérrez-Aguilar M. In situ assessment of mitochondrial calcium transport in tobacco pollen tubes. PROTOPLASMA 2019; 256:503-509. [PMID: 30288611 DOI: 10.1007/s00709-018-1316-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/25/2018] [Indexed: 06/08/2023]
Abstract
Pollen tubes require functional mitochondria in order to achieve fast and sustained growth. In addition, cell wall expansion requires a calcium gradient in the tube apex formed by a dedicated array of calcium pumps and channels. Most studies have traditionally focused on the molecular aspects of calcium interactions and transport across the pollen tube plasmalemma. However, calcium transients across mitochondrial membranes from pollen tubes are beginning to be studied. Here, we report the presence of a ruthenium red-sensitive mitochondrial calcium uniporter-like activity in tobacco pollen tubes with functional oxidative phosphorylation. The present study provides a framework to measure in situ specifics of mitochondrial transport and respiration in pollen tubes from different plants. The relevance of a mitochondrial calcium uniporter for pollen tube growth is discussed.
Collapse
Affiliation(s)
- Cesar Flores-Herrera
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México City, Mexico
| | - Gisela Preciado-Linares
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México City, Mexico
| | - Israel Gonzalez-Vizueth
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México City, Mexico
| | - Norma Corona de la Peña
- Unidad de Investigación en Trombosis, Hemostasia y Aterogénesis, Hospital Carlos McGregor, México City, Mexico
| | - Manuel Gutiérrez-Aguilar
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México City, Mexico.
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Chen W, Gong P, Guo J, Li H, Li R, Xing W, Yang Z, Guan Y. Glycolysis regulates pollen tube polarity via Rho GTPase signaling. PLoS Genet 2018; 14:e1007373. [PMID: 29702701 PMCID: PMC5942846 DOI: 10.1371/journal.pgen.1007373] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 05/09/2018] [Accepted: 04/19/2018] [Indexed: 12/25/2022] Open
Abstract
As a universal energy generation pathway utilizing carbon metabolism, glycolysis plays an important housekeeping role in all organisms. Pollen tubes expand rapidly via a mechanism of polarized growth, known as tip growth, to deliver sperm for fertilization. Here, we report a novel and surprising role of glycolysis in the regulation of growth polarity in Arabidopsis pollen tubes via impingement of Rho GTPase-dependent signaling. We identified a cytosolic phosphoglycerate kinase (pgkc-1) mutant with accelerated pollen germination and compromised pollen tube growth polarity. pgkc-1 mutation greatly diminished apical exocytic vesicular distribution of REN1 RopGAP (Rop GTPase activating protein), leading to ROP1 hyper-activation at the apical plasma membrane. Consequently, pgkc-1 pollen tubes contained higher amounts of exocytic vesicles and actin microfilaments in the apical region, and showed reduced sensitivity to Brefeldin A and Latrunculin B, respectively. While inhibition of mitochondrial respiration could not explain the pgkc-1 phenotype, the glycolytic activity is indeed required for PGKc function in pollen tubes. Moreover, the pgkc-1 pollen tube phenotype was mimicked by the inhibition of another glycolytic enzyme. These findings highlight an unconventional regulatory function for a housekeeping metabolic pathway in the spatial control of a fundamental cellular process. Glycolysis, which breaks down glucose to produce energy, has long been considered a “housekeeping” pathway in living cells, i.e., it helps maintain basic cellular functions. Here, we found that the glycolysis pathway plays an unconventional regulatory role in cell polarity, i.e., the intrinsic asymmetry in the shape, structure, and organization of cellular components. Mutation in the gene encoding the glycolytic enzyme cytosolic phosphoglycerate kinase (PGKc) leads to swollen and shorter pollen tubes in Arabidopsis thaliana, which is associated with the over-activation of Rho GTPase—a master regulator of cell polarity. Our results suggest that this phenomenon is caused by a specific regulatory role of cytosolic glycolysis rather than the global energy supply or moonlighting functions of glycolytic enzymes that modulate pollen tube growth polarity. Our findings shed light on the diverse biological roles of glycolysis in plants beyond simple “housekeeping” functions.
Collapse
Affiliation(s)
- Wei Chen
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- University of Chinese Academy of Sciences, Shanghai, China
| | - Pingping Gong
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Jingzhe Guo
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Center for Plant Cell Biology, Institute of Integrated Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, California, United States of America
| | - Hui Li
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
- Center for Plant Cell Biology, Institute of Integrated Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, California, United States of America
| | - Ruizi Li
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Weiman Xing
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, China
| | - Zhenbiao Yang
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Center for Plant Cell Biology, Institute of Integrated Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, California, United States of America
| | - Yuefeng Guan
- FAFU-UCR Joint Center for Horticultural Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- * E-mail:
| |
Collapse
|
21
|
Gotelli MM, Lattar EC, Zini LM, Galati BG. Style morphology and pollen tube pathway. PLANT REPRODUCTION 2017; 30:155-170. [PMID: 29116403 DOI: 10.1007/s00497-017-0312-3] [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: 09/20/2017] [Accepted: 10/31/2017] [Indexed: 06/07/2023]
Abstract
The style morphology and anatomy vary among different species. Three basic types are: open, closed, and semi-closed. Cells involved in the pollen tube pathway in the different types of styles present abundant endoplasmic reticulum, dictyosomes, mitochondria, and ribosomes. These secretory characteristics are related to the secretion where pollen tube grows. This secretion can be represented by the substances either in the canal or in the intercellular matrix or in the cell wall. Most studies suggest that pollen tubes only grow through the secretion of the canal in open styles. However, some species present pollen tubes that penetrate the epithelial cells of the canal, or grow through the middle lamella between these cells and subepithelial cells. In species with a closed style, a pathway is provided by the presence of an extracellular matrix, or by the thickened cell walls of the stylar transmitting tissue. There are reports in some species where pollen tubes can also penetrate the transmitting tissue cells and continue their growth through the cell lumen. In this review, we define subtypes of styles according to the path of the pollen tube. Style types were mapped on an angiosperm phylogenetic tree following the maximum parsimony principle. In line with this, it could be hypothesized that: the open style appeared in the early divergent angiosperms; the closed type of style originated in Asparagales, Poales, and Eudicots; and the semi-closed style appeared in Rosids, Ericales, and Gentianales. The open style seems to have been lost in core Eudicots, with reversions in some Rosids and Asterids.
