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Sharma I, Malathi P, Srinivasan R, Bhat SR, Sreenivasulu Y. Embryo sac cellularization defects lead to supernumerary egg cells and twin embryos in Arabidopsis thaliana. iScience 2024; 27:109890. [PMID: 38827396 PMCID: PMC11141147 DOI: 10.1016/j.isci.2024.109890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 03/26/2024] [Accepted: 04/30/2024] [Indexed: 06/04/2024] Open
Abstract
Arabidopsis lines with loss-of-function mutation in Embryo sac-specific Pectin MethylEsterase Inhibitor (Atepmei) gene showed seed sterility with embryo sac cellularization defects. Examination of tissue-cleared mature ovules revealed irregularly positioned nuclei/embryos within the embryo sacs. Egg cell-specific marker (DD45) expression analysis confirmed the presence of multiple egg cells in the mutant embryo sacs. These supernumerary egg cells were functional as evident from the production of twin embryos when supernumerary sperm cells were provided. The results of ruthenium red and tannic acid-ferric chloride staining of developing Atepmei mutant ovules showed that cell wall formation and maintenance were altered around embryo sac nuclei, which also coincided with change in the gamete specification. This report implicates the role of cell walls in gamete cell fate determination by altering cell-cell communication. Our analysis of the twin-embryo phenotype of epmei mutants also sheds light on the boundary conditions for double fertilization in plant reproduction.
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Affiliation(s)
- Isha Sharma
- CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, Himachal Pradesh, India
| | - Pinninti Malathi
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, Telangana, India
| | | | | | - Yelam Sreenivasulu
- CSIR-Institute of Himalayan Bioresource Technology, Palampur 176061, Himachal Pradesh, India
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500007, Telangana, India
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Chettoor AM, Yang B, Evans MMS. Control of cellularization, nuclear localization, and antipodal cell cluster development in maize embryo sacs. Genetics 2023; 225:iyad101. [PMID: 37232380 DOI: 10.1093/genetics/iyad101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 03/30/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023] Open
Abstract
The maize female gametophyte contains four cell types: two synergids, an egg cell, a central cell, and a variable number of antipodal cells. In maize, these cells are produced after three rounds of free-nuclear divisions followed by cellularization, differentiation, and proliferation of the antipodal cells. Cellularization of the eight-nucleate syncytium produces seven cells with two polar nuclei in the central cell. Nuclear localization is tightly controlled in the embryo sac. This leads to precise allocation of the nuclei into the cells upon cellularization. Nuclear positioning within the syncytium is highly correlated with their identity after cellularization. Two mutants are described with extra polar nuclei, abnormal antipodal cell morphology, and reduced antipodal cell number, as well as frequent loss of antipodal cell marker expression. Mutations in one of these genes, indeterminate gametophyte2 encoding a MICROTUBULE ASSOCIATED PROTEIN65-3 homolog, shows a requirement for MAP65-3 in cellularization of the syncytial embryo sac as well as for normal seed development. The timing of the effects of ig2 suggests that the identity of the nuclei in the syncytial female gametophyte can be changed very late before cellularization.
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Affiliation(s)
- Antony M Chettoor
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Bing Yang
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Division of Plant Science and Technology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Matthew M S Evans
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
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Tan C, Liang M, Luo Q, Zhang T, Wang W, Li S, Men S. AUX1, PIN3, and TAA1 collectively maintain fertility in Arabidopsis. PLANTA 2023; 258:68. [PMID: 37598130 DOI: 10.1007/s00425-023-04219-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/27/2023] [Indexed: 08/21/2023]
Abstract
MAIN CONCLUSION We found that auxin synthesis gene TAA1 and auxin polar transport genes AUX1 and PIN3 collectively maintain fertility and seed size in Arabidopsis. Auxin plays a vital role in plant gametophyte development and embryogenesis. The auxin synthesis gene TAA1 and the auxin polar transport genes AUX1 and PIN3 are expressed during Arabidopsis gametophyte and seed development. However, aux1, pin3, and taa1 single mutants only exhibit mild reproductive defects. We, therefore, generated aux1-T pin3 taa1-k2 and aux1-T pin3-2 taa1-k1 triple mutants by crossing or CRISPR/Cas9 technique. These triple mutants displayed severe reproductive defects with approximately 70% and 77%, respectively, of the siliques failing to elongate after anthesis. Reciprocal crosses and microscopy analyses showed that the development of pollen and ovules in the aux1 pin3 taa1 mutants was normal, whereas the filaments were remarkably short, which might be the cause of the silique sterility. Further analyses indicated that the development and morphology of aux1 pin3 taa1 seeds were normal, but their size was smaller compared with that of the wild type. These results indicate that AUX1, PIN3, and TAA1 act in concert to maintain fertility and seed size in Arabidopsis.
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Affiliation(s)
- Chao Tan
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Mengxiao Liang
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Qiong Luo
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Tan Zhang
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Wenhui Wang
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Suxin Li
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Shuzhen Men
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
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Ouedraogo I, Lartaud M, Baroux C, Mosca G, Delgado L, Leblanc O, Verdeil JL, Conéjéro G, Autran D. 3D cellular morphometrics of ovule primordium development in Zea mays reveal differential division and growth dynamics specifying megaspore mother cell singleness. FRONTIERS IN PLANT SCIENCE 2023; 14:1174171. [PMID: 37251753 PMCID: PMC10213557 DOI: 10.3389/fpls.2023.1174171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 04/07/2023] [Indexed: 05/31/2023]
Abstract
Introduction Differentiation of spore mother cells marks the somatic-to-reproductive transition in higher plants. Spore mother cells are critical for fitness because they differentiate into gametes, leading to fertilization and seed formation. The female spore mother cell is called the megaspore mother cell (MMC) and is specified in the ovule primordium. The number of MMCs varies by species and genetic background, but in most cases, only a single mature MMC enters meiosis to form the embryo sac. Multiple candidate MMC precursor cells have been identified in both rice and Arabidopsis, so variability in MMC number is likely due to conserved early morphogenetic events. In Arabidopsis, the restriction of a single MMC per ovule, or MMC singleness, is determined by ovule geometry. To look for potential conservation of MMC ontogeny and specification mechanisms, we undertook a morphogenetic description of ovule primordium growth at cellular resolution in the model crop maize. Methods We generated a collection of 48 three-dimensional (3D) ovule primordium images for five developmental stages, annotated for 11 cell types. Quantitative analysis of ovule and cell morphological descriptors allowed the reconstruction of a plausible developmental trajectory of the MMC and its neighbors. Results The MMC is specified within a niche of enlarged, homogenous L2 cells, forming a pool of candidate archesporial (MMC progenitor) cells. A prevalent periclinal division of the uppermost central archesporial cell formed the apical MMC and the underlying cell, a presumptive stack cell. The MMC stopped dividing and expanded, acquiring an anisotropic, trapezoidal shape. By contrast, periclinal divisions continued in L2 neighbor cells, resulting in a single central MMC. Discussion We propose a model where anisotropic ovule growth in maize drives L2 divisions and MMC elongation, coupling ovule geometry with MMC fate.
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Affiliation(s)
- Inès Ouedraogo
- DIADE, University of Montpellier, IRD, CIRAD, Montpellier, France
| | - Marc Lartaud
- AGAP, University of Montpellier, CIRAD, INRAE, Institut SupAgro, Montpellier, France
| | - Célia Baroux
- Institute of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | - Gabriella Mosca
- Institute of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zürich, Zürich, Switzerland
| | | | - Oliver Leblanc
- DIADE, University of Montpellier, IRD, CIRAD, Montpellier, France
| | - Jean-Luc Verdeil
- AGAP, University of Montpellier, CIRAD, INRAE, Institut SupAgro, Montpellier, France
| | - Geneviève Conéjéro
- IPSIM, University of Montpellier, CNRS, INRAE, Institut SupAgro, Montpellier, France
| | - Daphné Autran
- DIADE, University of Montpellier, IRD, CIRAD, Montpellier, France
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Liu H, Luo Q, Tan C, Song J, Zhang T, Men S. Biosynthesis- and transport-mediated dynamic auxin distribution during seed development controls seed size in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:1259-1277. [PMID: 36648165 DOI: 10.1111/tpj.16109] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/23/2022] [Accepted: 01/11/2023] [Indexed: 06/17/2023]
Abstract
Auxin is indispensable to the fertilization-induced coordinated development of the embryo, endosperm, and seed coat. However, little attention has been given to the distribution pattern, maintenance mechanism, and function of auxin throughout the process of seed development. In the present study, we found that auxin response signals display a dynamic distribution pattern during Arabidopsis seed development. Shortly after fertilization, strong auxin response signals were observed at the funiculus, chalaza, and micropylar integument where the embryo attaches. Later, additional signals appeared at the middle layer of the inner integument (ii1') above the chalaza and the whole inner layer of the outer integument (oi1). These signals peaked when the seed was mature, then declined upon desiccation and disappeared in the dried seed. Auxin biosynthesis genes, including ASB1, TAA1, YUC1, YUC4, YUC8, and YUC9, contributed to the accumulation of auxin in the funiculus and seed coat. Auxin efflux carrier PIN3 and influx carrier AUX1 also contributed to the polar auxin distribution in the seed coat. PIN3 was expressed in the ii1 (innermost layer of the inner integument) and oi1 layers of the integument and showed polar localization. AUX1 was expressed in both layers of the outer integument and the endosperm and displayed a uniform localization. Further research demonstrated that the accumulation of auxin in the seed coat regulates seed size. Transgenic plants that specifically express the YUC8 gene in the oi2 or ii1 seed coat produced larger seeds. These results provide useful tools for cultivating high-yielding crops.
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Affiliation(s)
- Huabin Liu
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Qiong Luo
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Chao Tan
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Jia Song
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Tan Zhang
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Shuzhen Men
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin, 300071, China
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Chen JJ, Wang W, Qin WQ, Men SZ, Li HL, Mitsuda N, Ohme-Takagi M, Wu AM. Transcription factors KNAT3 and KNAT4 are essential for integument and ovule formation in Arabidopsis. PLANT PHYSIOLOGY 2023; 191:463-478. [PMID: 36342216 PMCID: PMC9806662 DOI: 10.1093/plphys/kiac513] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Integuments form important protective cell layers surrounding the developing ovules in gymno- and angiosperms. Although several genes have been shown to influence the development of integuments, the transcriptional regulatory mechanism is still poorly understood. In this work, we report that the Class II KNOTTED1-LIKE HOMEOBOX (KNOX II) transcription factors KNOTTED1-LIKE HOMEBOX GENE 3 (KNAT3) and KNAT4 regulate integument development in Arabidopsis (Arabidopsis thaliana). KNAT3 and KNAT4 were co-expressed in inflorescences and especially in young developing ovules. The loss-of-function double mutant knat3 knat4 showed an infertility phenotype, in which both inner and outer integuments of the ovule are arrested at an early stage and form an amorphous structure as in the bell1 (bel1) mutant. The expression of chimeric KNAT3- and KNAT4-EAR motif repression domain (SRDX repressors) resulted in severe seed abortion. Protein-protein interaction assays demonstrated that KNAT3 and KNAT4 interact with each other and also with INNER NO OUTER (INO), a key transcription factor required for the outer integument formation. Transcriptome analysis showed that the expression of genes related with integument development is influenced in the knat3 knat4 mutant. The knat3 knat4 mutant also had a lower indole-3-acetic acid (IAA) content, and some auxin signaling pathway genes were downregulated. Moreover, transactivation analysis indicated that KNAT3/4 and INO activate the auxin signaling gene IAA INDUCIBLE 14 (IAA14). Taken together, our study identified KNAT3 and KNAT4 as key factors in integument development in Arabidopsis.
