1
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Rauf A, Wang A, Li Y, Lian Z, Wei S, Jabbar K, Wisal M, Khan I, Khalid M, Li J. The male germ unit association is independently regulated of GUM in Arabidopsis thaliana. PLANT DIRECT 2024; 8:e624. [PMID: 39076347 PMCID: PMC11286290 DOI: 10.1002/pld3.624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/17/2024] [Accepted: 07/06/2024] [Indexed: 07/31/2024]
Abstract
Cytoplasmic projections (CPs) formed by the generative and sperm cells link the male gametes with the vegetative cell (VC) nucleus, which are required to build the male germ unit (MGU) assemblage in the angiosperm pollen grain. As molecular and genetic controls underlying CP development and formation of the MGU are unknown, it was hypothesized that physical association between germ cells and the VC nucleus might be lost in germ unit malformed (gum) mutants or in those which either block generative cell (GC) division or that additionally prevent gamete differentiation. In vivo, analysis of marked cellular components demonstrated a linkage of sperm cells (SCs) and the VC nucleus in gum mutant alleles despite their increased physical separation. Similarly, for several independent classes of bicellular pollen mutants, undivided GCs were associated with the VC nucleus like GCs in wild-type pollen. We conclude that the early formation of GC CPs to establish the MGU is regulated independently of DUO1-DAZ1 and DUO3 transcription factors as well as cyclin-dependent kinase function (CDKA;1). As the absence of cytoplasmic protrusion was expected in the gum mutants in Arabidopsis, early histological studies reported temporal disappearance of cytoplasmic protrusion in several organisms. Our findings demonstrated the striking importance of live imaging to verify the broad conservation of the persistent MGU contact in all the angiosperms and its important role in successful double fertilization.
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Affiliation(s)
- Abdur Rauf
- National Key Laboratory for Tropical Crop Breeding, Tropical Crop Genetic Resources Institute Chinese Academy of Tropical Agricultural Sciences Sanya/Haikou Hainan China
- Garden Campus, Department of Botany Abdul Wali Khan University Mardan KP Pakistan
- Department of Genetic and Genome Biology University of Leicester UK
- Hainan Banana Healthy Seedling Propagation Engineering Research Center, Haikou Experimental Station Chinese Academy of Tropical Agricultural Sciences Haikou Hainan China
| | - Anbang Wang
- National Key Laboratory for Tropical Crop Breeding, Tropical Crop Genetic Resources Institute Chinese Academy of Tropical Agricultural Sciences Sanya/Haikou Hainan China
| | - Yujia Li
- National Key Laboratory for Tropical Crop Breeding, Tropical Crop Genetic Resources Institute Chinese Academy of Tropical Agricultural Sciences Sanya/Haikou Hainan China
| | - Zhihao Lian
- National Key Laboratory for Tropical Crop Breeding, Tropical Crop Genetic Resources Institute Chinese Academy of Tropical Agricultural Sciences Sanya/Haikou Hainan China
| | - Shouxing Wei
- National Key Laboratory for Tropical Crop Breeding, Tropical Crop Genetic Resources Institute Chinese Academy of Tropical Agricultural Sciences Sanya/Haikou Hainan China
| | | | - Muhammad Wisal
- Garden Campus, Department of Botany Abdul Wali Khan University Mardan KP Pakistan
| | - Ikramullah Khan
- Garden Campus, Department of Botany Abdul Wali Khan University Mardan KP Pakistan
| | - Muhammad Khalid
- Department of Biology, College of Science, Mathematics and Technology Wenzhou-Kean University Wenzhou China
| | - Jingyang Li
- National Key Laboratory for Tropical Crop Breeding, Tropical Crop Genetic Resources Institute Chinese Academy of Tropical Agricultural Sciences Sanya/Haikou Hainan China
- Hainan Banana Healthy Seedling Propagation Engineering Research Center, Haikou Experimental Station Chinese Academy of Tropical Agricultural Sciences Haikou Hainan China
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Saito M, Momiki R, Ebine K, Yoshitake Y, Nishihama R, Miyakawa T, Nakano T, Mitsuda N, Araki T, Kohchi T, Yamaoka S. A bHLH heterodimer regulates germ cell differentiation in land plant gametophytes. Curr Biol 2023; 33:4980-4987.e6. [PMID: 37776860 DOI: 10.1016/j.cub.2023.09.020] [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: 06/03/2023] [Revised: 08/20/2023] [Accepted: 09/07/2023] [Indexed: 10/02/2023]
Abstract
Land plants are a monophyletic group of photosynthetic eukaryotes that diverged from streptophyte algae about 470 million years ago. During both the alternating haploid and diploid stages of the life cycle, land plants form multicellular bodies.1,2,3,4 The haploid multicellular body (gametophyte) produces progenitor cells that give rise to gametes and the reproductive organs.5,6,7,8 In the liverwort Marchantia polymorpha, differentiation of the initial cells of gamete-producing organs (gametangia) from the gametophyte is regulated by MpBONOBO (MpBNB), a member of the basic helix-loop-helix (bHLH) transcription factor subfamily VIIIa. In Arabidopsis thaliana, specification of generative cells in developing male gametophytes (pollen) requires redundant action of BNB1 and BNB2.9 Subfamily XI bHLHs, such as LOTUS JAPONICUS ROOTHAIRLESS LIKE1 (LRL1)/DEFECTIVE REGION OF POLLEN1 (DROP1) and LRL2/DROP2 in A. thaliana and the single LRL/DROP protein MpLRL in M. polymorpha, are the evolutionarily conserved regulators of rooting system development.10 Although the role of LRL1/DROP1 and LRL2/DROP2 in gametogenesis remains unclear, their loss leads to the formation of abnormal pollen devoid of sperm cells.11 Here, we show that BNBs and LRL/DROPs co-localize to gametophytic cell nuclei and form heterodimers. LRL1/DROP1 and LRL2/DROP2 act redundantly to regulate BNB expression for generative cell specification in A. thaliana after asymmetric division of the haploid microspore. MpLRL is required for differentiation of MpBNB-expressing gametangium initial cells in M. polymorpha gametophytes. Our findings suggest that broadly expressed LRL/DROP stabilizes BNB expression, leading to the formation of an evolutionarily conserved bHLH heterodimer, which regulates germ cell differentiation in the haploid gametophyte of land plants.