Collapse
Affiliation(s)
- M M Gotelli
- Cátedra de Botánica General, Depto. de Recursos Naturales y Ambiente, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina.
- CONICET, Buenos Aires, Argentina.
| | - E C Lattar
- IBONE-UNNE-CONICET, Corrientes, Argentina
- Cátedra de Morfología de Plantas Vasculares, Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), Corrientes, Argentina
| | - L M Zini
- IBONE-UNNE-CONICET, Corrientes, Argentina
| | - B G Galati
- Cátedra de Botánica General, Depto. de Recursos Naturales y Ambiente, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| |
Collapse
|
22
|
Borghi M, Fernie AR. Floral Metabolism of Sugars and Amino Acids: Implications for Pollinators' Preferences and Seed and Fruit Set. PLANT PHYSIOLOGY 2017; 175:1510-1524. [PMID: 28986424 PMCID: PMC5717749 DOI: 10.1104/pp.17.01164] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/04/2017] [Indexed: 05/10/2023]
Abstract
New discoveries open up future directions in the study of the primary metabolism of flowers.
Collapse
Affiliation(s)
- Monica Borghi
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| |
Collapse
|
23
|
Winship LJ, Rounds C, Hepler PK. Perturbation Analysis of Calcium, Alkalinity and Secretion during Growth of Lily Pollen Tubes. PLANTS 2016; 6:plants6010003. [PMID: 28042810 PMCID: PMC5371762 DOI: 10.3390/plants6010003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/24/2016] [Accepted: 12/26/2016] [Indexed: 01/07/2023]
Abstract
Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN) and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts; however, it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth.
Collapse
Affiliation(s)
| | - Caleb Rounds
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| |
Collapse
|
24
|
Chen Y, Zou T, McCormick S. S-Adenosylmethionine Synthetase 3 Is Important for Pollen Tube Growth. PLANT PHYSIOLOGY 2016; 172:244-53. [PMID: 27482079 PMCID: PMC5074607 DOI: 10.1104/pp.16.00774] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/30/2016] [Indexed: 05/03/2023]
Abstract
S-Adenosylmethionine is widely used in a variety of biological reactions and participates in the methionine (Met) metabolic pathway. In Arabidopsis (Arabidopsis thaliana), one of the four S-adenosylmethionine synthetase genes, METHIONINE ADENOSYLTRANSFERASE3 (MAT3), is highly expressed in pollen. Here, we show that mat3 mutants have impaired pollen tube growth and reduced seed set. Metabolomics analyses confirmed that mat3 pollen and pollen tubes overaccumulate Met and that mat3 pollen has several metabolite profiles, such as those of polyamine biosynthesis, which are different from those of the wild type. Additionally, we show that disruption of Met metabolism in mat3 pollen affected transfer RNA and histone methylation levels. Thus, our results suggest a connection between metabolism and epigenetics.
Collapse
Affiliation(s)
- Yuan Chen
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, and Department of Plant and Microbial Biology, University of California Berkeley, Albany, California 94710
| | - Ting Zou
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, and Department of Plant and Microbial Biology, University of California Berkeley, Albany, California 94710
| | - Sheila McCormick
- Plant Gene Expression Center, United States Department of Agriculture-Agricultural Research Service, and Department of Plant and Microbial Biology, University of California Berkeley, Albany, California 94710
| |
Collapse
|
25
|
Ambrosino L, Bostan H, Ruggieri V, Chiusano ML. Bioinformatics resources for pollen. PLANT REPRODUCTION 2016; 29:133-147. [PMID: 27271281 DOI: 10.1007/s00497-016-0284-8] [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: 02/10/2016] [Accepted: 05/19/2016] [Indexed: 06/06/2023]
Abstract
Bioinformatics for Pollen. Pollen plays a key role in crop production, and its development is the most delicate phase in reproduction. Different metabolic pathways are involved in pollen development, and changes in the level of some metabolites, as well as responses to stress, are correlated with the reduction in pollen viability, leading consequently to a decrease in the fruit production. However, studies on pollen may be hard because gamete development and fertilization are complex processes that occur during a short window of time. The rise of the so-called -omics sciences provided key strategies to promote molecular research in pollen tissues, starting from model organisms and moving to increasing number of species. An integrated multi-level approach based on investigations from genomics, transcriptomics, proteomics and metabolomics appears now feasible to clarify key molecular processes in pollen development and viability. To this aim, bioinformatics has a fundamental role for data production and analysis, contributing varied and ad hoc methodologies, endowed with different sensitivity and specificity, necessary for extracting added-value information from the large amount of molecular data achievable. Bioinformatics is also essential for data management, organization, distribution and integration in suitable resources. This is necessary to catch the biological features of the pollen tissues and to design effective approaches to identifying structural or functional properties, enabling the modeling of the major involved processes in normal or in stress conditions. In this review, we provide an overview of the available bioinformatics resources for pollen, ranging from raw data collections to complete databases or platforms, when available, which include data and/or results from -omics efforts on the male gametophyte. Perspectives in the fields will also be described.
Collapse
Affiliation(s)
- Luca Ambrosino
- Department of Agricultural Sciences, University of Naples "Federico II", via Università 100, Portici (NA), 80055, Italy
| | - Hamed Bostan
- Department of Agricultural Sciences, University of Naples "Federico II", via Università 100, Portici (NA), 80055, Italy
| | - Valentino Ruggieri
- Department of Agricultural Sciences, University of Naples "Federico II", via Università 100, Portici (NA), 80055, Italy
| | - Maria Luisa Chiusano
- Department of Agricultural Sciences, University of Naples "Federico II", via Università 100, Portici (NA), 80055, Italy.
| |
Collapse
|
26
|
Harder LD, Aizen MA, Richards SA. The population ecology of male gametophytes: the link between pollination and seed production. Ecol Lett 2016; 19:497-509. [DOI: 10.1111/ele.12596] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 12/18/2015] [Accepted: 02/08/2016] [Indexed: 01/07/2023]
Affiliation(s)
- Lawrence D. Harder
- Department of Biological Sciences; University of Calgary; Calgary Alberta Canada T2N 1N4
| | - Marcelo A. Aizen
- Laboratorio Ecotono; INIBIOMA-CONICET and Centro Regional Bariloche; Universidad Nacional del Comahue; Quintral 1250 8400 Bariloche Río Negro Argentina
| | - Shane A. Richards
- School of Biological and Biomedical Sciences; Durham University; South Road Durham DH1 3LE UK
| |
Collapse
|
27
|
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.