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Affiliation(s)
- Jia-Jun Chen
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Wei Wang
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå 90183, Sweden
| | - Wen-Qi Qin
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Shu-Zhen Men
- Tianjin Key Laboratory of Protein Sciences, Department of Plant Biology and Ecology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Hui-Ling Li
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
| | - Nobutaka Mitsuda
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Masaru Ohme-Takagi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Ai-Min Wu
- The State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou 510642, China
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architectures, South China Agricultural University, Guangzhou 510642, China
- Guangdong Laboratory of Lingnan Modern Agriculture, Guangzhou 510642, China
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Zhang J, Pai Q, Yue L, Wu X, Liu H, Wang W. Cytokinin regulates female gametophyte development by cell cycle modulation in Arabidopsis thaliana. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 324:111419. [PMID: 35995110 DOI: 10.1016/j.plantsci.2022.111419] [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: 05/17/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Male and female gametophyte development, double fertilization, and embryogenesis are key to alternating generations in angiosperms. The female gametophyte of Arabidopsis is an eight-nucleate haploid structure developed from functional megaspores (FMs) through three flawless mitoses regulated by a series of cell cycle genes. Cytokinin, an important phytohormone, plays a critical role in the regulation of plant growth and development. However, the mechanisms by which cytokinins regulate female gametophyte development remain largely unknown. In this study, we constructed transgenic plants (pES1::CKX1) with low cytokinin levels in the embryo sac. Phenotypic analysis showed that pES1::CKX1 inhibits female gametophyte development. Microscopic observation revealed that female gametophyte development of pES1::CKX1 was delayed. The promoters of all cell cycle genes were cloned and transformed into wild-type (WT). We crossed these transgenic plants of cell cycle genes expressed in ovules with pES1::CKX1 and compared the expression level of β-glucuronidase (GUS) in pES1::CKX1 and WT. Many cell cycle-regulated genes were up or downregulated in pES1::CKX1 compared with WT, and the embryo sac development cell cycle in cycd2;1/+ cycd3;3 was defective. Our results demonstrated that cytokinin affects cell division in the female gametophyte by affecting the expression of cell cycle genes.
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Affiliation(s)
- Jinghua Zhang
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Qiaofeng Pai
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Ling Yue
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Xiaolin Wu
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China
| | - Hui Liu
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China.
| | - Wei Wang
- National Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China.
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Li W, Li M, Li S, Zhang Y, Li X, Xu G, Yu L. Function of Rice High-Affinity Potassium Transporters in Pollen Development and Fertility. PLANT & CELL PHYSIOLOGY 2022; 63:967-980. [PMID: 35536598 DOI: 10.1093/pcp/pcac061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/12/2022] [Accepted: 05/04/2022] [Indexed: 06/14/2023]
Abstract
Plant High-affinity K+ transporters/K+ uptake permeases/K+ transporters (HAK/KUP/KT) transporters have been predicted as membrane H+-K+ symporters in facilitating K+ uptake and distribution, while their role in seed production remains to be elucidated. In this study, we report that OsHAK26 is preferentially expressed in anthers and seed husks and located in the Golgi apparatus. Knockout of either OsHAK26 or plasma membrane located H+-K+ symporter gene OsHAK1 or OsHAK5 in both Nipponbare and Dongjin cultivars caused distorted anthers, reduced number and germination rate of pollen grains. Seed-setting rate assay by reciprocal cross-pollination between the mutants of oshak26, oshak1, oshak5 and their wild types confirmed that each HAK transporter is foremost for pollen viability, seed-setting and grain yield. Intriguingly, the pollens of oshak26 showed much thinner wall and were more vulnerable to desiccation than those of oshak1 or oshak5. In vitro assay revealed that the pollen germination rate of oshak5 was dramatically affected by external K+ concentration. The results suggest that the role of OsHAK26 in maintaining pollen development and fertility may relate to its proper cargo sorting for construction of pollen walls, while the role of OsHAK1 and OsHAK5 in maintaining seed production likely relates to their transcellular K+ transport activity.
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Affiliation(s)
- Weihong Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
- China MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
- Jiangsu Academy of Agricultural Sciences, Huaiyin Institute of Agricultural Sciences of Xuhuai Region in Jiangsu, Huaian, Jiangsu 223001, China
| | - Mengqi Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Shen Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanfan Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Xin Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Guohua Xu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
- China MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Ling Yu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China
- China MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, College of Resources and Environmental Science, Nanjing Agricultural University, Nanjing 210095, China
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Siena LA, Azzaro CA, Podio M, Stein J, Leblanc O, Pessino SC, Ortiz JPA. The Auxin-Response Repressor IAA30 Is Down-Regulated in Reproductive Tissues of Apomictic Paspalum notatum. PLANTS 2022; 11:plants11111472. [PMID: 35684245 PMCID: PMC9182604 DOI: 10.3390/plants11111472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 04/20/2022] [Accepted: 05/18/2022] [Indexed: 11/25/2022]
Abstract
The capacity for apomixis in Paspalum notatum is controlled by a single-dominant genomic region, which shows strong synteny to a portion of rice chromosome 12 long arm. The locus LOC_Os12g40890, encoding the Auxin/Indole-3-Acetic Acid (Aux/IAA) family member OsIAA30, is located in this rice genomic segment. The objectives of this work were to identify transcripts coding for Aux/IAA proteins expressed in reproductive tissues of P. notatum, detect the OsIAA30 putative ortholog and analyze its temporal and spatial expression pattern in reproductive organs of sexual and apomictic plants. Thirty-three transcripts coding for AUX/IAA proteins were identified. Predicted protein alignment and phylogenetic analysis detected a highly similar sequence to OsIAA30 (named as PnIAA30) present in both sexual and apomictic samples. The expression assays of PnIAA30 showed a significant down-regulation in apomictic spikelets compared to sexual ones at the stages of anthesis and post-anthesis, representation levels negatively correlated with apospory expressivity and different localizations in sexual and apomictic ovules. Several PnIAA30 predicted interactors also appeared differentially regulated in the sexual and apomictic floral transcriptomes. Our results showed that an auxin-response repressor similar to OsIAA30 is down-regulated in apomictic spikelets of P. notatum and suggests a contrasting regulation of auxin signaling during sexual and asexual seed formation.
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Affiliation(s)
- Lorena Adelina Siena
- Laboratorio de Biología Molecular, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR) CONICET-UNR, Facultad de Ciencias Agrarias, Campo Experimental Villarino, Universidad Nacional de Rosario, Zavalla S2125ZAA, Santa Fe, Argentina; (L.A.S.); (C.A.A.); (M.P.); (J.S.); (S.C.P.)
| | - Celeste Antonela Azzaro
- Laboratorio de Biología Molecular, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR) CONICET-UNR, Facultad de Ciencias Agrarias, Campo Experimental Villarino, Universidad Nacional de Rosario, Zavalla S2125ZAA, Santa Fe, Argentina; (L.A.S.); (C.A.A.); (M.P.); (J.S.); (S.C.P.)
| | - Maricel Podio
- Laboratorio de Biología Molecular, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR) CONICET-UNR, Facultad de Ciencias Agrarias, Campo Experimental Villarino, Universidad Nacional de Rosario, Zavalla S2125ZAA, Santa Fe, Argentina; (L.A.S.); (C.A.A.); (M.P.); (J.S.); (S.C.P.)
| | - Juliana Stein
- Laboratorio de Biología Molecular, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR) CONICET-UNR, Facultad de Ciencias Agrarias, Campo Experimental Villarino, Universidad Nacional de Rosario, Zavalla S2125ZAA, Santa Fe, Argentina; (L.A.S.); (C.A.A.); (M.P.); (J.S.); (S.C.P.)
| | - Olivier Leblanc
- DIADE, Université de Montpellier, IRD, CIRAD, 34394 Montpellier, France;
| | - Silvina Claudia Pessino
- Laboratorio de Biología Molecular, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR) CONICET-UNR, Facultad de Ciencias Agrarias, Campo Experimental Villarino, Universidad Nacional de Rosario, Zavalla S2125ZAA, Santa Fe, Argentina; (L.A.S.); (C.A.A.); (M.P.); (J.S.); (S.C.P.)
| | - Juan Pablo Amelio Ortiz
- Laboratorio de Biología Molecular, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR) CONICET-UNR, Facultad de Ciencias Agrarias, Campo Experimental Villarino, Universidad Nacional de Rosario, Zavalla S2125ZAA, Santa Fe, Argentina; (L.A.S.); (C.A.A.); (M.P.); (J.S.); (S.C.P.)
- Correspondence: ; Tel.: +54-341-4970080/85 (ext. 1180)
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10
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Plant egg cell fate determination depends on its exact position in female gametophyte. Proc Natl Acad Sci U S A 2021; 118:2017488118. [PMID: 33597298 DOI: 10.1073/pnas.2017488118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Plant fertilization involves both an egg cell, which fuses with a sperm cell, and synergid cells, which guide pollen tubes for sperm cell delivery. Therefore, egg and synergid cell functional specifications are prerequisites for successful fertilization. However, how the egg and synergid cells, referred to as the "egg apparatus," derived from one mother cell develop into distinct cell types remains an unanswered question. In this report, we show that the final position of the nuclei in female gametophyte determines the cell fate of the egg apparatus. We established a live imaging system to visualize the dynamics of nuclear positioning and cell identity establishment in the female gametophyte. We observed that free nuclei should migrate to a specific position before egg apparatus specialization. Artificial changing in the nuclear position on disturbance of the actin cytoskeleton, either in vitro or in vivo, could reset the cell fate of the egg apparatus. We also found that nuclei of the same origin moved to different positions and then showed different cell identities, whereas nuclei of different origins moved to the same position showed the same cell identity, indicating that the final positions of the nuclei, rather than specific nucleus lineage, play critical roles in the egg apparatus specification. Furthermore, the active auxin level was higher in the egg cell than in synergid cells. Auxin transport inhibitor could decrease the auxin level in egg cells and impair egg cell identity, suggesting that directional and accurate auxin distribution likely acts as a positional cue for egg apparatus specialization.