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Affiliation(s)
- Misaki Saito
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ryosuke Momiki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Kazuo Ebine
- National Institute for Basic Biology (NIBB), Okazaki, Aichi 444-8585, Japan; The Graduate University for Advanced Studies, SOKENDAI, Okazaki, Aichi 444-8585, Japan
| | | | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan; Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Takuya Miyakawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Takeshi Nakano
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Nobutaka Mitsuda
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan
| | - Takashi Araki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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3
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Rauf A, Khatab H, Borg M, Twell D. Genetic control of generative cell shape by DUO1 in Arabidopsis. PLANT REPRODUCTION 2023:10.1007/s00497-023-00462-x. [PMID: 37022491 PMCID: PMC10363056 DOI: 10.1007/s00497-023-00462-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/22/2023] [Indexed: 06/19/2023]
Abstract
The main features of generative cell morphogenesis, formation of a cytoplasmic projection and elongation of the GC body, operate through independent genetic pathways. Male gametogenesis in developing angiosperm pollen involves distinctive changes in cell morphogenesis. Re-shaping and elongation of the generative cell (GC) are linked to the formation of a GC cytoplasmic projection connected to the vegetative cell nucleus. Although genetic control of GC morphogenesis is unknown, we suspected the involvement of the germline-specific MYB transcription factor DUO POLLEN1 (DUO1). We used light and fluorescence microscopy to examine male germline development in pollen of wild-type Arabidopsis and in four allelic duo1 mutants expressing introduced cell markers. Our analysis shows that the undivided GC in duo1 pollen forms a cytoplasmic projection, but the cell body fails to elongate. In contrast GCs of cyclin-dependent kinase function mutants, which fail to divide like duo1 mutants, achieve normal morphogenesis. We conclude that DUO1 has an essential role in the elongation of the GC, but DUO1-independent pathways control the development of the GC cytoplasmic projection. The two main features of GC morphogenesis therefore operate through independently regulated genetic pathways.
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Affiliation(s)
- Abdur Rauf
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
- Department of Botany, Garden Campus, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Hoda Khatab
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
- Department of Botany, Faculty of Science, University of Omar Al-Mukhtar, Al-Baida, Libya
| | - Michael Borg
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen, Max-Planck-Ring 5, 72076, Tübingen, Germany
| | - David Twell
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK.
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Arias LA, D'Ippolito S, Frik J, Amigo NL, Marchetti F, Casalongué CA, Pagnussat GC, Fiol DF. The DC1 Domain Protein BINUCLEATE POLLEN is Required for POLLEN Development in Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2023; 63:1994-2007. [PMID: 36001044 DOI: 10.1093/pcp/pcac122] [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: 05/12/2022] [Revised: 08/19/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023]
Abstract
The development of the male gametophyte is a tightly regulated process that requires the precise control of cell division and gene expression. A relevant aspect to understand the events underlying pollen development regulation constitutes the identification and characterization of the genes required for this process. In this work, we showed that the DC1 domain protein BINUCLEATE POLLEN (BNP) is essential for pollen development and germination. Pollen grains carrying a defective BNP alleles failed to complete mitosis II and exhibited impaired pollen germination. By yeast two-hybrid analysis and bimolecular fluorescence complementation assays, we identified a set of BNP-interacting proteins. Among confirmed interactors, we found the NAC family transcriptional regulators Vascular Plant One-Zinc Finger 1 (VOZ1) and VOZ2. VOZ1 localization changes during pollen development, moving to the vegetative nucleus at the tricellular stage. We observed that this relocalization requires BNP; in the absence of BNP in pollen from bnp/BNP plants, VOZ1 nuclear localization is impaired. As the voz1voz2 double mutants showed the same developmental defect observed in bnp pollen grains, we propose that BNP requirement to complete microgametogenesis could be linked to its interaction with VOZ1/2 proteins. BNP could have the role of a scaffold protein, recruiting VOZ1/2 to the endosomal system into assemblies that are required for their further translocation to the nucleus, where they act as transcriptional regulators.
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Affiliation(s)
- Leonardo A Arias
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
| | - Sebastián D'Ippolito
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
| | - Jésica Frik
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
| | - Natalia L Amigo
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
| | - Fernanda Marchetti
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
| | - Claudia A Casalongué
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
| | - Gabriela C Pagnussat
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
| | - Diego F Fiol
- Instituto de investigaciones Biológicas IIB-CONICET - Universidad Nacional de Mar del Plata, Funes 3250, Mar del Plata, Buenos Aires 7600, Argentina
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5
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Abstract
The gametophyte represents the sexual phase in the alternation of generations in plants; the other, nonsexual phase is the sporophyte. Here, we review the evolutionary origins of the male gametophyte among land plants and, in particular, its ontogenesis in flowering plants. The highly reduced male gametophyte of angiosperm plants is a two- or three-celled pollen grain. Its task is the production of two male gametes and their transport to the female gametophyte, the embryo sac, where double fertilization takes place. We describe two phases of pollen ontogenesis-a developmental phase leading to the differentiation of the male germline and the formation of a mature pollen grain and a functional phase representing the pollen tube growth, beginning with the landing of the pollen grain on the stigma and ending with double fertilization. We highlight recent advances in the complex regulatory mechanisms involved, including posttranscriptional regulation and transcript storage, intracellular metabolic signaling, pollen cell wall structure and synthesis, protein secretion, and phased cell-cell communication within the reproductive tissues.
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Affiliation(s)
- Said Hafidh
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic; ,
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 165 02 Prague 6, Czech Republic; ,
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6
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Zhou L, Vejlupkova Z, Warman C, Fowler JE. A Maize Male Gametophyte-Specific Gene Encodes ZmLARP6c1, a Potential RNA-Binding Protein Required for Competitive Pollen Tube Growth. FRONTIERS IN PLANT SCIENCE 2021; 12:635244. [PMID: 33719310 PMCID: PMC7947365 DOI: 10.3389/fpls.2021.635244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/08/2021] [Indexed: 06/12/2023]
Abstract
Members of the La-related protein family (LARPs) contain a conserved La module, which has been associated with RNA-binding activity. Expression of the maize gene GRMZM2G323499/Zm00001d018613, a member of the LARP family, is highly specific to pollen, based on both transcriptomic and proteomic assays. This suggests a pollen-specific RNA regulatory function for the protein, designated ZmLARP6c1 based on sequence similarity to the LARP6 subfamily in Arabidopsis. To test this hypothesis, a Ds-GFP transposable element insertion in the ZmLarp6c1 gene (tdsgR82C05) was obtained from the Dooner/Du mutant collection. Sequencing confirmed that the Ds-GFP insertion is in an exon, and thus likely interferes with ZmLARP6c1 function. Tracking inheritance of the insertion via its endosperm-expressed GFP indicated that the mutation was associated with reduced transmission from a heterozygous plant when crossed as a male (ranging from 0.5 to 26.5% transmission), but not as a female. Furthermore, this transmission defect was significantly alleviated when less pollen was applied to the silk, reducing competition between mutant and wild-type pollen. Pollen grain diameter measurements and nuclei counts showed no significant differences between wild-type and mutant pollen. However, in vitro, mutant pollen tubes were significantly shorter than those from sibling wild-type plants, and also displayed altered germination dynamics. These results are consistent with the idea that ZmLARP6c1 provides an important regulatory function during the highly competitive progamic phase of male gametophyte development following arrival of the pollen grain on the silk. The conditional, competitive nature of the Zmlarp6c1::Ds male sterility phenotype (i.e., reduced ability to produce progeny seed) points toward new possibilities for genetic control of parentage in crop production.