Collapse
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
| |
Collapse
|
28
|
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.
Collapse
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
| |
Collapse
|
29
|
Hepler PK. The Cytoskeleton and Its Regulation by Calcium and Protons. PLANT PHYSIOLOGY 2016; 170:3-22. [PMID: 26722019 PMCID: PMC4704593 DOI: 10.1104/pp.15.01506] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 11/28/2015] [Indexed: 05/18/2023]
Abstract
Calcium and protons exert control over the formation and activity of the cytoskeleton, usually by modulating an associated motor protein or one that affects the structural organization of the polymer.
Collapse
Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts 01003
| |
Collapse
|
30
|
Pu X, Lv X, Tan T, Fu F, Qin G, Lin H. Roles of mitochondrial energy dissipation systems in plant development and acclimation to stress. ANNALS OF BOTANY 2015; 116:583-600. [PMID: 25987710 PMCID: PMC4577992 DOI: 10.1093/aob/mcv063] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/16/2015] [Accepted: 03/27/2015] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plants are sessile organisms that have the ability to integrate external cues into metabolic and developmental signals. The cues initiate specific signal cascades that can enhance the tolerance of plants to stress, and these mechanisms are crucial to the survival and fitness of plants. The adaption of plants to stresses is a complex process that involves decoding stress inputs as energy-deficiency signals. The process functions through vast metabolic and/or transcriptional reprogramming to re-establish the cellular energy balance. Members of the mitochondrial energy dissipation pathway (MEDP), alternative oxidases (AOXs) and uncoupling proteins (UCPs), act as energy mediators and might play crucial roles in the adaption of plants to stresses. However, their roles in plant growth and development have been relatively less explored. SCOPE This review summarizes current knowledge about the role of members of the MEDP in plant development as well as recent advances in identifying molecular components that regulate the expression of AOXs and UCPs. Highlighted in particular is a comparative analysis of the expression, regulation and stress responses between AOXs and UCPs when plants are exposed to stresses, and a possible signal cross-talk that orchestrates the MEDP, reactive oxygen species (ROS), calcium signalling and hormone signalling. CONCLUSIONS The MEDP might act as a cellular energy/metabolic mediator that integrates ROS signalling, energy signalling and hormone signalling with plant development and stress accumulation. However, the regulation of MEDP members is complex and occurs at transcriptional, translational, post-translational and metabolic levels. How this regulation is linked to actual fluxes through the AOX/UCP in vivo remains elusive.
Collapse
Affiliation(s)
- Xiaojun Pu
- Ministry of Education Key Laboratory for Bio-Resource & Eco-Environment and Plant Physiology Laboratory, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| | - Xin Lv
- Ministry of Education Key Laboratory for Bio-Resource & Eco-Environment and Plant Physiology Laboratory, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| | - Tinghong Tan
- Ministry of Education Key Laboratory for Bio-Resource & Eco-Environment and Plant Physiology Laboratory, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| | - Faqiong Fu
- Ministry of Education Key Laboratory for Bio-Resource & Eco-Environment and Plant Physiology Laboratory, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| | - Gongwei Qin
- Ministry of Education Key Laboratory for Bio-Resource & Eco-Environment and Plant Physiology Laboratory, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| | - Honghui Lin
- Ministry of Education Key Laboratory for Bio-Resource & Eco-Environment and Plant Physiology Laboratory, College of Life Science, State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610064, China
| |
Collapse
|
31
|
Cai Q, Guo L, Shen ZR, Wang DY, Zhang Q. Elevation of Pollen Mitochondrial DNA Copy Number by WHIRLY2: Altered Respiration and Pollen Tube Growth in Arabidopsis. PLANT PHYSIOLOGY 2015; 169. [PMID: 26195569 PMCID: PMC4577393 DOI: 10.1104/pp.15.00437] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
In plants, the copy number of the mitochondrial DNA (mtDNA) can be much lower than the number of mitochondria. The biological significance and regulatory mechanisms of this phenomenon remain poorly understood. Here, using the pollen vegetative cell, we examined the role of the Arabidopsis (Arabidopsis thaliana) mtDNA-binding protein WHIRLY2 (AtWHY2). AtWHY2 decreases during pollen development, in parallel with the rapid degradation of mtDNA; to examine the importance of this decrease, we used the pollen vegetative cell-specific promoter Lat52 to express AtWHY2. The transgenic plants (LWHY2) had very high mtDNA levels in pollen, more than 10 times more than in the wild type (ecotype Columbia-0). LWHY2 plants were fertile, morphologically normal, and set seeds; however, reciprocal crosses with heterozygous plants showed reduced transmission of LWHY2-1 through the male and slower growth of LWHY2-1 pollen tubes. We found that LWHY2-1 pollen had significantly more reactive oxygen species and less ATP compared with the wild type, indicating an effect on mitochondrial respiration. These findings reveal that AtWHY2 affects mtDNA copy number in pollen and suggest that low mtDNA copy numbers might be the normal means by which plant cells maintain mitochondrial genetic information.