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11
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The Rab Geranylgeranyl Transferase Beta Subunit Is Essential for Embryo and Seed Development in Arabidopsis thaliana. Int J Mol Sci 2021; 22:ijms22157907. [PMID: 34360673 PMCID: PMC8347404 DOI: 10.3390/ijms22157907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 12/18/2022] Open
Abstract
Auxin is a key regulator of plant development affecting the formation and maturation of reproductive structures. The apoplastic route of auxin transport engages influx and efflux facilitators from the PIN, AUX and ABCB families. The polar localization of these proteins and constant recycling from the plasma membrane to endosomes is dependent on Rab-mediated vesicular traffic. Rab proteins are anchored to membranes via posttranslational addition of two geranylgeranyl moieties by the Rab Geranylgeranyl Transferase enzyme (RGT), which consists of RGTA, RGTB and REP subunits. Here, we present data showing that seed development in the rgtb1 mutant, with decreased vesicular transport capacity, is disturbed. Both pre- and post-fertilization events are affected, leading to a decrease in seed yield. Pollen tube recognition at the stigma and its guidance to the micropyle is compromised and the seed coat forms incorrectly. Excess auxin in the sporophytic tissues of the ovule in the rgtb1 plants leads to an increased tendency of autonomous endosperm formation in unfertilized ovules and influences embryo development in a maternal sporophytic manner. The results show the importance of vesicular traffic for sexual reproduction in flowering plants, and highlight RGTB1 as a key component of sporophytic-filial signaling.
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12
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Cai H, Liu L, Zhang M, Chai M, Huang Y, Chen F, Yan M, Su Z, Henderson I, Palanivelu R, Chen X, Qin Y. Spatiotemporal control of miR398 biogenesis, via chromatin remodeling and kinase signaling, ensures proper ovule development. THE PLANT CELL 2021; 33:1530-1553. [PMID: 33570655 PMCID: PMC8254498 DOI: 10.1093/plcell/koab056] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/02/2021] [Indexed: 05/11/2023]
Abstract
The coordinated development of sporophytic and gametophytic tissues is essential for proper ovule patterning and fertility. However, the mechanisms regulating their integrated development remain poorly understood. Here, we report that the Swi2/Snf2-Related1 (SWR1) chromatin-remodeling complex acts with the ERECTA receptor kinase-signaling pathway to control female gametophyte and integument growth in Arabidopsis thaliana by inhibiting transcription of the microRNA gene MIR398c in early-stage megagametogenesis. Moreover, pri-miR398c is transcribed in the female gametophyte but is then translocated to and processed in the ovule sporophytic tissues. Together, SWR1 and ERECTA also activate ARGONAUTE10 (AGO10) expression in the chalaza; AGO10 sequesters miR398, thereby ensuring the expression of three AGAMOUS-LIKE (AGL) genes (AGL51, AGL52, and AGL78) in the female gametophyte. In the context of sexual organ morphogenesis, these findings suggest that the spatiotemporal control of miRNA biogenesis, resulting from coordination between chromatin remodeling and cell signaling, is essential for proper ovule development in Arabidopsis.
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Affiliation(s)
- Hanyang Cai
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Liping Liu
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Man Zhang
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Mengnan Chai
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Youmei Huang
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Fangqian Chen
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Maokai Yan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, China
| | - Zhenxia Su
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ian Henderson
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom
| | | | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, United States
| | - Yuan Qin
- College of Life Science, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi Key Lab of Sugarcane Biology, College of Agriculture, Guangxi University, Nanning 530004, China
- Author for correspondence:
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Wang J, Guo X, Xiao Q, Zhu J, Cheung AY, Yuan L, Vierling E, Xu S. Auxin efflux controls orderly nucellar degeneration and expansion of the female gametophyte in Arabidopsis. THE NEW PHYTOLOGIST 2021; 230:2261-2274. [PMID: 33338267 PMCID: PMC8248126 DOI: 10.1111/nph.17152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 12/12/2020] [Indexed: 05/11/2023]
Abstract
The nucellus tissue in flowering plants provides nutrition for the development of the female gametophyte (FG) and young embryo. The nucellus degenerates as the FG develops, but the mechanism controlling the coupled process of nucellar degeneration and FG expansion remains largely unknown. The degeneration process of the nucellus and spatiotemporal auxin distribution in the developing ovule before fertilization were investigated in Arabidopsis thaliana. Nucellar degeneration before fertilization occurs through vacuolar cell death and in an ordered degeneration fashion. This sequential nucellar degeneration is controlled by the signalling molecule auxin. Auxin efflux plays the core role in precisely controlling the spatiotemporal pattern of auxin distribution in the nucellus surrounding the FG. The auxin efflux carrier PIN1 transports maternal auxin into the nucellus while PIN3/PIN4/PIN7 further delivers auxin to degenerating nucellar cells and concurrently controls FG central vacuole expansion. Notably, auxin concentration and auxin efflux are controlled by the maternal tissues, acting as a key communication from maternal to filial tissue.
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Affiliation(s)
- Junzhe Wang
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Xiaolong Guo
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Qiang Xiao
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Jianchu Zhu
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
| | - Alice Y. Cheung
- Department of Biochemistry and Molecular BiologyUniversity of MassachusettsAmherstMA01003USA
| | - Li Yuan
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxi712100China
| | - Elizabeth Vierling
- Department of Biochemistry and Molecular BiologyUniversity of MassachusettsAmherstMA01003USA
| | - Shengbao Xu
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of AgronomyNorthwest A&F UniversityYanglingShaanxi712100China
- Department of Biochemistry and Molecular BiologyUniversity of MassachusettsAmherstMA01003USA
- Ministry of Education Key Laboratory of Cell Activities and Stress AdaptationsSchool of Life SciencesLanzhou UniversityLanzhouGansu730000China
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14
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Rojek J, Tucker MR, Pinto SC, Rychłowski M, Lichocka M, Soukupova H, Nowakowska J, Bohdanowicz J, Surmacz G, Gutkowska M. Rab-dependent vesicular traffic affects female gametophyte development in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:320-340. [PMID: 32939545 PMCID: PMC7853608 DOI: 10.1093/jxb/eraa430] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/15/2020] [Indexed: 05/10/2023]
Abstract
Eukaryotic cells rely on the accuracy and efficiency of vesicular traffic. In plants, disturbances in vesicular trafficking are well studied in quickly dividing root meristem cells or polar growing root hairs and pollen tubes. The development of the female gametophyte, a unique haploid reproductive structure located in the ovule, has received far less attention in studies of vesicular transport. Key molecules providing the specificity of vesicle formation and its subsequent recognition and fusion with the acceptor membrane are Rab proteins. Rabs are anchored to membranes by covalently linked geranylgeranyl group(s) that are added by the Rab geranylgeranyl transferase (RGT) enzyme. Here we show that Arabidopsis plants carrying mutations in the gene encoding the β-subunit of RGT (rgtb1) exhibit severely disrupted female gametogenesis and this effect is of sporophytic origin. Mutations in rgtb1 lead to internalization of the PIN1 and PIN3 proteins from the basal membranes to vesicles in provascular cells of the funiculus. Decreased transport of auxin out of the ovule is accompanied by auxin accumulation in tissue surrounding the growing gametophyte. In addition, female gametophyte development arrests at the uni- or binuclear stage in a significant portion of the rgtb1 ovules. These observations suggest that communication between the sporophyte and the developing female gametophyte relies on Rab-dependent vesicular traffic of the PIN1 and PIN3 transporters and auxin efflux out of the ovule.
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Affiliation(s)
- Joanna Rojek
- Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk, Poland
| | - Matthew R Tucker
- Waite Research Institute, School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, South Australia, Australia
| | - Sara C Pinto
- Waite Research Institute, School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, South Australia, Australia
- LAQV REQUIMTE, Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, rua do Campo Alegre s/n Porto, Portugal
| | - Michał Rychłowski
- Intercollegiate Faculty of Biotechnology, University of Gdansk, Abrahama 58, Gdansk, Poland
| | - Małgorzata Lichocka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, Warsaw, Poland
| | - Hana Soukupova
- Institute of Experimental Botany, Czech Academy of Sciences, Rozvojova 263, Praha 6 Lysolaje, Czech Republic
| | - Julita Nowakowska
- Faculty of Biology, University of Warsaw, Miecznikowa 1, Warsaw, Poland
| | - Jerzy Bohdanowicz
- Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk, Poland
| | - Gabriela Surmacz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, Warsaw, Poland
| | - Małgorzata Gutkowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, Warsaw, Poland
- Correspondence:
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15
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Cucinotta M, Cavalleri A, Chandler JW, Colombo L. Auxin and Flower Development: A Blossoming Field. Cold Spring Harb Perspect Biol 2021; 13:a039974. [PMID: 33355218 PMCID: PMC7849340 DOI: 10.1101/cshperspect.a039974] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The establishment of the species-specific floral organ body plan involves many coordinated spatiotemporal processes, which include the perception of positional information that specifies floral meristem and floral organ founder cells, coordinated organ outgrowth coupled with the generation and maintenance of inter-organ and inter-whorl boundaries, and the termination of meristem activity. Auxin is integrated within the gene regulatory networks that control these processes and plays instructive roles at the level of tissue-specific biosynthesis and polar transport to generate local maxima, perception, and signaling. Key features of auxin function in several floral contexts include cell nonautonomy, interaction with cytokinin gradients, and the central role of MONOPTEROS and ETTIN to regulate canonical and noncanonical auxin response pathways, respectively. Arabidopsis flowers are not representative of the enormous angiosperm floral diversity; therefore, comparative studies are required to understand how auxin underlies these developmental differences. It will be of great interest to compare the conservation of auxin pathways among flowering plants and to discuss the evolutionary role of auxin in floral development.
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Affiliation(s)
- Mara Cucinotta
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, Italy
| | - Alex Cavalleri
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, Italy
| | | | - Lucia Colombo
- Dipartimento di Bioscienze, Università degli Studi di Milano, 20133 Milan, Italy
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16
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Li HJ, Yang WC. Central Cell in Flowering Plants: Specification, Signaling, and Evolution. FRONTIERS IN PLANT SCIENCE 2020; 11:590307. [PMID: 33193544 PMCID: PMC7609669 DOI: 10.3389/fpls.2020.590307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 09/28/2020] [Indexed: 05/05/2023]
Abstract
During the reproduction of animals and lower plants, one sperm cell usually outcompetes the rivals to fertilize a single egg cell. But in flowering plants, two sperm cells fertilize the two adjacent dimorphic female gametes, the egg and central cell, respectively, to initiate the embryo and endosperm within a seed. The endosperm nourishes the embryo development and is also the major source of nutrition in cereals for humankind. Central cell as one of the key innovations of flowering plants is the biggest cell in the multicellular haploid female gametophyte (embryo sac). The embryo sac differentiates from the meiotic products through successive events of nuclear divisions, cellularization, and cell specification. Nowadays, accumulating lines of evidence are raveling multiple roles of the central cell rather than only the endosperm precursor. In this review, we summarize the current understanding on its cell fate specification, intercellular communication, and evolution. We also highlight some key unsolved questions for the further studies in this field.