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Affiliation(s)
- Lian Zhou
- Maize Research Institute, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
| | - Zuzana Vejlupkova
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Cedar Warman
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - John E Fowler
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
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7
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Schattner S, Schattner J, Munder F, Höppe E, Walter WJ. A Tug-of-War Model Explains the Saltatory Sperm Cell Movement in Arabidopsis thaliana Pollen Tubes by Kinesins With Calponin Homology Domain. FRONTIERS IN PLANT SCIENCE 2021; 11:601282. [PMID: 33664751 PMCID: PMC7921805 DOI: 10.3389/fpls.2020.601282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/28/2020] [Indexed: 05/16/2023]
Abstract
Upon pollination, two sperm cells are transported inside the growing pollen tube toward the apex. One sperm cell fertilizes the egg cell to form the zygote, while the other fuses with the two polar nuclei to form the triploid endosperm. In Arabidopsis thaliana, the transport of the two sperm cells is characterized by sequential forward and backward movements with intermediate pauses. Until now, it is under debate which components of the plant cytoskeleton govern this mechanism. The sperm cells are interconnected and linked to the vegetative nucleus via a cytoplasmic projection, thus forming the male germ unit. This led to the common hypothesis that the vegetative nucleus is actively transported via myosin motors along actin cables while pulling along the sperm cells as passive cargo. In this study, however, we show that upon occasional germ unit disassembly, the sperm cells are transported independently and still follow the same bidirectional movement pattern. Moreover, we found that the net movement of sperm cells results from a combination of both longer and faster runs toward the pollen tube apex. We propose that the observed saltatory movement can be explained by the function of kinesins with calponin homology domain (KCH). This subgroup of the kinesin-14 family actively links actin filaments and microtubules. Based on KCH's specific properties derived from in vitro experiments, we built a tug-of-war model that could reproduce the characteristic sperm cell movement in pollen tubes.
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Affiliation(s)
- Saskia Schattner
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Jan Schattner
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Fabian Munder
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Eva Höppe
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Wilhelm J. Walter
- Department of Biology, Institute for Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
- Department Medicine, Health and Medical University Potsdam, Potsdam, Germany
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8
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Pereira PA, Boavida LC, Santos MR, Becker JD. AtNOT1 is required for gametophyte development in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1289-1303. [PMID: 32369648 DOI: 10.1111/tpj.14801] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 04/15/2020] [Accepted: 04/22/2020] [Indexed: 06/11/2023]
Abstract
In flowering plants, pollen development is under a dynamic and well-orchestrated transcriptional control, characterized by an early phase with high transcript diversity and a late post-mitotic phase skewed to a cell-type-specific transcriptome. Such transcriptional changes require a balance between synthesis and degradation of mRNA transcripts, the latter being initiated by deadenylation. The CCR4-NOT complex is the main evolutionary conserved deadenylase complex in eukaryotes, and its function is essential during germline specification in animals. We hypothesized that the CCR4-NOT complex might play a central role in mRNA turnover during microgametogenesis in Arabidopsis. Disruption of NOT1 gene, which encodes the scaffold protein of the CCR4-NOT complex, showed abnormal seed set. Genetic analysis failed to recover homozygous progeny, and reciprocal crosses confirmed reduced transmission through the male and female gametophytes. Concordantly, not1 embryo sacs showed delayed development and defects in embryogenesis. not1 pollen grains exhibited abnormal male germ unit configurations and failed to germinate. Transcriptome analysis of pollen from not1/+ mutants revealed that lack of NOT1 leads to an extensive transcriptional deregulation during microgametogenesis. Therefore, our work establishes NOT1 as an important player during gametophyte development in Arabidopsis.
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Affiliation(s)
- Patrícia A Pereira
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras, 2780-156, Portugal
| | - Leonor C Boavida
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras, 2780-156, Portugal
| | - Mário R Santos
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras, 2780-156, Portugal
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, Oeiras, 2780-156, Portugal
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Oeiras, 2780-157, Portugal
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9
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Galindo-Trigo S, Grand TM, Voigt CA, Smith LM. A malectin domain kinesin functions in pollen and seed development in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1828-1841. [PMID: 31950166 PMCID: PMC7094084 DOI: 10.1093/jxb/eraa023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 01/13/2020] [Indexed: 05/25/2023]
Abstract
The kinesin family is greatly expanded in plants compared with animals and, with more than a third up-regulated in expression during cell division, it has been suggested that this expansion facilitated complex plant-specific cytoskeletal rearrangements. The cell cycle-regulated kinesins include two with an N-terminal malectin domain, a protein domain that has been shown to bind polysaccharides and peptides when found extracellularly in receptor-like kinases. Although malectin domain kinesins are evolutionarily deep rooted, their function in plants remains unclear. Here we show that loss of MALECTIN DOMAIN KINESIN 2 (MDKIN2) results in stochastic developmental defects in pollen, embryo, and endosperm. High rates of seed abnormalities and abortion occur in mdkin2 mutants through a partial maternal effect. No additive effect or additional developmental defects were noted in mdkin1 mdkin2 double mutants. MDKIN2 is expressed in regions of cell division throughout the plant. Subcellular localization of MDKIN2 indicates a role in cell division, with a possible secondary function in the nuclei. Our results reveal a non-essential but important role for a malectin domain kinesin during development in plants.