Collapse
Affiliation(s)
- Qiang Cai
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.)
| | - Liang Guo
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.)
| | - Zhao-Rui Shen
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.)
| | - Dan-Yang Wang
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.)
| | - Quan Zhang
- Key Laboratory of Ministry of Education for Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing 100871, China (Q.C., L.G., Z.-R.S., Q.Z., S.); andKey Laboratory of Ministry of Education for Resource Biology and Biotechnology in Western China, School of Life Science, Northwest University, Xi'an 710069, China (D.-Y.W.)
| |
Collapse
|
32
|
Wang W, Liu X, Gai X, Ren J, Liu X, Cai Y, Wang Q, Ren H. Cucumis sativus L. WAX2 Plays a Pivotal Role in Wax Biosynthesis, Influencing Pollen Fertility and Plant Biotic and Abiotic Stress Responses. PLANT & CELL PHYSIOLOGY 2015; 56:1339-54. [PMID: 26023108 DOI: 10.1093/pcp/pcv052] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 03/09/2015] [Indexed: 05/18/2023]
Abstract
Cuticular waxes play an important part in protecting plant aerial organs from biotic and abiotic stresses. In previous studies, the biosynthetic pathway of cuticular waxes and relative functional genes has been researched and understood; however, little is known in cucumber (Cucumis sativus L.). In this study, we cloned and characterized an AtWAX2 homolog, CsWAX2, in cucumber and found that it is highly expressed in the epidermis, where waxes are synthesized, while subcellular localization showed that CsWAX2 protein is localized to the endoplasmic reticulum (ER). The transcriptional expression of CsWAX2 was found to be induced by low temperature, drought, salt stress and ABA, while the ectopic expression of CsWAX2 in an Arabidopsis wax2 mutant could partially complement the glossy stem phenotype. Abnormal expression of CsWAX2 in transgenic cucumbers specifically affected both very long chain (VLC) alkanes and cutin biosynthesis. Furthermore, transgenic cucumber plants of CsWAX2 showed significant changes in pollen viability and fruit resistance to water loss and pathogens compared with the wild type. Collectively, these results indicated that CsWAX2 plays a pivotal role in wax biosynthesis, influencing pollen fertility and the plant's response to biotic and abiotic stresses.
Collapse
Affiliation(s)
- Wenjiao Wang
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| | - Xingwang Liu
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| | - Xinshuang Gai
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| | - Jiaojiao Ren
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| | - Xiaofeng Liu
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| | - Yanling Cai
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| | - Qian Wang
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| | - Huazhong Ren
- Department of Vegetable Science, College of Agronomy and Bio-technology, China Agricultural University, Beijing, 100193 PR China Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, China Agricultural University, Beijing, 100193 PR China
| |
Collapse
|
33
|
Gao Y, Zhou H, Chen J, Jiang X, Tao S, Wu J, Zhang S. Mitochondrial dysfunction mediated by cytoplasmic acidification results in pollen tube growth cessation in Pyrus pyrifolia. PHYSIOLOGIA PLANTARUM 2015; 153:603-15. [PMID: 25135193 DOI: 10.1111/ppl.12260] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 06/18/2014] [Accepted: 06/26/2014] [Indexed: 05/28/2023]
Abstract
The length of pollen tubes grown in synthetic media is normally shorter than those grown in vivo. However, the mechanism(s) underlying the cessation of pollen tube growth under culture conditions remain(s) largely unknown. Here, we report a previously unknown correlation between vacuolar function and the cell's ability to sustain mitochondrial functions in pear pollen tubes. The pear pollen tubes in vitro grew slowly after 15 hours post-cultured (HPC) and nearly ceased growth at 18 HPC. There was increased malondialdehyde content and membrane ion leakage at 15 HPC compared with 12 HPC. Furthermore, cytoplasmic acidification mainly mediated by decreased vacuolar H(+)-ATPase [V-ATPase, Enzyme Commission (EC) 3.6.1.3] activity was observed in pollen tubes after 15 HPC, and this further resulted in mitochondrial dysfunction, including mitochondrial structure disruption, mitochondrial membrane potential collapse and decreases in both oxygen consumption and ATP production. Our findings suggest that vacuoles and mitochondria intimately linked in regulating pollen tube elongation.
Collapse
Affiliation(s)
- Yongbin Gao
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China
| | | | | | | | | | | | | |
Collapse
|
34
|
Hepler PK, Winship LJ. The pollen tube clear zone: clues to the mechanism of polarized growth. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:79-92. [PMID: 25431342 DOI: 10.1111/jipb.12315] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 11/24/2014] [Indexed: 05/08/2023]
Abstract
Pollen tubes usually exhibit a prominent region at their apex called the "clear zone" because it lacks light refracting amyloplasts. A robust, long clear zone often associates with fast growing pollen tubes, and thus serves as an indicator of pollen tube health. Nevertheless we do not understand how it arises or how it is maintained. Here we review the structure of the clear zone, and attempt to explain the factors that contribute to its formation. While amyloplasts and vacuolar elements are excluded from the clear zone, virtually all other organelles are present including secretory vesicles, mitochondria, Golgi dictyosomes, and the endoplasmic reticulum (ER). Secretory vesicles aggregate into an inverted cone appressed against the apical plasma membrane. ER elements move nearly to the extreme apex, whereas mitochondria and Golgi dictyosomes move less far forward. The cortical actin fringe assumes a central position in the control of clear zone formation and maintenance, given its role in generating cytoplasmic streaming. Other likely factors include the tip-focused calcium gradient, the apical pH gradient, the influx of water, and a host of signaling factors (small G-proteins). We think that the clear zone is an emergent property that depends on the interaction of several factors crucial for polarized growth.
Collapse
Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, Massachusetts, 01003, USA
| | | |
Collapse
|
35
|
Cai G, Parrotta L, Cresti M. Organelle trafficking, the cytoskeleton, and pollen tube growth. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2015; 57:63-78. [PMID: 25263392 DOI: 10.1111/jipb.12289] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/23/2014] [Indexed: 06/03/2023]
Abstract
The pollen tube is fundamental for the reproduction of seed plants. Characteristically, it grows relatively quickly and uni-directionally ("polarized growth") to extend the male gametophyte to reach the female gametophyte. The pollen tube forms a channel through which the sperm cells move so that they can reach their targets in the ovule. To grow quickly and directionally, the pollen tube requires an intense movement of organelles and vesicles that allows the cell's contents to be distributed to sustain the growth rate. While the various organelles distribute more or less uniformly within the pollen tube, Golgi-released secretory vesicles accumulate massively at the pollen tube apex, that is, the growing region. This intense movement of organelles and vesicles is dependent on the dynamics of the cytoskeleton, which reorganizes differentially in response to external signals and coordinates membrane trafficking with the growth rate of pollen tubes.