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Affiliation(s)
- Hong-Ju Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
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17
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Hater F, Nakel T, Groß-Hardt R. Reproductive Multitasking: The Female Gametophyte. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:517-546. [PMID: 32442389 DOI: 10.1146/annurev-arplant-081519-035943] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fertilization of flowering plants requires the organization of complex tasks, many of which become integrated by the female gametophyte (FG). The FG is a few-celled haploid structure that orchestrates division of labor to coordinate successful interaction with the sperm cells and their transport vehicle, the pollen tube. As reproductive outcome is directly coupled to evolutionary success, the underlying mechanisms are under robust molecular control, including integrity check and repair mechanisms. Here, we review progress on understanding the development and function of the FG, starting with the functional megaspore, which represents the haploid founder cell of the FG. We highlight recent achievements that have greatly advanced our understanding of pollen tube attraction strategies and the mechanisms that regulate plant hybridization and gamete fusion. In addition, we discuss novel insights into plant polyploidization strategies that expand current concepts on the evolution of flowering plants.
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Affiliation(s)
- Friederike Hater
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
| | - Thomas Nakel
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
| | - Rita Groß-Hardt
- Centre for Biomolecular Interactions, University of Bremen, 28359 Bremen, Germany;
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18
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Prigge MJ, Platre M, Kadakia N, Zhang Y, Greenham K, Szutu W, Pandey BK, Bhosale RA, Bennett MJ, Busch W, Estelle M. Genetic analysis of the Arabidopsis TIR1/AFB auxin receptors reveals both overlapping and specialized functions. eLife 2020; 9:54740. [PMID: 32067636 PMCID: PMC7048394 DOI: 10.7554/elife.54740] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 02/04/2020] [Indexed: 01/03/2023] Open
Abstract
The TIR1/AFB auxin co-receptors mediate diverse responses to the plant hormone auxin. The Arabidopsis genome encodes six TIR1/AFB proteins representing three of the four clades that were established prior to angiosperm radiation. To determine the role of these proteins in plant development we performed an extensive genetic analysis involving the generation and characterization of all possible multiply-mutant lines. We find that loss of all six TIR1/AFB proteins results in early embryo defects and eventually seed abortion, and yet a single wild-type allele of TIR1 or AFB2 is sufficient to support growth throughout development. Our analysis reveals extensive functional overlap between even the most distantly related TIR1/AFB genes except for AFB1. Surprisingly, AFB1 has a specialized function in rapid auxin-dependent inhibition of root growth and early phase of root gravitropism. This activity may be related to a difference in subcellular localization compared to the other members of the family.
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Affiliation(s)
- Michael J Prigge
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, United States
| | - Matthieu Platre
- Plant Molecular and Cellular Biology Laboratory and Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, United States
| | - Nikita Kadakia
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, United States
| | - Yi Zhang
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, United States
| | - Kathleen Greenham
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, United States
| | - Whitnie Szutu
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, United States
| | - Bipin Kumar Pandey
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, United Kingdom
| | - Rahul Arvind Bhosale
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, United Kingdom
| | - Malcolm J Bennett
- Plant and Crop Sciences, School of Biosciences, University of Nottingham, Nottingham, United Kingdom
| | - Wolfgang Busch
- Plant Molecular and Cellular Biology Laboratory and Integrative Biology Laboratory, Salk Institute for Biological Studies, La Jolla, United States
| | - Mark Estelle
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, United States
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Abstract
The plant haploid generation is specified late in higher plant development, and post-meiotic haploid plant cells divide mitotically to produce a haploid gametophyte, in which a subset of cells differentiates into the gametes. The immediate mother of the angiosperm seed is the female gametophyte, also called the embryo sac. In most flowering plants the embryo sac is comprised of two kinds of gametes (egg and central cell) and two kinds of subsidiary cells (antipodals and synergids) all of which descend from a single haploid spore produced by meiosis. The embryo sac develops within a specialized organ of the flower called the ovule, which supports and controls many steps in the development of both the embryo sac and the seed. Double fertilization of the central cell and egg cell by the two sperm cells of a pollen grain produce the endosperm and embryo of the seed, respectively. The endosperm and embryo develop under the influence of their precursor gametes and the surrounding tissues of the ovule and the gametophyte. The final size and pattern of the angiosperm seed then is the result of complex interactions across multiple tissues of three different generations (maternal sporophyte, maternal gametophyte, and the fertilization products) and three different ploidies (haploid gametophyte, diploid parental sporophyte and embryo, and triploid endosperm).
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20
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Zühl L, Volkert C, Ibberson D, Schmidt A. Differential activity of F-box genes and E3 ligases distinguishes sexual versus apomictic germline specification in Boechera. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5643-5657. [PMID: 31294816 PMCID: PMC6812705 DOI: 10.1093/jxb/erz323] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 07/01/2019] [Indexed: 05/22/2023]
Abstract
Germline specification is the first step during sexual and apomictic plant reproduction, and takes place in the nucellus of the ovule, a specialized domain of the reproductive flower tissues. In each case, a sporophytic cell is determined to form the sexual megaspore mother cell (MMC) or an apomictic initial cell (AIC). These differ in their developmental fates: while the MMC undergoes meiosis, the AIC modifies or omits meiosis to form the female gametophyte. Despite great interest in these distinct developmental processes, little is known about their gene regulatory basis. To elucidate the gene regulatory networks underlying germline specification, we conducted tissue-specific transcriptional profiling using laser-assisted microdissection and RNA sequencing to compare the transcriptomes of nucellar tissues between different sexual and apomictic Boechera accessions representing four species and two ploidy levels. This allowed us to distinguish between expression differences caused by genetic background or reproductive mode. Statistical data analysis revealed 45 genes that were significantly differentially expressed, and which potentially play a role for determination of the reproductive mode. Based on annotations, these included F-box genes and E3 ligases that most likely relate to genes previously described as regulators important for germline development. Our findings provide novel insights into the transcriptional basis of sexual and apomictic reproduction.
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Affiliation(s)
- Luise Zühl
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
- Present address: Max Planck Institute for Plant Breeding Research, Department of Comparative Development and Genetics, Carl-von-Linné-Weg 10, D-50829 Cologne
| | - Christopher Volkert
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Im Neuenheimer Feld, Heidelberg
| | - Anja Schmidt
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
- Correspondence:
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21
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Lora J, Yang X, Tucker MR. Establishing a framework for female germline initiation in the plant ovule. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2937-2949. [PMID: 31063548 DOI: 10.1093/jxb/erz212] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 05/02/2019] [Indexed: 05/21/2023]
Abstract
Female gametogenesis in flowering plants initiates in the ovule, where a single germline progenitor differentiates from a pool of somatic cells. Germline initiation is a fundamental prerequisite for seed development but is poorly understood at the molecular level due to the location of the cells deep within the flower. Studies in Arabidopsis have shown that regulators of germline development include transcription factors such as NOZZLE/SPOROCYTELESS and WUSCHEL, components of the RNA-dependent DNA methylation pathway such as ARGONAUTE9 and RNA-DEPENDENT RNA POLYMERASE 6, and phytohormones such as auxin and cytokinin. These factors accumulate in a range of cell types from where they establish an environment to support germline differentiation. Recent studies provide fresh insight into the transition from somatic to germline identity, linking chromatin regulators, cell cycle genes, and novel mobile signals, capitalizing on cell type-specific methodologies in both dicot and monocot models. These findings are providing unique molecular and compositional insight into the mechanistic basis and evolutionary conservation of female germline development in plants.
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Affiliation(s)
- Jorge Lora
- Department of Subtropical Fruits, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Algarrobo-Costa, Málaga, Spain
| | - Xiujuan Yang
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Mathew R Tucker
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
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22
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Ma C, Li B, Wang L, Xu ML, Lizhu E, Jin H, Wang Z, Ye JR. Characterization of phytohormone and transcriptome reprogramming profiles during maize early kernel development. BMC PLANT BIOLOGY 2019; 19:197. [PMID: 31088353 PMCID: PMC6515667 DOI: 10.1186/s12870-019-1808-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/26/2019] [Indexed: 05/23/2023]
Abstract
BACKGROUND During maize early kernel development, the dramatic transcriptional reprogramming determines the rate of developmental progression, and phytohormone plays critical role in these important processes. To investigate the phytohormone levels and transcriptome reprogramming profiles during maize early kernel development, two maize inbreds with similar genetic background but different mature kernel sizes (ILa and ILb) were used. RESULTS The levels of indole-3-acetic acid (IAA) were increased continuously in maize kernels from 5 days after pollination (DAP) to 10 DAP. ILa had smaller mature kernels than ILb, and ILa kernels had significantly lower IAA levels and significantly higher SA levels than ILb at 10 DAP. The different phytohormone profiles correlated with different transcriptional reprogramming in the two kernels. The global transcriptomes in ILa and ILb kernels were strikingly different at 5 DAP, and their differences peaked at 8 DAP. Functional analysis showed that the biggest transcriptome difference between the two kernels is those response to biotic and abiotic stresses. Further analyses indicated that the start of dramatic transcriptional reprogramming and the onset of significantly enriched functional categories, especially the "plant hormone signal transduction" and "starch and sucrose metabolism", was earlier in ILa than in ILb, whereas more significant enrichment of those functional categories occurred at later stage of kernel development in ILb. CONCLUSIONS These results indicate that later onset of the significantly enriched functional categories, coincide with their stronger activities at a later developmental stage and higher IAA level, are necessary for young kernels to undergo longer mitotic activity and finally develop a larger kernel size. The different onset times and complex interactions of the important functional categories, especially phytohormone signal, and carbohydrate metabolism, form the most important molecular regulators mediating maize early kernel development.