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Affiliation(s)
- Sergio Galindo-Trigo
- Department of Animal and Plant Sciences and The Plant Production and Protection (P3) Centre, University of Sheffield, Western Bank, Sheffield, UK
| | - Thomas M Grand
- Department of Animal and Plant Sciences and The Plant Production and Protection (P3) Centre, University of Sheffield, Western Bank, Sheffield, UK
| | - Christian A Voigt
- Department of Animal and Plant Sciences and The Plant Production and Protection (P3) Centre, University of Sheffield, Western Bank, Sheffield, UK
| | - Lisa M Smith
- Department of Animal and Plant Sciences and The Plant Production and Protection (P3) Centre, University of Sheffield, Western Bank, Sheffield, UK
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10
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Long YP, Xie DJ, Zhao YY, Shi DQ, Yang WC. BICELLULAR POLLEN 1 is a modulator of DNA replication and pollen development in Arabidopsis. THE NEW PHYTOLOGIST 2019; 222:588-603. [PMID: 30484867 DOI: 10.1111/nph.15610] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
During male gametogenesis in Arabidopsis, the haploid microspore undergoes an asymmetric division to produce a vegetative and a generative cell, the latter of which continues to divide symmetrically to form two sperms. This simple system couples cell cycle with cell fate specification. Here we addressed the role of DNA replication in male gametogenesis using a mutant bicellular pollen 1 (bice1), which produces bicellular, rather than tricellular, pollen grains as in the wild-type plant at anthesis. The mutation prolonged DNA synthesis of the generative cell, which resulted in c. 40% of pollen grains arrested at the two-nucleate stage. The extended S phase did not impact the cell fate of the generative cell as shown by cell-specific markers. BICE1 encodes a plant homolog of human D123 protein that is required for G1 progression, but the underlying mechanism is unknown. Here we showed that BICE1 interacts with MCM4 and MCM7 of the pre-replication complex. Consistently, double mutations in BICE1 and MCM4, or MCM7, also led to bicellular pollen and condensed chromosomes. These suggest that BICE1 plays a role in modulating DNA replication via interaction with MCM4 and MCM7.
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Affiliation(s)
- Yan-Ping Long
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, East Lincui Road, Beijing, 100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
| | - Dong-Jiang Xie
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, East Lincui Road, Beijing, 100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
| | - Yan-Yan Zhao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, East Lincui Road, Beijing, 100101, China
| | - Dong-Qiao Shi
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, East Lincui Road, Beijing, 100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, East Lincui Road, Beijing, 100101, China
- College of Advanced Agricultural Sciences, University of the Chinese Academy of Sciences, Yuquan Road, Beijing, 100049, China
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11
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Huang X, Peng X, Xie F, Mao W, Chen H, Sun MX. The stereotyped positioning of the generative cell associated with vacuole dynamics is not required for male gametogenesis in rice pollen. THE NEW PHYTOLOGIST 2018; 218:463-469. [PMID: 29424430 DOI: 10.1111/nph.15038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 01/14/2018] [Indexed: 06/08/2023]
Abstract
During male gametogenesis in cereals, the generative cell undergoes a positioning process that parallels the dynamics of the central vacuole, which is believed to be associated with generative cell movement in the male gametophyte. However, the impact of the generative cell positioning and the central vacuole dynamics on male gametogenesis has remained poorly understood. Here, we report that OsGCD1 (GAMETE CELLS DEFECTIVE1) dysfunction influenced pollen development and disrupted pollen germination. Loss of function of OsGCD1 altered the central vacuole dynamics and the generative cell was mispositioned. Nevertheless, twin sperm cells were generated normally, indicating that gametogenesis does not rely on positional information as long as a generative cell is produced. The normal vacuole dynamics seems necessary only for pollen maturation and germination. Our findings also indicate that osgcd1 mutation resulted in rice male sterility in which pollen has full cell viability and generated normal gametes, but lacks the potential to germinate.
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Affiliation(s)
- Xiaorong Huang
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Xiongbo Peng
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Fei Xie
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Wanying Mao
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Hong Chen
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
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12
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Yamaoka S, Nishihama R, Yoshitake Y, Ishida S, Inoue K, Saito M, Okahashi K, Bao H, Nishida H, Yamaguchi K, Shigenobu S, Ishizaki K, Yamato KT, Kohchi T. Generative Cell Specification Requires Transcription Factors Evolutionarily Conserved in Land Plants. Curr Biol 2018; 28:479-486.e5. [PMID: 29395928 DOI: 10.1016/j.cub.2017.12.053] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/11/2017] [Accepted: 12/22/2017] [Indexed: 12/23/2022]
Abstract
Land plants differentiate germ cells in the haploid gametophyte. In flowering plants, a generative cell is specified as a precursor that subsequently divides into two sperm cells in the developing male gametophyte, pollen. Generative cell specification requires cell-cycle control and microtubule-dependent nuclear relocation (reviewed in [1-3]). However, the generative cell fate determinant and its evolutionary origin are still unknown. In bryophytes, gametophytes produce eggs and sperm in multicellular reproductive organs called archegonia and antheridia, respectively, or collectively called gametangia. Given the monophyletic origin of land plants [4-6], evolutionarily conserved mechanisms may play key roles in these diverse reproductive processes. Here, we showed that a single member of the subfamily VIIIa of basic helix-loop-helix (bHLH) transcription factors in the liverwort Marchantia polymorpha primarily accumulated in the initial cells and controlled their development into gametangia. We then demonstrated that an Arabidopsis thaliana VIIIa bHLH transiently accumulated in the smaller daughter cell after an asymmetric division of the meiosis-derived microspore and was required for generative cell specification redundantly with its paralog. Furthermore, these A. thaliana VIIIa bHLHs were functionally replaceable by the M. polymorpha VIIIa bHLH. These findings suggest the VIIIa bHLH proteins as core regulators for reproductive development, including germ cell differentiation, since an early stage of land plant evolution.
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Affiliation(s)
- Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | | | - Sakiko Ishida
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Keisuke Inoue
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Misaki Saito
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Keitaro Okahashi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Haonan Bao
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Hiroyuki Nishida
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Katsushi Yamaguchi
- Functional Genomics Facility, National Institute for Basic Biology (NIBB), Okazaki, Aichi 444-8585, Japan
| | - Shuji Shigenobu
- Functional Genomics Facility, National Institute for Basic Biology (NIBB), Okazaki, Aichi 444-8585, Japan
| | | | - Katsuyuki T Yamato
- Faculty of Biology-Oriented Science and Technology, Kindai University, Kinokawa, Wakayama 649-6493, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
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D'Ippólito S, Arias LA, Casalongué CA, Pagnussat GC, Fiol DF. The DC1-domain protein VACUOLELESS GAMETOPHYTES is essential for development of female and male gametophytes in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 90:261-275. [PMID: 28107777 DOI: 10.1111/tpj.13486] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 01/06/2017] [Accepted: 01/11/2017] [Indexed: 06/06/2023]
Abstract
In this work we identified VACUOLELESS GAMETOPHYTES (VLG) as a DC1 domain-containing protein present in the endomembrane system and essential for development of both female and male gametophytes. VLG was originally annotated as a gene coding for a protein of unknown function containing DC1 domains. DC1 domains are cysteine- and histidine-rich zinc finger domains found exclusively in the plant kingdom that have been named on the basis of similarity with the C1 domain present in protein kinase C (PKC). In Arabidopsis, both male and female gametophytes are characterized by the formation of a large vacuole early in development; this is absent in vlg mutant plants. As a consequence, development is arrested in embryo sacs and pollen grains at the first mitotic division. VLG is specifically located in multivesicular bodies or pre-vacuolar compartments, and our results suggest that vesicular fusion is affected in the mutants, disrupting vacuole formation. Supporting this idea, AtPVA12 - a member of the SNARE vesicle-associated protein family and previously related to a sterol-binding protein, was identified as a VLG interactor. A role for VLG is proposed mediating vesicular fusion in plants as part of the sterol trafficking machinery required for vacuole biogenesis in plants.