Collapse
Affiliation(s)
- Giampiero Cai
- Department of Life Sciences, University of Siena, Siena, 53100, Italy
| | | | | |
Collapse
|
36
|
Liu T, Qian Y, Duan W, Ren J, Hou X, Li Y. BcRISP1, isolated from non-heading Chinese cabbage, decreases the seed set of transgenic Arabidopsis. HORTICULTURE RESEARCH 2014; 1:14062. [PMID: 26504557 PMCID: PMC4596333 DOI: 10.1038/hortres.2014.62] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/11/2014] [Accepted: 11/11/2014] [Indexed: 05/31/2023]
Abstract
Mitochondria are the energy sources of plant cells and are involved in regulating cell development. Ubiquinol-cytochrome c reductase iron-sulfur protein, which is necessary for mitochondrial respiration, is a subunit of mitochondrial electron transport chain multimeric enzyme complexes. To better understand the biological function of the ubiquinol-cytochrome c reductase iron-sulfur protein, the full-length cDNA of BcRISP1 was cloned; it was found to contain 810 base pairs and encode 269 amino acids. Unusually, high expression of the BcRISP1 gene in the archesporial cell stages was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis of cytoplasmic male sterile lines and maintainer lines. The seed set was affected by the overexpression of BcRISP1, and shorter siliques with lower seed sets were observed in 35S::BcRISP1 Arabidopsis plants. These characteristics may have resulted from the reduced formation of pollen and impaired pollen tube growth. qRT-PCR results revealed that in 35S::BcRISP1 plants, the expression levels of the mitochondrial respiratory chain-related genes, COX10 and RIP1, were enhanced, whereas the expression levels of QCR7 and SDH2-1 were reduced. This result implies that overexpression of BcRISP1 in transgenic Arabidopsis plants may disrupt the mitochondrial electron transport chain by affecting the expression of mitochondrial respiratory chain-related genes and therefore, reducing the seed set.
Collapse
Affiliation(s)
- Tongkun Liu
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- State Key Laboratory of Crop Genetics & Germplasm Enhancement, Ministry of Agriculture, Nanjing 210095, China
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, Nanjing 210095, China
| | - Yu Qian
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- State Key Laboratory of Crop Genetics & Germplasm Enhancement, Ministry of Agriculture, Nanjing 210095, China
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, Nanjing 210095, China
| | - Weike Duan
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- State Key Laboratory of Crop Genetics & Germplasm Enhancement, Ministry of Agriculture, Nanjing 210095, China
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, Nanjing 210095, China
| | - Jun Ren
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- State Key Laboratory of Crop Genetics & Germplasm Enhancement, Ministry of Agriculture, Nanjing 210095, China
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, Nanjing 210095, China
| | - Xilin Hou
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- State Key Laboratory of Crop Genetics & Germplasm Enhancement, Ministry of Agriculture, Nanjing 210095, China
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, Nanjing 210095, China
| | - Ying Li
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
- State Key Laboratory of Crop Genetics & Germplasm Enhancement, Ministry of Agriculture, Nanjing 210095, China
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, Nanjing 210095, China
| |
Collapse
|
37
|
Dumont M, Lehner A, Bouton S, Kiefer-Meyer MC, Voxeur A, Pelloux J, Lerouge P, Mollet JC. The cell wall pectic polymer rhamnogalacturonan-II is required for proper pollen tube elongation: implications of a putative sialyltransferase-like protein. ANNALS OF BOTANY 2014; 114:1177-88. [PMID: 24825296 PMCID: PMC4195553 DOI: 10.1093/aob/mcu093] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 04/01/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Rhamnogalacturonan-II (RG-II) is one of the pectin motifs found in the cell wall of all land plants. It contains sugars such as 2-keto-3-deoxy-d-lyxo-heptulosaric acid (Dha) and 2-keto-3-deoxy-d-manno-octulosonic acid (Kdo), and within the wall RG-II is mostly found as a dimer via a borate diester cross-link. To date, little is known regarding the biosynthesis of this motif. Here, after a brief review of our current knowledge on RG-II structure, biosynthesis and function in plants, this study explores the implications of the presence of a Golgi-localized sialyltransferase-like 2 (SIA2) protein that is possibly involved in the transfer of Dha or Kdo in the RG-II of Arabidopsis thaliana pollen tubes, a fast-growing cell type used as a model for the study of cell elongation. METHODS Two heterozygous mutant lines of arabidopsis (sia2-1+/- and qrt1 × sia2-2+/-) were investigated. sia2-2+/- was in a quartet1 background and the inserted T-DNA contained the reporter gene β-glucuronidase (GUS) under the pollen-specific promoter LAT52. Pollen germination and pollen tube phenotype and growth were analysed both in vitro and in vivo by microscopy. KEY RESULTS Self-pollination of heterozygous lines produced no homozygous plants in the progeny, which may suggest that the mutation could be lethal. Heterozygous mutants displayed a much lower germination rate overall and exhibited a substantial delay in germination (20 h of delay to reach 30 % of pollen grain germination compared with the wild type). In both lines, mutant pollen grains that were able to produce a tube had tubes that were either bursting, abnormal (swollen or dichotomous branching tip) or much shorter compared with wild-type pollen tubes. In vivo, mutant pollen tubes were restricted to the style, whereas the wild-type pollen tubes were detected at the base of the ovary. CONCLUSIONS This study highlights that the mutation in arabidopsis SIA2 encoding a sialyltransferase-like protein that may transfer Dha or Kdo on the RG-II motif has a dramatic effect on the stability of the pollen tube cell wall.