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Affiliation(s)
- Chuanyu Ma
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
| | - Bo Li
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
| | - Lina Wang
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
| | - Ming-liang Xu
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
| | - E. Lizhu
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
| | - Hongyu Jin
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
| | - Zhicheng Wang
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
| | - Jian-rong Ye
- National Maize Improvement Center, China Agricultural University, 2 West Yuanmingyuan Road, Beijing, 100193 People’s Republic of China
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23
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Shirley NJ, Aubert MK, Wilkinson LG, Bird DC, Lora J, Yang X, Tucker MR. Translating auxin responses into ovules, seeds and yield: Insight from Arabidopsis and the cereals. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:310-336. [PMID: 30474296 DOI: 10.1111/jipb.12747] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/16/2018] [Indexed: 05/27/2023]
Abstract
Grain production in cereal crops depends on the stable formation of male and female gametes in the flower. In most angiosperms, the female gamete is produced from a germline located deep within the ovary, protected by several layers of maternal tissue, including the ovary wall, ovule integuments and nucellus. In the field, germline formation and floret fertility are major determinants of yield potential, contributing to traits such as seed number, weight and size. As such, stimuli affecting the timing and duration of reproductive phases, as well as the viability, size and number of cells within reproductive organs can significantly impact yield. One key stimulant is the phytohormone auxin, which influences growth and morphogenesis of female tissues during gynoecium development, gametophyte formation, and endosperm cellularization. In this review we consider the role of the auxin signaling pathway during ovule and seed development, first in the context of Arabidopsis and then in the cereals. We summarize the gene families involved and highlight distinct expression patterns that suggest a range of roles in reproductive cell specification and fate. This is discussed in terms of seed production and how targeted modification of different tissues might facilitate improvements.
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Affiliation(s)
- Neil J Shirley
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Matthew K Aubert
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Laura G Wilkinson
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Dayton C Bird
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Jorge Lora
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Xiujuan Yang
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - Matthew R Tucker
- School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
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24
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Robert HS. Molecular Communication for Coordinated Seed and Fruit Development: What Can We Learn from Auxin and Sugars? Int J Mol Sci 2019; 20:E936. [PMID: 30795528 PMCID: PMC6412287 DOI: 10.3390/ijms20040936] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 01/05/2023] Open
Abstract
Seed development in flowering plants is a critical part of plant life for successful reproduction. The formation of viable seeds requires the synchronous growth and development of the fruit and the three seed structures: the embryo, the endosperm, the seed coat. Molecular communication between these tissues is crucial to coordinate these developmental processes. The phytohormone auxin is a significant player in embryo, seed and fruit development. Its regulated local biosynthesis and its cell-to-cell transport capacity make of auxin the perfect candidate as a signaling molecule to coordinate the growth and development of the embryo, endosperm, seed and fruit. Moreover, newly formed seeds need nutrients and form new carbon sink, generating high sugar flow from vegetative tissues to the seeds. This review will discuss how auxin and sugars may be considered as signaling molecules to coordinate seed and fruit development.
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Affiliation(s)
- Hélène S Robert
- Mendel Centre for Genomics and Proteomics of Plants Systems, CEITEC MU-Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic.
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25
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Erbasol Serbes I, Palovaara J, Groß-Hardt R. Development and function of the flowering plant female gametophyte. Curr Top Dev Biol 2019; 131:401-434. [DOI: 10.1016/bs.ctdb.2018.11.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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26
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RNA-seq Analysis Reveals Gene Expression Profiling of Female Fertile and Sterile Ovules of PinusTabulaeformis Carr. during Free Nuclear Mitosis of the Female Gametophyte. Int J Mol Sci 2018; 19:ijms19082246. [PMID: 30071597 PMCID: PMC6122031 DOI: 10.3390/ijms19082246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 07/22/2018] [Accepted: 07/26/2018] [Indexed: 01/08/2023] Open
Abstract
The development of the female gametophyte (FG) is one of the key processes of life cycle alteration between the haploid gametophyte and the diploid sporophytes in plants and it is required for successful seed development after fertilization. It is well demonstrated that free nuclear mitosis (FNM) of FG is crucial for the development of the ovule. However, studies of the molecular mechanism of ovule and FG development focused mainly on angiosperms, such as Arabidopsis thaliana and further investigation of gymnosperms remains to be completed. Here, Illumina sequencing of six transcriptomic libraries obtained from developing and abortive ovules at different stages during free nuclear mitosis of magagametophyte (FNMM) was used to acquire transcriptome data and gene expression profiles of Pinus tabulaeformis. Six cDNA libraries generated a total of 71.0 million high-quality clean reads that aligned with 63,449 unigenes and the comparison between developing and abortive ovules identified 7174 differentially expressed genes (DEGs). From the functional annotation results, DEGs involved in the cell cycle and phytohormone regulation were highlighted to reveal their biological importance in ovule development. Furthermore, validation of DEGs from the phytohormone signal transduction pathway was performed using quantitative real-time PCR analysis, revealing the dynamics of transcriptional networks and potential key components in the regulation of FG development in P. tabulaeformis were identified. These findings provide new insights into the regulatory mechanisms of ovule development in woody gymnosperms.
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27
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Abstract
The haploid female gametophyte (embryo sac) is an essential reproductive unit of flowering plants, usually comprising four specialized cell types, including the female gametes (egg cell and central cell). The differentiation of these cells relies on spatial signals which pattern the gametophyte along a proximal-distal axis, but the molecular and genetic mechanisms by which cell identities are determined in the embryo sac have long been a mystery. Recent identification of key genes for cell fate specification and their relationship to hormonal signaling pathways that act on positional cues has provided new insights into these processes. A model for differentiation can be devised with egg cell fate as a default state of the female gametophyte and with other cell types specified by the action of spatially regulated factors. Cell-to-cell communication within the gametophyte is also important for maintaining cell identity as well as facilitating fertilization of the female gametes by the male gametes (sperm cells).
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Affiliation(s)
- Debra J Skinner
- Department of Plant Biology, University of California-Davis, Davis, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California-Davis, Davis, USA.,Department of Plant Sciences, University of California-Davis, Davis, USA
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28
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Lora J, Herrero M, Tucker MR, Hormaza JI. The transition from somatic to germline identity shows conserved and specialized features during angiosperm evolution. THE NEW PHYTOLOGIST 2017; 216:495-509. [PMID: 27878998 DOI: 10.1111/nph.14330] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/13/2016] [Indexed: 05/27/2023]
Abstract
How and why specific plant cells adopt germline identity during ovule development has proved challenging to address, and the pathways that are active in the ovules of basal/early-divergent angiosperms possessing a multilayered nucellus are still unclear. Here, we compare megasporogenesis between two early-divergent angiosperms (Annona cherimola and Persea americana) and the evolutionarily derived Arabidopsis thaliana, studying the three-dimensional spatial position of the megaspore mother cell (MMC), the compositional details of the MMC wall and the location of PIN1 expression. Specific wall polymers distinguished the central position of the MMC and its meiotic products from surrounding tissues in early-divergent angiosperms, whereas, in A. thaliana, only callose (in mature MMCs) and arabinogalactan proteins (AGPs) (in megaspores) distinguished the germline. However, PIN1 expression, which regulates polar auxin transport, was observed around the MMC in the single-layer nucellus of A. thaliana and in the multilayered nucellus of A. cherimola, or close to the MMC in P. americana. The data reveal a similar microenvironment in relation to auxin during megasporogenesis in all three species. However, the different wall polymers that mark MMC fate in early-divergent angiosperms may reflect a specific response to mechanical stress during differentiation, or the specific recruitment of polymers to sustain MMC growth.
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Affiliation(s)
- Jorge Lora
- Department of Subtropical Fruits, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Algarrobo-Costa, 29750, Málaga, Spain
| | - María Herrero
- Department of Pomology, Estación Experimental Aula Dei, CSIC, Apdo. 13034, Zaragoza, 50080, Spain
| | - Matthew R Tucker
- Australian Research Council Centre of Excellence in Plant Cell Walls and School of Agriculture, Food and Wine, Waite Research Institute, The University of Adelaide, Glen Osmond, SA, Australia
| | - José I Hormaza
- Department of Subtropical Fruits, Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora' (IHSM-UMA-CSIC), Algarrobo-Costa, 29750, Málaga, Spain
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29
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Live-Cell Imaging of Auxin and Cytokinin Signaling in Maize Female Gametophytes. Methods Mol Biol 2017; 1669:95-101. [PMID: 28936653 DOI: 10.1007/978-1-4939-7286-9_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
The plant life cycle is characterized by the alternation of generations between genetically active diploid sporophytes and haploid gametophytes. The gametophytes of flowering plants are sexually dimorphic. While the male gametophyte consists of only three cells (two sperm and a vegetative cell) and is released by the parent sporophyte, the female gametophyte (or embryo sac) is more complex and remains imbedded within diploid sporophyte tissues. In maize, the female gametophyte is embedded in a large ovule surrounded with multiple nucellar cell layers impeding live-cell imaging approaches to study embryo sac functions. Here, we describe a simple protocol to visualize embryo sacs with hormonal fluorescent reporters by increasing accessibility of the female gametophyte. The method described is applicable for visualization of any fluorescent embryo sac reporter. The embryo sacs visualization method developed for maize could be extended to facilitate visualization of embryos sac in other important cereals like wheat, rice, and oats.
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30
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Rojas-Gracia P, Roque E, Medina M, Rochina M, Hamza R, Angarita-Díaz MP, Moreno V, Pérez-Martín F, Lozano R, Cañas L, Beltrán JP, Gómez-Mena C. The parthenocarpic hydra mutant reveals a new function for a SPOROCYTELESS-like gene in the control of fruit set in tomato. THE NEW PHYTOLOGIST 2017; 214:1198-1212. [PMID: 28134991 DOI: 10.1111/nph.14433] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 12/12/2016] [Indexed: 05/20/2023]
Abstract
Fruit set is an essential process to ensure successful sexual plant reproduction. The development of the flower into a fruit is actively repressed in the absence of pollination. However, some cultivars from a few species are able to develop seedless fruits overcoming the standard restriction of unpollinated ovaries to growth. We report here the identification of the tomato hydra mutant that produces seedless (parthenocarpic) fruits. Seedless fruit production in hydra plants is linked to the absence of both male and female sporocyte development. The HYDRA gene is therefore essential for the initiation of sporogenesis in tomato. Using positional cloning, virus-induced gene silencing and expression analysis experiments, we identified the HYDRA gene and demonstrated that it encodes the tomato orthologue of SPOROCYTELESS/NOZZLE (SPL/NZZ) of Arabidopsis. We found that the precocious growth of the ovary is associated with changes in the expression of genes involved in gibberellin (GA) metabolism. Our results support the conservation of the function of SPL-like genes in the control of sporogenesis in plants. Moreover, this study uncovers a new function for the tomato SlSPL/HYDRA gene in the control of fruit initiation.