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Affiliation(s)
- Sebastián D'Ippólito
- Instituto de Investigaciones Biológicas, IIB-CONICET-Universidad Nacional de Mar del Plata, Funes 3250 Cuarto Nivel, 7600, Mar del Plata, Argentina
| | - Leonardo Agustín Arias
- Instituto de Investigaciones Biológicas, IIB-CONICET-Universidad Nacional de Mar del Plata, Funes 3250 Cuarto Nivel, 7600, Mar del Plata, Argentina
| | - Claudia Anahí Casalongué
- Instituto de Investigaciones Biológicas, IIB-CONICET-Universidad Nacional de Mar del Plata, Funes 3250 Cuarto Nivel, 7600, Mar del Plata, Argentina
| | - Gabriela Carolina Pagnussat
- Instituto de Investigaciones Biológicas, IIB-CONICET-Universidad Nacional de Mar del Plata, Funes 3250 Cuarto Nivel, 7600, Mar del Plata, Argentina
| | - Diego Fernando Fiol
- Instituto de Investigaciones Biológicas, IIB-CONICET-Universidad Nacional de Mar del Plata, Funes 3250 Cuarto Nivel, 7600, Mar del Plata, Argentina
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14
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Twell D, Brownfield L. Analysis of Fluorescent Reporter Activity in the Male Germline During Pollen Development by Confocal Microscopy. Methods Mol Biol 2017; 1669:67-75. [PMID: 28936650 DOI: 10.1007/978-1-4939-7286-9_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The male germline of flowering plants develops within the vegetative cell of the male gametophyte (pollen). The germline is established by asymmetric division of the microspore to form the generative cell. Mitotic division of the generative cell then produces the two sperm cells required for double fertilization. These differentiate to produce the proteins required for gamete attachment and fusion. An important aspect of understanding germline development is the characterization of germline gene expression. Here, we describe the use of a fluorescent reporter to study germline gene expression in developing pollen to assess the timing and specificity of expression.
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Affiliation(s)
- David Twell
- Department of Genetics, University of Leicester, Leicester, UK
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15
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Zhou X, Groves NR, Meier I. SUN anchors pollen WIP-WIT complexes at the vegetative nuclear envelope and is necessary for pollen tube targeting and fertility. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:7299-307. [PMID: 26409047 PMCID: PMC4765795 DOI: 10.1093/jxb/erv425] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
LINC (linker of nucleoskeleton and cytoskeleton) complexes play an essential role in nuclear migration by connecting the nucleus to the cytoskeleton and/or motor proteins. Plant LINC complexes have recently been identified in Arabidopsis thaliana, with the inner nuclear membrane SUN and outer nuclear membrane WIP proteins comprising the first identified complex. A recent study identified a nuclear movement defect in Arabidopsis pollen vegetative nuclei linked to the outer nuclear envelope WIP and WIT proteins. However, the role that SUN proteins may play in pollen nuclear migration has yet to be addressed. To explore this question, a SUN2 lumenal domain that was targeted to the ER specifically in pollen was over-expressed. It is shown that the ER-targeted SUN2 lumenal domain was able to displace WIP and WIT proteins from the pollen vegetative nuclear envelope. Expression of this dominant-negative transgene led to impaired VN mobility, impaired pollen tube guidance, and defective pollen tube reception. The observed pollen defects are similar to phenotypes observed in a wip1-1 wip2-1 wip3-1 wit1-1 wit2-1 mutant. It is also shown that these defects were dependent on the KASH-binding function of the SUN2 lumenal domain. These data support a model where LINC complexes formed by SUN, WIP, and WIT at the VNE are responsible for VN migration and suggest an important function of SUN, WIP, and WIT in pollen tube guidance and reception.
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Affiliation(s)
- Xiao Zhou
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Norman Reid Groves
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Iris Meier
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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16
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Takatsuka H, Umeda-Hara C, Umeda M. Cyclin-dependent kinase-activating kinases CDKD;1 and CDKD;3 are essential for preserving mitotic activity in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:1004-1017. [PMID: 25942995 DOI: 10.1111/tpj.12872] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 04/14/2015] [Accepted: 04/24/2015] [Indexed: 05/23/2023]
Abstract
For the full activation of cyclin-dependent kinases (CDKs), not only cyclin binding but also CDK phosphorylation is required. This activating phosphorylation is mediated by CDK-activating kinases (CAKs). Arabidopsis has four genes showing similarity to vertebrate-type CAKs, three CDKDs (CDKD;1-CDKD;3) and one CDKF (CDKF;1). We previously found that the cdkf;1 mutant is defective in post-embryonic development, even though the kinase activities of core CDKs remain unchanged relative to the wild type. This raised a question about the involvement of CDKDs in CDK activation in planta. Here we report that the cdkd;1 cdkd;3 double mutant showed gametophytic lethality. Most cdkd;1-1 cdkd;3-1 pollen grains were defective in pollen mitosis I and II, producing one-cell or two-cell pollen grains that lacked fertilization ability. We also found that the double knock-out of CDKD;1 and CDKD;3 caused arrest and/or delay in the progression of female gametogenesis at multiple steps. Our genetic analyses revealed that the functions of CDKF;1 and CDKD;1 or CDKD;3 do not overlap, either during gametophyte and embryo development or in post-embryonic development. Consistent with these analyses, CDKF;1 expression in the cdkd;1-1 cdkd;3-1 mutant could not rescue the gametophytic lethality. These results suggest that, in Arabidopsis, CDKD;1 and CDKD;3 function as CAKs controlling mitosis, whereas CDKF;1 plays a distinct role, mainly in post-embryonic development. We propose that CDKD;1 and CDKD;3 phosphorylate and activate all core CDKs, CDKA, CDKB1 and CDKB2, thereby governing cell cycle progression throughout plant development.