Collapse
Affiliation(s)
- Marie Dumont
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV) EA4358, Normandy University, University of Rouen, Institut de Recherche et d'Innovation Biomédicale, 76821 Mont-Saint-Aignan, France
| | - Arnaud Lehner
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV) EA4358, Normandy University, University of Rouen, Institut de Recherche et d'Innovation Biomédicale, 76821 Mont-Saint-Aignan, France
| | - Sophie Bouton
- Laboratoire Biologie des Plantes & Innovation (BIOPI) EA3900, University of Picardie Jules Verne, 80039 Amiens, France
| | - Marie Christine Kiefer-Meyer
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV) EA4358, Normandy University, University of Rouen, Institut de Recherche et d'Innovation Biomédicale, 76821 Mont-Saint-Aignan, France
| | - Aline Voxeur
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV) EA4358, Normandy University, University of Rouen, Institut de Recherche et d'Innovation Biomédicale, 76821 Mont-Saint-Aignan, France Institut Jean-Pierre Bourgin UMR1318 INRA-AgroParisTech, 78026 Versailles Cedex, France
| | - Jérôme Pelloux
- Laboratoire Biologie des Plantes & Innovation (BIOPI) EA3900, University of Picardie Jules Verne, 80039 Amiens, France
| | - Patrice Lerouge
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV) EA4358, Normandy University, University of Rouen, Institut de Recherche et d'Innovation Biomédicale, 76821 Mont-Saint-Aignan, France
| | - Jean-Claude Mollet
- Laboratoire de Glycobiologie et Matrice Extracellulaire Végétale (Glyco-MEV) EA4358, Normandy University, University of Rouen, Institut de Recherche et d'Innovation Biomédicale, 76821 Mont-Saint-Aignan, France
| |
Collapse
|
38
|
Rounds CM, Hepler PK, Winship LJ. The apical actin fringe contributes to localized cell wall deposition and polarized growth in the lily pollen tube. PLANT PHYSIOLOGY 2014; 166:139-51. [PMID: 25037212 PMCID: PMC4149702 DOI: 10.1104/pp.114.242974] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/08/2014] [Indexed: 05/19/2023]
Abstract
In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube.
Collapse
Affiliation(s)
- Caleb M Rounds
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003 (C.M.R., P.K.H.); andSchool of Natural Science, Hampshire College, Amherst, Massachusetts 01002 (L.J.W.)
| | - Peter K Hepler
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003 (C.M.R., P.K.H.); andSchool of Natural Science, Hampshire College, Amherst, Massachusetts 01002 (L.J.W.)
| | - Lawrence J Winship
- Department of Biology, University of Massachusetts, Amherst, Massachusetts 01003 (C.M.R., P.K.H.); andSchool of Natural Science, Hampshire College, Amherst, Massachusetts 01002 (L.J.W.)
| |
Collapse
|
39
|
Selinski J, König N, Wellmeyer B, Hanke GT, Linke V, Neuhaus HE, Scheibe R. The plastid-localized NAD-dependent malate dehydrogenase is crucial for energy homeostasis in developing Arabidopsis thaliana seeds. MOLECULAR PLANT 2014; 7:170-86. [PMID: 24198233 DOI: 10.1093/mp/sst151] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In the absence of photosynthesis, ATP is imported into chloroplasts and non-green plastids by ATP/ADP transporters or formed during glycolysis, the latter requiring continuous regeneration of NAD(+), supplied by the plastidial isoform of NAD-MDH. During screening for T-DNA insertion mutants in the plNAD-MDH gene of Arabidopsis, only heterozygous plants could be isolated and homozygous knockout mutants grew only after complementation. These heterozygous plants show higher transcript levels of an alternative NAD(+)-regenerating enzyme, NADH-GOGAT, and, remarkably, improved growth when ammonium is the sole N-source. In situ hybridization and GUS-histochemical staining revealed that plNAD-MDH was particularly abundant in male and female gametophytes. Knockout plNAD-MDH pollen exhibit impaired tube growth in vitro, which can be overcome by adding the substrates of NADH-GOGAT. In vivo, knockout pollen is able to fertilize the egg cell. Young siliques of selfed heterozygous plants contain both green and white seeds corresponding to wild-type/heterozygous (green) and homozygous knockout mutants (white) in a (1:2):1 ratio. Embryos of the homozygous knockout seeds only reached the globular stage, did not green, and developed to tiny wrinkled seeds. Complementation with the gene under the native promoter rescued this defect, and all seeds developed as wild-type. This suggests that a blocked major physiological process in plNAD-MDH mutants stops both embryo and endosperm development, thus avoiding assimilate investment in compromised offspring.
Collapse
Affiliation(s)
- Jennifer Selinski
- Department of Plant Physiology, FB 5, University of Osnabrueck, D-49069 Osnabrueck, Germany
| | | | | | | | | | | | | |
Collapse
|
40
|
Gao YB, Wang CL, Wu JY, Zhou HS, Jiang XT, Wu J, Zhang SL. Low temperature inhibits pollen tube growth by disruption of both tip-localized reactive oxygen species and endocytosis in Pyrus bretschneideri Rehd. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 74:255-62. [PMID: 24321875 DOI: 10.1016/j.plaphy.2013.11.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/15/2013] [Indexed: 05/08/2023]
Abstract
Low temperature (LT) negatively affects fertilization processes of flowering plants. Pollen tube growth is generally inhibited under LT stress; however, the mechanism(s) underlying this inhibition remain(s) largely unknown. Pollen tubes are tip-growing and the presence of tip-localized reactive oxygen species (ROS) is necessary for cellular functioning. Disruption of tip-localized ROS was observed in pear pollen tubes in vitro under low temperature of 4 °C (LT4). Diphenylene iodonium chloride, an NADPH oxidase (NOX) inhibitor, suppressed hydrogen peroxide formation in the cell walls of the subapical region in pear pollen tubes. Under LT4 stress, ROS disruption in pear pollen tubes mainly resulted from decreased NOX activity in the plasma membrane, indicating that NOX was the main source of ROS in this process. Moreover, LT4 remarkably decreased mitochondrial oxygen consumption and intracellular ATP production. The endocytosis, an energy-dependent process, disruption in pear pollen tubes under LT4 may be mediated by mitochondrial metabolic dysfunctions. Our data showed ROS and endocytosis events in pear pollen tubes responding to LT4 stress.