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Affiliation(s)
- Pilar Rojas-Gracia
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - Edelin Roque
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - Mónica Medina
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - Maricruz Rochina
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - Rim Hamza
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - María Pilar Angarita-Díaz
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - Vicente Moreno
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - Fernando Pérez-Martín
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, Ctra de Sacramento s/n, 04120, Almería, Spain
| | - Rafael Lozano
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, Ctra de Sacramento s/n, 04120, Almería, Spain
| | - Luis Cañas
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - José Pío Beltrán
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
| | - Concepción Gómez-Mena
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), CSIC-UPV, Ciudad Politécnica de la Innovación, Edf. 8E. C/Ing. Fausto Elio s/n, Valencia, 46011, Spain
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31
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Zhou LZ, Juranić M, Dresselhaus T. Germline Development and Fertilization Mechanisms in Maize. MOLECULAR PLANT 2017; 10:389-401. [PMID: 28267957 DOI: 10.1016/j.molp.2017.01.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 01/29/2017] [Accepted: 01/31/2017] [Indexed: 05/06/2023]
Abstract
Maize is the most important agricultural crop used for food, feed, and biofuel as well as a raw material for industrial products such as packaging material. To increase yield and to overcome hybridization barriers, studies of maize gamete development, the pollen tube journey, and fertilization mechanisms were initiated more than a century ago. In this review, we summarize and discuss our current understanding of the regulatory components for germline development including sporogenesis and gametogenesis, the progamic phase of pollen germination and pollen tube growth and guidance, as well as fertilization mechanisms consisting of pollen tube arrival and reception, sperm cell release, fusion with the female gametes, and egg cell activation. Mechanisms of asexual seed development are not considered here. While only a few molecular players involved in these processes have been described to date and the underlying mechanisms are far from being understood, maize now represents a spearhead of reproductive research for all grass species. Recent development of essentially improved transformation and gene-editing systems may boost research in this area in the near future.
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Affiliation(s)
- Liang-Zi Zhou
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Martina Juranić
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
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32
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Doll NM, Depège-Fargeix N, Rogowsky PM, Widiez T. Signaling in Early Maize Kernel Development. MOLECULAR PLANT 2017; 10:375-388. [PMID: 28267956 DOI: 10.1016/j.molp.2017.01.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 01/18/2017] [Accepted: 01/19/2017] [Indexed: 05/26/2023]
Abstract
Developing the next plant generation within the seed requires the coordination of complex programs driving pattern formation, growth, and differentiation of the three main seed compartments: the embryo (future plant), the endosperm (storage compartment), representing the two filial tissues, and the surrounding maternal tissues. This review focuses on the signaling pathways and molecular players involved in early maize kernel development. In the 2 weeks following pollination, functional tissues are shaped from single cells, readying the kernel for filling with storage compounds. Although the overall picture of the signaling pathways regulating embryo and endosperm development remains fragmentary, several types of molecular actors, such as hormones, sugars, or peptides, have been shown to be involved in particular aspects of these developmental processes. These molecular actors are likely to be components of signaling pathways that lead to transcriptional programming mediated by transcriptional factors. Through the integrated action of these components, multiple types of information received by cells or tissues lead to the correct differentiation and patterning of kernel compartments. In this review, recent advances regarding the four types of molecular actors (hormones, sugars, peptides/receptors, and transcription factors) involved in early maize development are presented.
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Affiliation(s)
- Nicolas M Doll
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342 Lyon, France
| | - Nathalie Depège-Fargeix
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342 Lyon, France
| | - Peter M Rogowsky
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342 Lyon, France
| | - Thomas Widiez
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, 69342 Lyon, France.
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33
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Tedeschi F, Rizzo P, Rutten T, Altschmied L, Bäumlein H. RWP-RK domain-containing transcription factors control cell differentiation during female gametophyte development in Arabidopsis. THE NEW PHYTOLOGIST 2017; 213:1909-1924. [PMID: 27870062 DOI: 10.1111/nph.14293] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/17/2016] [Indexed: 05/02/2023]
Abstract
The formation of gametes is a prerequisite for any sexually reproducing organism in order to complete its life cycle. In plants, female gametes are formed in a multicellular tissue, the female gametophyte or embryo sac. Although the events leading to the formation of the female gametophyte have been morphologically characterized, the molecular control of embryo sac development remains elusive. We used single and double mutants as well as cell-specific marker lines to characterize a novel class of gene regulators in Arabidopsis thaliana, the RWP-RK domain-containing (RKD) transcription factors. Morphological and histological analyses were conducted using confocal laser scanning and differential interference contrast microscopy. Gene expression and transcriptome analyses were performed using quantitative reverse transcription-PCR and RNA sequencing, respectively. Our results showed that RKD genes are expressed during distinct stages of embryo sac development. Morphological analysis of the mutants revealed severe distortions in gametophyte polarity and cell differentiation. Transcriptome analysis revealed changes in the expression of several gametophyte-specific gene families (RKD2 and RKD3) and ovule development-specific genes (RKD3), and identified pleiotropic effects on phytohormone pathways (RKD5). Our data provide novel insight into the regulatory control of female gametophyte development. RKDs are involved in the control of cell differentiation and are required for normal gametophytic development.
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Affiliation(s)
- Francesca Tedeschi
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Seeland, OT Gatersleben, Germany
| | - Paride Rizzo
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Seeland, OT Gatersleben, Germany
| | - Twan Rutten
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Seeland, OT Gatersleben, Germany
| | - Lothar Altschmied
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Seeland, OT Gatersleben, Germany
| | - Helmut Bäumlein
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Seeland, OT Gatersleben, Germany
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34
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Larsson E, Vivian-Smith A, Offringa R, Sundberg E. Auxin Homeostasis in Arabidopsis Ovules Is Anther-Dependent at Maturation and Changes Dynamically upon Fertilization. FRONTIERS IN PLANT SCIENCE 2017; 8:1735. [PMID: 29067034 PMCID: PMC5641375 DOI: 10.3389/fpls.2017.01735] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 09/22/2017] [Indexed: 05/20/2023]
Abstract
The plant hormone auxin is a vital component for plant reproduction as it regulates the development of both male and female reproductive organs, including ovules and gynoecia. Furthermore, auxin plays important roles in the development and growth of seeds and fruits. Auxin responses can be detected in ovules shortly after fertilization, and it has been suggested that this accumulation is a prerequisite for the developmental reprogramming of the ovules to seeds, and of the gynoecium to a fruit. However, the roles of auxin at the final stages of ovule development, and the sources of auxin leading to the observed responses in ovules after fertilization have remained elusive. Here we have characterized the auxin readout in Arabidopsis ovules, at the pre-anthesis, anthesis and in the immediate post-fertilization stages, using the R2D2 auxin sensor. In addition we have mapped the expression of auxin biosynthesis and conjugation genes, as well as that of auxin transporting proteins, during the same developmental stages. These analyses reveal specific spatiotemporal patterns of the different auxin homeostasis regulators. Auxin biosynthesis genes and auxin transport proteins define a pre-patterning of vascular cell identity in the pre-anthesis funiculus. Furthermore, our data suggests that auxin efflux from the ovule is restricted in an anther-dependent manner, presumably to synchronize reproductive organ development and thereby optimizing the chances of successful fertilization. Finally, de novo auxin biosynthesis together with reduced auxin conjugation and transport result in an enhanced auxin readout throughout the sporophytic tissues of the ovules soon after fertilization. Together, our results suggest a sophisticated set of regulatory cascades that allow successful fertilization and the subsequent transition of the female reproductive structures into seeds and fruits.
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Affiliation(s)
- Emma Larsson
- Institute of Biology Leiden, Plant Developmental Genetics, Leiden University, Leiden, Netherlands
- Department of Plant Biology, BioCentre and Linnean Centre for Plant Biology in Uppsala, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- *Correspondence: Emma Larsson, Eva Sundberg,
| | - Adam Vivian-Smith
- Forest Genetics and Biodiversity, Norwegian Institute of Bioeconomy Research, Ås, Norway
| | - Remko Offringa
- Institute of Biology Leiden, Plant Developmental Genetics, Leiden University, Leiden, Netherlands
| | - Eva Sundberg
- Department of Plant Biology, BioCentre and Linnean Centre for Plant Biology in Uppsala, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- *Correspondence: Emma Larsson, Eva Sundberg,
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Morales-Tapia A, Cruz-Ramírez A. Computational Modeling of Auxin: A Foundation for Plant Engineering. FRONTIERS IN PLANT SCIENCE 2016; 7:1881. [PMID: 28066453 PMCID: PMC5168462 DOI: 10.3389/fpls.2016.01881] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 11/29/2016] [Indexed: 05/29/2023]
Abstract
Since the development of agriculture, humans have relied on the cultivation of plants to satisfy our increasing demand for food, natural products, and other raw materials. As we understand more about plant development, we can better manipulate plants to fulfill our particular needs. Auxins are a class of simple metabolites that coordinate many developmental activities like growth and the appearance of functional structures in plants. Computational modeling of auxin has proven to be an excellent tool in elucidating many mechanisms that underlie these developmental events. Due to the complexity of these mechanisms, current modeling efforts are concerned only with single phenomena focused on narrow spatial and developmental contexts; but a general model of plant development could be assembled by integrating the insights from all of them. In this perspective, we summarize the current collection of auxin-driven computational models, focusing on how they could come together into a single model for plant development. A model of this nature would allow researchers to test hypotheses in silico and yield accurate predictions about the behavior of a plant under a given set of physical and biochemical constraints. It would also provide a solid foundation toward the establishment of plant engineering, a proposed discipline intended to enable the design and production of plants that exhibit an arbitrarily defined set of features.
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36
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Yang L, Wu Y, Yu M, Mao B, Zhao B, Wang J. Genome-wide transcriptome analysis of female-sterile rice ovule shed light on its abortive mechanism. PLANTA 2016; 244:1011-1028. [PMID: 27357232 DOI: 10.1007/s00425-016-2563-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 06/23/2016] [Indexed: 05/03/2023]
Abstract
The comprehensive transcriptome analysis of rice female-sterile line and wild-type line ovule provides an important clue for exploring the regulatory network of the formation of rice fertile female gametophyte. Ovules are the female reproductive tissues of rice (Oryza sativa L.) and play a major role in sexual reproduction. To investigate the potential mechanism of rice female gametophyte fertility, we used RNA sequencing, combined with genetic subtraction, to compare the transcriptome of the ovules of a high-frequency female-sterile line (fsv1) and a rice wild-type line (Gui 99) during ovule development. Ovules were harvested at three developmental stages: ovule containing megaspore mother cell in meiosis process (stage 1), ovule containing functional megaspore in mitosis process (stage 2), and ovule containing mature female gametophyte (stage 3). Six cDNA libraries generated a total of 42.2 million high-quality clean reads that aligned with 30,204 genes. The comparison between the fsv1 and Gui 99 ovules identified a large number of differentially expressed genes (DEGs), i.e., 45, 495, and 932 DEGs at the three ovule developmental stages, respectively. From the comparison of the two rice lines, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and MapMan analyses indicated that a large number of DEGs associated with starch and sucrose metabolism, plant hormone signal transduction, protein modification and degradation, oxidative phosphorylation, and receptor kinase. These DEGs might play roles in ovule development and fertile female gametophyte formation. Many transcription factor genes and epigenetic-related genes also exhibit different expression patterns and significantly different expression levels in two rice lines during ovule development, which might provide important information regarding the abortive mechanism of the female gametophyte in rice.