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Affiliation(s)
- Hirotomo Takatsuka
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Chikage Umeda-Hara
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
| | - Masaaki Umeda
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
- JST, CREST, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan
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17
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Kim MJ, Kim M, Lee MR, Park SK, Kim J. LATERAL ORGAN BOUNDARIES DOMAIN (LBD)10 interacts with SIDECAR POLLEN/LBD27 to control pollen development in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:794-809. [PMID: 25611322 DOI: 10.1111/tpj.12767] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 12/30/2014] [Accepted: 01/08/2015] [Indexed: 05/10/2023]
Abstract
During male gametophyte development in Arabidopsis thaliana, the microspores undergo an asymmetric division to produce a vegetative cell and a generative cell, which undergoes a second division to give rise to two sperm cells. SIDECAR POLLEN/LATERAL ORGAN BOUNDARIES DOMAIN (LBD) 27 plays a key role in the asymmetric division of microspores. Here we provide molecular genetic evidence that a combinatorial role of LBD10 with LBD27 is crucial for male gametophyte development in Arabidopsis. Expression analysis, genetic transmission and pollen viability assays, and pollen development analysis demonstrated that LBD10 plays a role in the male gametophyte function primarily at germ cell mitosis. In the mature pollen of lbd10 and lbd10 expressing a dominant negative version of LBD10, LBD10:SRDX, aberrant microspores such as bicellular and smaller tricellular pollen appeared at a ratio of 10-15% with a correspondingly decreased ratio of normal tricellular pollen, whereas in lbd27 mutants, 70% of the pollen was aborted. All pollen in the lbd10 lbd27 double mutants was aborted and severely shrivelled compared with that of the single mutants, indicating that LBD10 and LBD27 are essential for pollen development. Gene expression and subcellular localization analyses of LBD10:GFP and LBD27:RFP during pollen development indicated that posttranscriptional and/or posttranslational controls are involved in differential accumulation and subcellular localization of LBD10 and LBD27 during pollen development, which may contribute in part to combinatorial and distinct roles of LBD10 with LBD27 in microspore development. In addition, we showed that LBD10 and LBD27 interact to form a heterodimer for nuclear localization.
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Affiliation(s)
- Min-Jung Kim
- Department of Plant Biotechnology, Chonnam National University, Gwangju, 500-757, Korea
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18
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Vogler F, Konrad SSA, Sprunck S. Knockin' on pollen's door: live cell imaging of early polarization events in germinating Arabidopsis pollen. FRONTIERS IN PLANT SCIENCE 2015; 6:246. [PMID: 25954283 PMCID: PMC4404733 DOI: 10.3389/fpls.2015.00246] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/27/2015] [Indexed: 05/20/2023]
Abstract
Pollen tubes are an excellent system for studying the cellular dynamics and complex signaling pathways that coordinate polarized tip growth. Although several signaling mechanisms acting in the tip-growing pollen tube have been described, our knowledge on the subcellular and molecular events during pollen germination and growth site selection at the pollen plasma membrane is rather scarce. To simultaneously track germinating pollen from up to 12 genetically different plants we developed an inexpensive and easy mounting technique, suitable for every standard microscope setup. We performed high magnification live-cell imaging during Arabidopsis pollen activation, germination, and the establishment of pollen tube tip growth by using fluorescent marker lines labeling either the pollen cytoplasm, vesicles, the actin cytoskeleton or the sperm cell nuclei and membranes. Our studies revealed distinctive vesicle and F-actin polarization during pollen activation and characteristic growth kinetics during pollen germination and pollen tube formation. Initially, the germinating Arabidopsis pollen tube grows slowly and forms a uniform roundish bulge, followed by a transition phase with vesicles heavily accumulating at the growth site before switching to rapid tip growth. Furthermore, we found the two sperm cells to be transported into the pollen tube after the phase of rapid tip growth has been initiated. The method presented here is suitable to quantitatively study subcellular events during Arabidopsis pollen germination and growth, and for the detailed analysis of pollen mutants with respect to pollen polarization, bulging, or growth site selection at the pollen plasma membrane.
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Affiliation(s)
- Frank Vogler
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum RegensburgUniversity of Regensburg, Regensburg Germany
| | - Sebastian S. A. Konrad
- Faculty of Biology, Institute of Genetics, Ludwig-Maximilians-University of MunichMartinsried, Germany
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum RegensburgUniversity of Regensburg, Regensburg Germany
- *Correspondence: Stefanie Sprunck, Department of Cell Biology and Plant Biochemistry, University of Regensburg, Universitaetsstrasse 31, 93053 Regensburg, Germany
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19
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Liu M, Xu R, Merrill C, Hong L, Von Lanken C, Hunt AG, Li QQ. Integration of developmental and environmental signals via a polyadenylation factor in Arabidopsis. PLoS One 2014; 9:e115779. [PMID: 25546057 PMCID: PMC4278772 DOI: 10.1371/journal.pone.0115779] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 11/28/2014] [Indexed: 11/19/2022] Open
Abstract
The ability to integrate environmental and developmental signals with physiological responses is critical for plant survival. How this integration is done, particularly through posttranscriptional control of gene expression, is poorly understood. Previously, it was found that the 30 kD subunit of Arabidopsis cleavage and polyadenylation specificity factor (AtCPSF30) is a calmodulin-regulated RNA-binding protein. Here we demonstrated that mutant plants (oxt6) deficient in AtCPSF30 possess a novel range of phenotypes--reduced fertility, reduced lateral root formation, and altered sensitivities to oxidative stress and a number of plant hormones (auxin, cytokinin, gibberellic acid, and ACC). While the wild-type AtCPSF30 (C30G) was able to restore normal growth and responses, a mutant AtCPSF30 protein incapable of interacting with calmodulin (C30GM) could only restore wild-type fertility and responses to oxidative stress and ACC. Thus, the interaction with calmodulin is important for part of AtCPSF30 functions in the plant. Global poly(A) site analysis showed that the C30G and C30GM proteins can restore wild-type poly(A) site choice to the oxt6 mutant. Genes associated with hormone metabolism and auxin responses are also affected by the oxt6 mutation. Moreover, 19 genes that are linked with calmodulin-dependent CPSF30 functions, were identified through genome-wide expression analysis. These data, in conjunction with previous results from the analysis of the oxt6 mutant, indicate that the polyadenylation factor AtCPSF30 is a regulatory hub where different signaling cues are transduced, presumably via differential mRNA 3' end formation or alternative polyadenylation, into specified phenotypic outcomes. Our results suggest a novel function of a polyadenylation factor in environmental and developmental signal integration.