Collapse
Affiliation(s)
- Yong-Bin Gao
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Chun-Lei Wang
- Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiya, Aoba-ku, Sendai 981-8555, Japan
| | - Ju-You Wu
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Hong-Sheng Zhou
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Xue-Ting Jiang
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Jun Wu
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Shao-Ling Zhang
- College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
| |
Collapse
|
41
|
Selinski J, Scheibe R. Pollen tube growth: where does the energy come from? PLANT SIGNALING & BEHAVIOR 2014; 9:e977200. [PMID: 25482752 PMCID: PMC4622831 DOI: 10.4161/15592324.2014.977200] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 08/28/2014] [Indexed: 05/18/2023]
Abstract
This review focuses on the energy metabolism during pollen maturation and tube growth and updates current knowledge. Pollen tube growth is essential for male reproductive success and extremely fast. Therefore, pollen development and tube growth are high energy-demanding processes. During the last years, various publications (including research papers and reviews) emphasize the importance of mitochondrial respiration and fermentation during male gametogenesis and pollen tube elongation. These pathways obviously contribute to satisfy the high energy demand, and there are many studies which suggest that respiration and fermentation are the only pathways to generate the needed energy. Here, we review data which show for the first time that in addition plastidial glycolysis and the balancing of the ATP/NAD(P)H ratio (by malate valves and NAD(+) biosynthesis) contribute to satisfy the energy demand during pollen development. Although the importance of energy generation by plastids was discounted during the last years (possibly due to the controversial opinion about their existence in pollen grains and pollen tubes), the available data underline their prime role during pollen maturation and tube growth.
Collapse
Key Words
- 2-OG, 2-oxoglutarate
- 2-PGA, 2-phosphoglycerate
- 3-PGA, 3-phosphoglycerate
- ACS, acetyl-CoA synthase
- ADH, alcohol dehydrogenase
- ALDH, aldehyde dehydrogenase
- AOX, alternative oxidase
- BPGA, bisphosphoglyceric acid
- ENO, enolase
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GOGAT, glutamate synthase
- GPT, G-6-P/phosphate translocators
- Gln, glutamine
- Glu, glutamate
- MDH, malate dehydrogenase
- NDP, nucleotide diphosphate kinase
- NMNAT, nicotinate/nicotinamide mononucleotide adenyltransferase
- NTT, ATP/ADP transporters
- OAA, oxaloacetate
- OPP, oxidative pentose-phosphate pathway
- PDC, pyruvate decarboxylase
- PDH, pyruvate dehydrogenase
- PEP, phosphoenolpyruvate
- PGAM, phosphoglycerate mutase
- PGDH, 3-phosphoglycerate dehydrogenase
- PK, pyruvate kinase
- PPSB, phosphorylated pathway of serine biosynthesis
- PPT, phosphoenolpyruvate/phosphate translocator
- PSP, phosphoserine phosphatase
- RNS, reactive nitrogen species
- ROS, reactive oxygen species
- RPOT, T3/T7 phage-type RNA polymerases
- T, malate/oxaloacetate translocator
- TP, triose phosphate.
- energy metabolism
- malate
- plastidial glycolysis
- pollen tube growth
- respiration
Collapse
Affiliation(s)
- Jennifer Selinski
- Department of Plant Physiology; University of Osnabrueck; Osnabrueck, Germany
| | - Renate Scheibe
- Department of Plant Physiology; University of Osnabrueck; Osnabrueck, Germany
- Correspondence to: Renate Scheibe;
| |
Collapse
|
42
|
Pietruszka M. Pressure-induced cell wall instability and growth oscillations in pollen tubes. PLoS One 2013; 8:e75803. [PMID: 24260097 PMCID: PMC3833986 DOI: 10.1371/journal.pone.0075803] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 08/18/2013] [Indexed: 11/19/2022] Open
Abstract
In the seed plants, the pollen tube is a cellular extension that serves as a conduit through which male gametes are transported to complete fertilization of the egg cell. It consists of a single elongated cell which exhibits characteristic oscillations in growth rate until it finally bursts, completing its function. The mechanism behind the periodic character of the growth has not been fully understood. In this paper we show that the mechanism of pressure--induced symmetry frustration occurring in the wall at the transition-perimeter between the cylindrical and approximately hemispherical parts of the growing pollen tube, together with the addition of cell wall material, is sufficient to release and sustain mechanical self-oscillations and cell extension. At the transition zone, where symmetry frustration occurs and one cannot distinguish either of the involved symmetries, a kind of 'superposition state' appears where either single or both symmetry(ies) can be realized by the system. We anticipate that testifiable predictions made by the model (f is proportional to √P) may deliver, after calibration, a new tool to estimate turgor pressure P from oscillation frequency f of the periodically growing cell. Since the mechanical principles apply to all turgor regulated walled cells including those of plant, fungal and bacterial origin, the relevance of this work is not limited to the case of the pollen tube.
Collapse
Affiliation(s)
- Mariusz Pietruszka
- Faculty of Biology and Environment Protection, University of Silesia, Katowice, Poland
| |
Collapse
|
43
|
Basic rules for polarised cell growth. J Theor Biol 2013; 336:44-51. [DOI: 10.1016/j.jtbi.2013.06.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/25/2013] [Accepted: 06/27/2013] [Indexed: 12/11/2022]
|
44
|
Obermeyer G, Fragner L, Lang V, Weckwerth W. Dynamic adaption of metabolic pathways during germination and growth of lily pollen tubes after inhibition of the electron transport chain. PLANT PHYSIOLOGY 2013; 162:1822-33. [PMID: 23660836 PMCID: PMC3729764 DOI: 10.1104/pp.113.219857] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/08/2013] [Indexed: 05/19/2023]
Abstract
Investigation of the metabolome and the transcriptome of pollen of lily (Lilium longiflorum) gave a comprehensive overview of metabolic pathways active during pollen germination and tube growth. More than 100 different metabolites were determined simultaneously by gas chromatography coupled to mass spectrometry, and expressed genes of selected metabolic pathways were identified by next-generation sequencing of lily pollen transcripts. The time-dependent changes in metabolite abundances, as well as the changes after inhibition of the mitochondrial electron transport chain, revealed a fast and dynamic adaption of the metabolic pathways in the range of minutes. The metabolic state prior to pollen germination differed clearly from the metabolic state during pollen tube growth, as indicated by principal component analysis of all detected metabolites and by detailed observation of individual metabolites. For instance, the amount of sucrose increased during the first 60 minutes of pollen culture but decreased during tube growth, while glucose and fructose showed the opposite behavior. Glycolysis, tricarbonic acid cycle, glyoxylate cycle, starch, and fatty acid degradation were activated, providing energy during pollen germination and tube growth. Inhibition of the mitochondrial electron transport chain by antimycin A resulted in an immediate production of ethanol and a fast rearrangement of metabolic pathways, which correlated with changes in the amounts of the majority of identified metabolites, e.g. a rapid increase in γ-aminobutyric acid indicated the activation of a γ-aminobutyric acid shunt in the tricarbonic acid cycle, while ethanol fermentation compensated the reduced ATP production after inhibition of the oxidative phosphorylation.