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Affiliation(s)
- Liyu Yang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ya Wu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Meiling Yu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Bigang Mao
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China
| | - Bingran Zhao
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, 410125, China.
| | - Jianbo Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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Zürcher E, Liu J, di Donato M, Geisler M, Müller B. Plant development regulated by cytokinin sinks. Science 2016; 353:1027-1030. [PMID: 27701112 DOI: 10.1126/science.aaf7254] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/04/2016] [Indexed: 01/29/2023]
Abstract
Morphogenetic signals control the patterning of multicellular organisms. Cytokinins are mobile signals that are perceived by subsets of plant cells. We found that the responses to cytokinin signaling during Arabidopsis development are constrained by the transporter PURINE PERMEASE 14 (PUP14). In our experiments, the expression of PUP14 was inversely correlated to the cytokinin signaling readout. Loss of PUP14 function allowed ectopic cytokinin signaling accompanied by aberrant morphogenesis in embryos, roots, and the shoot apical meristem. PUP14 protein localized to the plasma membrane and imported bioactive cytokinins, thus depleting apoplastic cytokinin pools and inhibiting perception by plasma membrane-localized cytokinin sensors to create a sink for active ligands. We propose that the spatiotemporal cytokinin sink patterns established by PUP14 determine the cytokinin signaling landscape that shapes the morphogenesis of land plants.
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Affiliation(s)
- Evelyne Zürcher
- Zürich-Basel Plant Science Center, Department of Plant and Microbial Biology, University of Zürich, 8008 Zürich, Switzerland
| | - Jingchun Liu
- Zürich-Basel Plant Science Center, Department of Plant and Microbial Biology, University of Zürich, 8008 Zürich, Switzerland
| | - Martin di Donato
- Plant Biology, Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Markus Geisler
- Plant Biology, Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Bruno Müller
- Zürich-Basel Plant Science Center, Department of Plant and Microbial Biology, University of Zürich, 8008 Zürich, Switzerland.
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38
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Palovaara J, de Zeeuw T, Weijers D. Tissue and Organ Initiation in the Plant Embryo: A First Time for Everything. Annu Rev Cell Dev Biol 2016; 32:47-75. [PMID: 27576120 DOI: 10.1146/annurev-cellbio-111315-124929] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Land plants can grow to tremendous body sizes, yet even the most complex architectures are the result of iterations of the same developmental processes: organ initiation, growth, and pattern formation. A central question in plant biology is how these processes are regulated and coordinated to allow for the formation of ordered, 3D structures. All these elementary processes first occur in early embryogenesis, during which, from a fertilized egg cell, precursors for all major tissues and stem cells are initiated, followed by tissue growth and patterning. Here we discuss recent progress in our understanding of this phase of plant life. We consider the cellular basis for multicellular development in 3D and focus on the genetic regulatory mechanisms that direct specific steps during early embryogenesis.
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Affiliation(s)
- Joakim Palovaara
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands;
| | - Thijs de Zeeuw
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands;
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands;
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39
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Figueiredo DD, Köhler C. Bridging the generation gap: communication between maternal sporophyte, female gametophyte and fertilization products. CURRENT OPINION IN PLANT BIOLOGY 2016; 29:16-20. [PMID: 26658334 DOI: 10.1016/j.pbi.2015.10.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 10/16/2015] [Accepted: 10/19/2015] [Indexed: 05/08/2023]
Abstract
In seed plants, as in placental animals, gamete formation and zygotic development take place within the parental tissues. To ensure timely onset and to coordinate the development of the new generation, communication between the parent plant with the filial tissues and its precursors is of utmost importance. During female gametogenesis the maternal tissues tightly regulate megagametophyte formation and the interplay between the sporophyte and the fertilization products, embryo and endosperm, has major implications in the formation of a viable seed. We review the current knowledge on these interactions and highlight the many questions that still remain unanswered, in particular the nature of the pathways involved in these signaling events.
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Affiliation(s)
- Duarte D Figueiredo
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, Uppsala, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, Uppsala, Sweden.
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40
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Schmid MW, Schmidt A, Grossniklaus U. The female gametophyte: an emerging model for cell type-specific systems biology in plant development. FRONTIERS IN PLANT SCIENCE 2015; 6:907. [PMID: 26579157 PMCID: PMC4630298 DOI: 10.3389/fpls.2015.00907] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/10/2015] [Indexed: 05/03/2023]
Abstract
Systems biology, a holistic approach describing a system emerging from the interactions of its molecular components, critically depends on accurate qualitative determination and quantitative measurements of these components. Development and improvement of large-scale profiling methods ("omics") now facilitates comprehensive measurements of many relevant molecules. For multicellular organisms, such as animals, fungi, algae, and plants, the complexity of the system is augmented by the presence of specialized cell types and organs, and a complex interplay within and between them. Cell type-specific analyses are therefore crucial for the understanding of developmental processes and environmental responses. This review first gives an overview of current methods used for large-scale profiling of specific cell types exemplified by recent advances in plant biology. The focus then lies on suitable model systems to study plant development and cell type specification. We introduce the female gametophyte of flowering plants as an ideal model to study fundamental developmental processes. Moreover, the female reproductive lineage is of importance for the emergence of evolutionary novelties such as an unequal parental contribution to the tissue nurturing the embryo or the clonal production of seeds by asexual reproduction (apomixis). Understanding these processes is not only interesting from a developmental or evolutionary perspective, but bears great potential for further crop improvement and the simplification of breeding efforts. We finally highlight novel methods, which are already available or which will likely soon facilitate large-scale profiling of the specific cell types of the female gametophyte in both model and non-model species. We conclude that it may take only few years until an evolutionary systems biology approach toward female gametogenesis may decipher some of its biologically most interesting and economically most valuable processes.
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Affiliation(s)
| | | | - Ueli Grossniklaus
- Department of Plant & Microbial Biology and Zurich-Basel Plant Science Center, University of ZurichZurich, Switzerland
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41
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Li L, He Y, Wang Y, Zhao S, Chen X, Ye T, Wu Y, Wu Y. Arabidopsis PLC2 is involved in auxin-modulated reproductive development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:504-15. [PMID: 26340337 DOI: 10.1111/tpj.13016] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 08/22/2015] [Accepted: 08/26/2015] [Indexed: 05/08/2023]
Abstract
Phospholipase C (PLC) is an enzyme that plays crucial roles in various signal transduction pathways in mammalian cells. However, the role of PLC in plant development is poorly understood. Here we report involvement of PLC2 in auxin-mediated reproductive development in Arabidopsis. Disruption of PLC2 led to sterility, indicating a significant role for PLC2 in reproductive development. Development of both male and female gametophytes was severely perturbed in plc2 mutants. Moreover, elevated auxin levels were observed in plc2 floral tissues, suggesting that the infertility of plc2 plants may be associated with increased auxin concentrations in the reproductive organs. We show that expression levels of the auxin reporters DR5:GUS and DR5:GFP were elevated in plc2 anthers and ovules. In addition, we found that expression of the auxin biosynthetic YUCCA genes was increased in plc2 plants. We conclude that PLC2 is involved in auxin biosynthesis and signaling, thus modulating development of both male and female gametophytes in Arabidopsis.
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Affiliation(s)
- Lin Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yuqing He
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yarui Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Shujuan Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xi Chen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Tiantian Ye
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yuxuan Wu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yan Wu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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42
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Robert HS, Crhak Khaitova L, Mroue S, Benková E. The importance of localized auxin production for morphogenesis of reproductive organs and embryos in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:5029-42. [PMID: 26019252 DOI: 10.1093/jxb/erv256] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Plant sexual reproduction involves highly structured and specialized organs: stamens (male) and gynoecia (female, containing ovules). These organs synchronously develop within protective flower buds, until anthesis, via tightly coordinated mechanisms that are essential for effective fertilization and production of viable seeds. The phytohormone auxin is one of the key endogenous signalling molecules controlling initiation and development of these, and other, plant organs. In particular, its uneven distribution, resulting from tightly controlled production, metabolism and directional transport, is an important morphogenic factor. In this review we discuss how developmentally controlled and localized auxin biosynthesis and transport contribute to the coordinated development of plants' reproductive organs, and their fertilized derivatives (embryos) via the regulation of auxin levels and distribution within and around them. Current understanding of the links between de novo local auxin biosynthesis, auxin transport and/or signalling is presented to highlight the importance of the non-cell autonomous action of auxin production on development and morphogenesis of reproductive organs and embryos. An overview of transcription factor families, which spatiotemporally define local auxin production by controlling key auxin biosynthetic enzymes, is also presented.
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Affiliation(s)
- Hélène S Robert
- Mendel Centre for Genomics and Proteomics of Plants Systems, CEITEC MU - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Lucie Crhak Khaitova
- Mendel Centre for Genomics and Proteomics of Plants Systems, CEITEC MU - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Souad Mroue
- Mendel Centre for Genomics and Proteomics of Plants Systems, CEITEC MU - Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Eva Benková
- Institute of Science and Technology Austria (IST Austria), 3400 Klosterneuburg, Austria
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43
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Patterning of the angiosperm female gametophyte through the prism of theoretical paradigms. Biochem Soc Trans 2015; 42:332-9. [PMID: 24646240 DOI: 10.1042/bst20140036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The FG (female gametophyte) of flowering plants (angiosperms) is a simple highly polar structure composed of only a few cell types. The FG develops from a single cell through mitotic divisions to generate, depending on the species, four to 16 nuclei in a syncytium. These nuclei are then partitioned into three or four distinct cell types. The mechanisms underlying the specification of the nuclei in the FG has been a focus of research over the last decade. Nevertheless, we are far from understanding the patterning mechanisms that govern cell specification. Although some results were previously interpreted in terms of static positional information, several lines of evidence now show that local interactions are important. In the present article, we revisit the available data on developmental mutants and cell fate markers in the light of theoretical frameworks for biological patterning. We argue that a further dissection of the mechanisms may be impeded by the combinatorial and dynamical nature of developmental cues. However, accounting for these properties of developing systems is necessary to disentangle the diversity of the phenotypic manifestations of the underlying molecular interactions.