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Affiliation(s)
- Man Liu
- Department of Biology, Miami University, Oxford, OH 45045, United States of America
| | - Ruqiang Xu
- Department of Biology, Miami University, Oxford, OH 45045, United States of America
| | - Carrie Merrill
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40506, United States of America
| | - Liwei Hong
- Key Laboratory of the Ministry of Education on Costal Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China
| | - Carol Von Lanken
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40506, United States of America
| | - Arthur G. Hunt
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40506, United States of America
| | - Qingshun Q. Li
- Department of Biology, Miami University, Oxford, OH 45045, United States of America
- Key Laboratory of the Ministry of Education on Costal Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian 361102, China
- Rice Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian, 350003, China
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20
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Evolutionarily conserved mechanisms of male germline development in flowering plants and animals. Biochem Soc Trans 2014; 42:377-82. [DOI: 10.1042/bst20130261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sexual reproduction is the main reproductive strategy of the overwhelming majority of eukaryotes. This suggests that the last eukaryotic common ancestor was able to reproduce sexually. Sexual reproduction reflects the ability to perform meiosis, and ultimately generating gametes, which are cells that carry recombined half sets of the parental genome and are able to fertilize. These functions have been allocated to a highly specialized cell lineage: the germline. Given its significant evolutionary conservation, it is to be expected that the germline programme shares common molecular bases across extremely divergent eukaryotic species. In the present review, we aim to identify the unifying principles of male germline establishment and development by comparing two very disparate kingdoms: plants and animals. We argue that male meiosis defines two temporally regulated gene expression programmes: the first is required for meiotic commitment, and the second is required for the acquisition of fertilizing ability. Small RNA pathways are a further key communality, ultimately ensuring the epigenetic stability of the information conveyed by the male germline.
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21
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The Arabidopsis Plant Intracellular Ras-group LRR (PIRL) Family and the Value of Reverse Genetic Analysis for Identifying Genes that Function in Gametophyte Development. PLANTS 2013; 2:507-20. [PMID: 27137390 PMCID: PMC4844374 DOI: 10.3390/plants2030507] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/02/2013] [Accepted: 07/24/2013] [Indexed: 12/31/2022]
Abstract
Arabidopsis thaliana has proven a powerful system for developmental genetics, but identification of gametophytic genes with developmental mutants can be complicated by factors such as gametophyte-lethality, functional redundancy, or poor penetrance. These issues are exemplified by the Plant Intracellular Ras-group LRR (PIRL) genes, a family of nine genes encoding a class of leucine-rich repeat proteins structurally related to animal and fungal LRR proteins involved in developmental signaling. Previous analysis of T-DNA insertion mutants showed that two of these genes, PIRL1 and PIRL9, have an essential function in pollen formation but are functionally redundant. Here, we present evidence implicating three more PIRLs in gametophyte development. Scanning electron microscopy revealed that disruption of either PIRL2 or PIRL3 results in a low frequency of pollen morphological abnormalities. In addition, molecular analysis of putative pirl6 insertion mutants indicated that knockout alleles of this gene are not represented in current Arabidopsis mutant populations, suggesting gametophyte lethality may hinder mutant recovery. Consistent with this, available microarray and RNA-seq data have documented strongest PIRL6 expression in developing pollen. Taken together, these results now implicate five PIRLs in gametophyte development. Systematic reverse genetic analysis of this novel LRR family has therefore identified gametophytically active genes that otherwise would likely be missed by forward genetic screens.
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22
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Dubas E, Wedzony M, Custers J, Kieft H, van Lammeren AAM. Gametophytic development of Brassica napus pollen in vitroenables examination of cytoskeleton and nuclear movements. PROTOPLASMA 2012; 249:369-77. [PMID: 21611884 PMCID: PMC3305877 DOI: 10.1007/s00709-011-0287-0] [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: 03/11/2011] [Accepted: 05/11/2011] [Indexed: 05/08/2023]
Abstract
Isolated microspores and pollen suspension of Brassica napus "Topas" cultured in NLN-13 medium at 18°C follow gametophytic pathway and develop into pollen grains closely resembling pollen formed in planta. This culture system complemented with whole-mount immunocytochemical technology and novel confocal laser scanning optical technique enables detailed studies of male gametophyte including asymmetric division, cytoskeleton, and nuclear movements. Microtubular cytoskeleton configurationally changed in successive stages of pollen development. The most prominent role of microtubules (MTs) was observed just before and during nuclear migration at the early and mid-bi-cellular stage. At the early bi-cellular stage, parallel arrangement of cortical and endoplasmic MTs to the long axis of the generative cell (GC) as well as MTs within GC under the plasmalemma bordering vegetative cell (VC) were responsible for GC lens shape. At the beginning of the GC migration, endoplasmic microtubules (EMTs) of the VC radiated from the nuclear envelope. Most cortical and EMTs of the VC were found near the sporoderm. At the same time, pattern of MTs observed in GC was considerably different. Multiple EMTs of the GC, previously parallel aligned, reorganized, and start to surround GC, forming a basket-like structure. These results suggest that EMTs of GC provoke changes in GC shape, its detachment from the sporoderm, and play an important role in GC migration to the vegetative nucleus (VN). During the process of migration of the GC to the VC, multiple and thick bundles of MTs, radiating from the cytoplasm near GC plasma membrane, arranged perpendicular to the narrow end of the GC and organized into a "comet-tail" form. These GC "tail" MTs became shortened and the generative nucleus (GN) took a ball shape. The dynamic changes of MTs accompanied polarized distribution pattern of mitochondria and endoplasmic reticulum. In order to confirm the role of MTs in pollen development, a "whole-mount" immunodetection technique and confocal laser-scanning microscopy was essential.
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Affiliation(s)
- Ewa Dubas
- Laboratory of Plant Cell Biology, Wageningen University, Droevendaalsesteeg 1, Radix building 107, W1 6708 PB, Wageningen, The Netherlands.
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23
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Liu L. Ultrastructural study on dynamics of plastids and mitochondria during microgametogenesis in watermelon. Micron 2012; 43:412-7. [DOI: 10.1016/j.micron.2011.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 10/06/2011] [Accepted: 10/14/2011] [Indexed: 11/16/2022]
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24
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Qin Y, Wysocki RJ, Somogyi A, Feinstein Y, Franco JY, Tsukamoto T, Dunatunga D, Levy C, Smith S, Simpson R, Gang D, Johnson MA, Palanivelu R. Sulfinylated azadecalins act as functional mimics of a pollen germination stimulant in Arabidopsis pistils. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 68:800-15. [PMID: 21801250 PMCID: PMC3225508 DOI: 10.1111/j.1365-313x.2011.04729.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Polarized cell elongation is triggered by small molecule cues during development of diverse organisms. During plant reproduction, pollen interactions with the stigma result in the polar outgrowth of a pollen tube, which delivers sperm cells to the female gametophyte to effect double fertilization. In many plants, pistils stimulate pollen germination. However, in Arabidopsis, the effect of pistils on pollen germination and the pistil factors that stimulate pollen germination remain poorly characterized. Here, we demonstrate that stigma, style, and ovules in Arabidopsis pistils stimulate pollen germination. We isolated an Arabidopsis pistil extract fraction that stimulates Arabidopsis pollen germination, and employed ultra-high resolution electrospray ionization (ESI), Fourier-transform ion cyclotron resonance (FT-ICR) and MS/MS techniques to accurately determine the mass (202.126 Da) of a compound that is specifically present in this pistil extract fraction. Using the molecular formula (C10H19NOS) and tandem mass spectral fragmentation patterns of the m/z (mass to charge ratio) 202.126 ion, we postulated chemical structures, devised protocols, synthesized N-methanesulfinyl 1- and 2-azadecalins that are close structural mimics of the m/z 202.126 ion, and showed that they are sufficient to stimulate Arabidopsis pollen germination in vitro (30 μm stimulated approximately 50% germination) and elicit accession-specific response. Although N-methanesulfinyl 2-azadecalin stimulated pollen germination in three species of Lineage I of Brassicaceae, it did not induce a germination response in Sisymbrium irio (Lineage II of Brassicaceae) and tobacco, indicating that activity of the compound is not random. Our results show that Arabidopsis pistils promote germination by producing azadecalin-like molecules to ensure rapid fertilization by the appropriate pollen.