Collapse
Affiliation(s)
- Gerhard Obermeyer
- Molecular Plant Biophysics and Biochemistry, Department of Molecular Biology, University of Salzburg, 5020 Salzburg, Austria.
| | | | | | | |
Collapse
|
45
|
Hepler PK, Rounds CM, Winship LJ. Control of cell wall extensibility during pollen tube growth. MOLECULAR PLANT 2013; 6:998-1017. [PMID: 23770837 PMCID: PMC4043104 DOI: 10.1093/mp/sst103] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In this review, we address the question of how the tip-growing pollen tube achieves its rapid rate of elongation while maintaining an intact cell wall. Although turgor is essential for growth to occur, the local expansion rate is controlled by local changes in the viscosity of the apical wall. We focus on several different structures and underlying processes that are thought to be major participants including exocytosis, the organization and activity of the actin cytoskeleton, calcium and proton physiology, and cellular energetics. We think that the actin cytoskeleton, in particular the apical cortical actin fringe, directs the flow of vesicles to the apical domain, where they fuse with the plasma membrane and contribute their contents to the expanding cell wall. While pH gradients, as generated by a proton-ATPase located on the plasma membrane along the side of the clear zone, may regulate rapid actin turnover and new polymerization in the fringe, the tip-focused calcium gradient biases secretion towards the polar axis. The recent data showing that exocytosis of new wall material precedes and predicts the process of cell elongation provide support for the idea that the intussusception of newly secreted pectin contributes to decreases in apical wall viscosity and to cell expansion. Other prime factors will be the localization and activity of the enzyme pectin methyl-esterase, and the chelation of calcium by pectic acids. Finally, we acknowledge a role for reactive oxygen species in the control of wall viscosity.
Collapse
Affiliation(s)
- Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA 01003, USA.
| | | | | |
Collapse
|
46
|
Domozych DS. The quest for four-dimensional imaging in plant cell biology: it's just a matter of time. ANNALS OF BOTANY 2012; 110:461-74. [PMID: 22628381 PMCID: PMC3394652 DOI: 10.1093/aob/mcs107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/04/2012] [Indexed: 05/22/2023]
Abstract
BACKGROUND Analysis of plant cell dynamics over time, or four-dimensional imaging (4-DI), represents a major goal of plant science. The ability to resolve structures in the third dimension within the cell or tissue during developmental events or in response to environmental or experimental stresses (i.e. 4-DI) is critical to our understanding of gene expression, post-expression modulations of macromolecules and sub-cellular system interactions. SCOPE Microscopy-based technologies have been profoundly integral to this type of investigation, and new and refined microscopy technologies now allow for the visualization of cell dynamics with unprecedented resolution, contrast and experimental versatility. However, certain realities of light and electron microscopy, choice of specimen and specimen preparation techniques limit the scope of readily attaining 4-DI. Today, the plant microscopist must use a combinatorial strategy whereby multiple microscopy-based investigations are used. Modern fluorescence, confocal laser scanning, transmission electron and scanning electron microscopy provide effective conduits for synthesizing data detailing live cell dynamics and highly resolved snapshots of specific cell structures that will ultimately lead to 4-DI. This review provides a synopsis of such technologies available.
Collapse
Affiliation(s)
- David S Domozych
- Department of Biology and Skidmore Microscopy Imaging Center, Skidmore College, Saratoga Springs, NY 12866, USA.
| |
Collapse
|
47
|
Williams JH. The evolution of pollen germination timing in flowering plants: Austrobaileya scandens (Austrobaileyaceae). AOB PLANTS 2012; 2012:pls010. [PMID: 22567221 PMCID: PMC3345124 DOI: 10.1093/aobpla/pls010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 03/28/2012] [Indexed: 05/07/2023]
Abstract
BACKGROUND AND AIMS The pollination to fertilization process (progamic phase) is thought to have become greatly abbreviated with the origin of flowering plants. In order to understand what developmental mechanisms enabled the speeding of fertilization, comparative data are needed from across the group, especially from early-divergent lineages. I studied the pollen germination process of Austrobaileya scandens, a perennial vine endemic to the Wet Tropics area of northeastern Queensland, Australia, and a member of the ancient angiosperm lineage, Austrobaileyales. METHODOLOGY I used in vivo and in vitro hand pollinations and timed collections to study development from late pollen maturation to just after germination. Then I compared the contribution of pollen germination timing to progamic phase duration in 131 angiosperm species (65 families). PRINCIPAL FINDINGS Mature pollen of Austrobaileya was bicellular, starchless and moderately dehydrated-water content was 31.5 % by weight and volume increased by 57.9 % upon hydration. A callose layer in the inner intine appeared only after pollination. In vivo pollen germination followed a logarithmic curve, rising from 28 % at 1 hour after pollination (hap) to 97 % at 12 hap (R(2) = 0.98). Sufficient pollen germination to fertilize all ovules was predicted to have occurred within 62 min. Across angiosperms, pollen germination ranged from 1 min to >60 h long and required 8.3 ± 9.8 % of the total duration of the progamic phase. SIGNIFICANCE Pollen of Austrobaileya has many plesiomorphic features that are thought to prolong germination. Yet its germination is quite fast for species with desiccation-tolerant pollen (range: <1 to 60 h). Austrobaileya and other early-divergent angiosperms have relatively rapid pollen germination and short progamic phases, comparable to those of many insect-pollinated monocots and eudicots. These results suggest that both the pollen germination and pollen tube growth periods were marked by acceleration of developmental processes early in angiosperm history.
Collapse
|