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44
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Abstract
Plant hormones have been shown to regulate key processes during embryogenesis in the model plant Arabidopsis thaliana, but the mechanisms that determine the peculiar embryo pattern formation of monocots are largely unknown. Using the auxin and cytokinin response markers DR5 and TCSv2 (two-component system, cytokinin-responsive promoter version #2), as well as the auxin efflux carrier protein PIN1a (PINFORMED1a), we have studied the hormonal response during early embryogenesis (zygote towards transition stage) in the model and crop plant maize. Compared with the hormonal response in Arabidopsis, we found that detectable hormone activities inside the developing maize embryo appeared much later. Our observations indicate further an important role of auxin, PIN1a and cytokinin in endosperm formation shortly after fertilization. Apparent auxin signals within adaxial endosperm cells and cytokinin responses in the basal endosperm transfer layer as well as chalazal endosperm are characteristic for early seed development in maize. Moreover, auxin signalling in endosperm cells is likely to be involved in exogenous embryo patterning as auxin responses in the endosperm located around the embryo proper correlate with adaxial embryo differentiation and outgrowth. Overall, the comparison between Arabidopsis and maize hormone response and flux suggests intriguing mechanisms in monocots that are used to direct their embryo patterning, which is significantly different from that of eudicots.
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45
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Panoli A, Martin MV, Alandete-Saez M, Simon M, Neff C, Swarup R, Bellido A, Yuan L, Pagnussat GC, Sundaresan V. Auxin Import and Local Auxin Biosynthesis Are Required for Mitotic Divisions, Cell Expansion and Cell Specification during Female Gametophyte Development in Arabidopsis thaliana. PLoS One 2015; 10:e0126164. [PMID: 25970627 PMCID: PMC4430233 DOI: 10.1371/journal.pone.0126164] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 03/29/2015] [Indexed: 11/18/2022] Open
Abstract
The female gametophyte of flowering plants, called the embryo sac, develops from a haploid cell named the functional megaspore, which is specified after meiosis by the diploid sporophyte. In Arabidopsis, the functional megaspore undergoes three syncitial mitotic divisions followed by cellularization to form seven cells of four cell types including two female gametes. The plant hormone auxin is important for sporophytic developmental processes, and auxin levels are known to be regulated by biosynthesis and transport. Here, we investigated the role of auxin biosynthetic genes and auxin influx carriers in embryo sac development. We find that genes from the YUCCA/TAA pathway (YUC1, YUC2, YUC8, TAA1, TAR2) are expressed asymmetrically in the developing ovule and embryo sac from the two-nuclear syncitial stage until cellularization. Mutants for YUC1 and YUC2 exhibited defects in cell specification, whereas mutations in YUC8, as well as mutations in TAA1 and TAR2, caused defects in nuclear proliferation, vacuole formation and anisotropic growth of the embryo sac. Additionally, expression of the auxin influx carriers AUX1 and LAX1 were observed at the micropylar pole of the embryo sac and in the adjacent cells of the ovule, and the aux1 lax1 lax2 triple mutant shows multiple gametophyte defects. These results indicate that both localized auxin biosynthesis and auxin import, are required for mitotic divisions, cell expansion and patterning during embryo sac development.
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Affiliation(s)
- Aneesh Panoli
- Department of Plant Biology, University of California Davis, Davis, California, 95616, United States of America
| | - Maria Victoria Martin
- Institute of Biological Research IIB-CONICET, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina
| | - Monica Alandete-Saez
- Department of Plant Biology, University of California Davis, Davis, California, 95616, United States of America
- PIPRA, University of California Davis, Davis, California, 95616, United States of America
| | - Marissa Simon
- Department of Plant Biology, University of California Davis, Davis, California, 95616, United States of America
| | - Christina Neff
- Department of Plant Biology, University of California Davis, Davis, California, 95616, United States of America
| | - Ranjan Swarup
- University of Nottingham, Nottingham, United Kingdom
| | - Andrés Bellido
- Institute of Biological Research IIB-CONICET, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina
| | - Li Yuan
- Department of Plant Biology, University of California Davis, Davis, California, 95616, United States of America
| | - Gabriela C. Pagnussat
- Institute of Biological Research IIB-CONICET, Universidad Nacional de Mar del Plata, 7600, Mar del Plata, Argentina
- * E-mail: (GCP); (VS)
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California Davis, Davis, California, 95616, United States of America
- Department of Plant Sciences, University of California Davis, Davis, California, 95616, United States of America
- * E-mail: (GCP); (VS)
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46
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Schmidt A, Schmid MW, Grossniklaus U. Plant germline formation: common concepts and developmental flexibility in sexual and asexual reproduction. Development 2015; 142:229-41. [PMID: 25564620 DOI: 10.1242/dev.102103] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The life cycle of flowering plants alternates between two heteromorphic generations: a diploid sporophytic generation and a haploid gametophytic generation. During the development of the plant reproductive lineages - the germlines - typically, single sporophytic (somatic) cells in the flower become committed to undergo meiosis. The resulting spores subsequently develop into highly polarized and differentiated haploid gametophytes that harbour the gametes. Recent studies have provided insights into the genetic basis and regulatory programs underlying cell specification and the acquisition of reproductive fate during both sexual reproduction and asexual (apomictic) reproduction. As we review here, these recent advances emphasize the importance of transcriptional, translational and post-transcriptional regulation, and the role of epigenetic regulatory pathways and hormonal activity.
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Affiliation(s)
- Anja Schmidt
- Institute of Plant Biology and Zürich-Basel Plant Science Centre, University of Zürich, Zollikerstrasse 107, Zürich CH-8008, Switzerland
| | - Marc W Schmid
- Institute of Plant Biology and Zürich-Basel Plant Science Centre, University of Zürich, Zollikerstrasse 107, Zürich CH-8008, Switzerland
| | - Ueli Grossniklaus
- Institute of Plant Biology and Zürich-Basel Plant Science Centre, University of Zürich, Zollikerstrasse 107, Zürich CH-8008, Switzerland
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47
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Chettoor AM, Evans MMS. Correlation between a loss of auxin signaling and a loss of proliferation in maize antipodal cells. FRONTIERS IN PLANT SCIENCE 2015; 6:187. [PMID: 25859254 PMCID: PMC4374392 DOI: 10.3389/fpls.2015.00187] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/08/2015] [Indexed: 05/03/2023]
Abstract
The plant life cycle alternates between two genetically active generations: the diploid sporophyte and the haploid gametophyte. In angiosperms the gametophytes are sexually dimorphic and consist of only a few cells. The female gametophyte, or embryo sac, is comprised of four cell types: two synergids, an egg cell, a central cell, and a variable number of antipodal cells. In some species the antipodal cells are indistinct and fail to proliferate, so many aspects of antipodal cell function and development have been unclear. In maize and many other grasses, the antipodal cells proliferate to produce a highly distinct cluster at the chalazal end of the embryo sac that persists at the apex of the endosperm after fertilization. The antipodal cells are a site of auxin accumulation in the maize embryo sac. Analysis of different families of genes involved in auxin biosynthesis, distribution, and signaling for expression in the embryo sac demonstrates that all steps are expressed within the embryo sac. In contrast to auxin signaling, cytokinin signaling is absent in the embryo sac and instead occurs adjacent to but outside of the antipodal cells. Mutant analysis shows a correlation between a loss of auxin signaling and a loss of proliferation of the antipodal cells. The leaf polarity mutant Laxmidrib1 causes a lack of antipodal cell proliferation coupled with a loss of DR5 and PIN1a expression in the antipodal cells.
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Affiliation(s)
| | - Matthew M. S. Evans
- *Correspondence: Matthew M. S. Evans, Department of Plant Biology, Carnegie Institution for Science, 260 Panama St. Stanford, CA, 94305, USA
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48
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Twin plants from supernumerary egg cells in Arabidopsis. Curr Biol 2014; 25:225-230. [PMID: 25544612 DOI: 10.1016/j.cub.2014.11.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/20/2014] [Accepted: 11/07/2014] [Indexed: 01/19/2023]
Abstract
Sexual reproduction of flowering plants is distinguished by double fertilization—the two sperm cells delivered by a pollen tube fuse with the two gametic cells of the female gametophyte, the egg and the central cell—inside the ovule to give rise to the embryo and the nutritive endosperm, respectively. The pollen tube is attracted by nongametic synergid cells, and how these two cells of the female gametophyte are specified is currently unclear. Here, we show that ALTERED MERISTEM PROGRAM 1 (AMP1), encoding a protein associated with the endoplasmic reticulum, is required for synergid cell fate during Arabidopsis female gametophyte development. Loss of AMP1 function leads to supernumerary egg cells at the expense of synergids, enabling the generation of dizygotic twins. However, if twin embryos are formed, endosperm formation is prevented, eventually resulting in ovule abortion. The latter can be overcome by the delivery of supernumerary sperm cells in tetraspore (tes) pollen, enabling the formation of twin plants. Thus, both primary and supernumerary egg cells are fully functional in amp1 mutant plants. Sporophytic AMP1 expression is sufficient to prevent cell-fate change of synergids, indicating that one or more AMP1-dependent mobile signals from outside the female gametophyte can contribute to its patterning, in addition to the previously reported lateral inhibition between gametophytic cells. Our results provide insight into the mechanism of synergid fate specification and emphasize the importance of specifying only one egg cell within the female gametophyte to ensure central-cell fertilization by the second sperm cell.
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49
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Sehgal A, Mann N, Mohan Ram HY. Structural and developmental variability in the female gametophyte of Griffithella hookeriana, Polypleurum stylosum, and Zeylanidium lichenoides and its bearing on the occurrence of single fertilization in Podostemaceae. PLANT REPRODUCTION 2014; 27:205-23. [PMID: 25394544 DOI: 10.1007/s00497-014-0252-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 10/30/2014] [Indexed: 05/20/2023]
Abstract
Angiosperms are characterized by the phenomenon of double fertilization with Podostemaceae as an exception that appears to extend to the entire family. Our earlier work demonstrated the cause of failure of double fertilization and ascertained the occurrence of single fertilization in Dalzellia zeylanica (Tristichoideae, Podostemaceae). In continuation with this work, three more members, i.e., Griffithella hookeriana (Tul.) Warming, Polypleurum stylosum (Wight) Hall, and Zeylanidium lichenoides (Kurz) Engl. (Podostemoideae), have been investigated in the present work. We studied the ontogenetic development of female gametophyte and tracked the path of the two sperm cells from the time of their formation in the pollen tube through their entry into the synergid and gamete fusion. We report the occurrence of a remarkably reduced 3-nucleate, 3-celled mature female gametophyte consisting of an egg cell and two synergids in all the three genera. Interestingly, the central cell is formed during female gametophyte development, but exhibits a species-specific, limited life span, and eventually degenerates prior to the entry of the pollen tube into the synergid, resulting in a failure of double fertilization. Sperm dimorphism on the basis of fluorochrome stainability has been recorded in Z. lichenoides. Further, morphogenetic constraints on the part of male (sperm selection, functional reductionism) and female gametophyte (structural reductionism, inaccessibility of central cell) presumably ensure the failure of double fertilization in these species. Thus, loss of double fertilization in this family is likely a derived condition.
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Affiliation(s)
- Anita Sehgal
- Department of Botany, Miranda House, University of Delhi, Delhi, 110007, India,
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