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Affiliation(s)
- Yuan Qin
- The School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Ronald J Wysocki
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - Arpad Somogyi
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721
| | - Yelena Feinstein
- Arizona Proteomics Consortium, University of Arizona, Tucson, AZ 85721, USA
| | - Jessica Y Franco
- The School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Tatsuya Tsukamoto
- The School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | | | - Clara Levy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, U.S.A
| | - Steven Smith
- The School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ 85721, USA
| | | | - David Gang
- The School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Mark A Johnson
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, U.S.A
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25
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Reňák D, Dupl'áková N, Honys D. Wide-scale screening of T-DNA lines for transcription factor genes affecting male gametophyte development in Arabidopsis. ACTA ACUST UNITED AC 2011; 25:39-60. [PMID: 22101548 DOI: 10.1007/s00497-011-0178-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 11/06/2011] [Indexed: 12/29/2022]
Abstract
Male gametophyte development leading to the formation of a mature pollen grain is precisely controlled at various levels, including transcriptional, post-transcriptional and post-translational, during its whole progression. Transcriptomic studies exploiting genome-wide microarray technologies revealed the uniqueness of pollen transcriptome and the dynamics of early and late successive global gene expression programs. However, the knowledge of transcription regulation is still very limited. In this study, we focused on the identification of pollen-expressed transcription factor (TF) genes involved in the regulation of male gametophyte development. To achieve this, the reverse genetic approach was used. Seventy-four T-DNA insertion lines were screened, representing 49 genes of 21 TF families active in either early or late pollen development. In the screen, ten phenotype categories were distinguished, affecting various structural or functional aspects, including pollen abortion, presence of inclusions, variable pollen grain size, disrupted cell wall structure, cell cycle defects, and male germ unit organization. Thirteen lines were not confirmed to contain the T-DNA insertion. Among 61 confirmed lines, about half (29 lines) showed strong phenotypic changes (i.e., ≥ 25% aberrant pollen) including four lines that produced a remarkably high proportion (70-100%) of disturbed pollen. However, the remaining 32 lines exhibited mild defects or resembled wild-type appearance. There was no significant bias toward any phenotype category among early and late TF genes, nor, interestingly, within individual TF families. Presented results have a potential to serve as a basal information resource for future research on the importance of respective TFs in male gametophyte development.
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Affiliation(s)
- David Reňák
- Laboratory of Pollen Biology, Institute of Experimental Botany ASCR, Rozvojová 263, 165 02 Prague 6, Czech Republic
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26
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Zhang J, Teng C, Liang Y. Programmed cell death may act as a surveillance mechanism to safeguard male gametophyte development in Arabidopsis. Protein Cell 2011; 2:837-44. [PMID: 22058038 DOI: 10.1007/s13238-011-1102-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 09/13/2011] [Indexed: 11/28/2022] Open
Abstract
Programmed cell death (PCD) plays an important role in plant growth and development as well as in stress responses. During male gametophyte development, it has been proposed that PCD may act as a cellular surveillance mechanism to ensure successful progression of male gametogenesis, and this suicide protective machinery is repressed under favorable growth conditions. However, the regulatory mechanism of male gametophyte-specific PCD remains unknown. Here, we report the use of a TdT-mediated dUTP nick-end labeling-based strategy for genetic screening of Arabidopsis mutants that present PCD phenotype during male gametophyte development. By using this approach, we identified 12 mutants, designated as pcd in male gametogenesis (pig). pig mutants are defective at various stages of male gametophyte development, among which nine pig mutants show a microspore-specific PCD phenotype occurring mainly around pollen mitosis I or the bicellular stage. The PIG1 gene was identified by map-based cloning, and was found to be identical to ATAXIA TELANGIECTASIA MUTATED (ATM), a highly conserved gene in eukaryotes and a key regulator of the DNA damage response. Our results suggest that PCD may act as a general mechanism to safeguard the entire process of male gametophyte development.
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Affiliation(s)
- Jian Zhang
- State Key Laboratory of Plant Genomics and National Plant Gene Research Center, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
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27
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Live-cell imaging reveals the dynamics of two sperm cells during double fertilization in Arabidopsis thaliana. Curr Biol 2011; 21:497-502. [PMID: 21396821 DOI: 10.1016/j.cub.2011.02.013] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 02/04/2011] [Accepted: 02/10/2011] [Indexed: 01/11/2023]
Abstract
Flowering plants have evolved a unique reproductive process called double fertilization, whereby two dimorphic female gametes are fertilized by two immotile sperm cells conveyed by the pollen tube. The two sperm cells are arranged in tandem with a leading pollen tube nucleus to form the male germ unit and are placed under the same genetic controls. Genes controlling double fertilization have been identified, but whether each sperm cell is able to fertilize either female gamete is still unclear. The dynamics of individual sperm cells after their release in the female tissue remain largely unknown. In this study, we photolabeled individual isomorphic sperm cells before their release and analyzed their fate during double fertilization in Arabidopsis thaliana. We found that sperm delivery was composed of three steps. Sperm cells were projected together to the boundary between the two female gametes. After a long period of immobility, each sperm cell fused with either female gamete in no particular order, and no preference was observed for either female gamete. Our results suggest that the two sperm cells at the front and back of the male germ unit are functionally equivalent and suggest unexpected cell-cell communications required for sperm cells to coordinate double fertilization of the two female gametes.
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28
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Roy B, Copenhaver GP, von Arnim AG. Fluorescence-tagged transgenic lines reveal genetic defects in pollen growth--application to the eIF3 complex. PLoS One 2011; 6:e17640. [PMID: 21408229 PMCID: PMC3049774 DOI: 10.1371/journal.pone.0017640] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 02/08/2011] [Indexed: 11/25/2022] Open
Abstract
Background Mutations in several subunits of eukaryotic translation initiation factor 3 (eIF3) cause male transmission defects in Arabidopsis thaliana. To identify the stage of pollen development at which eIF3 becomes essential it is desirable to examine viable pollen and distinguish mutant from wild type. To accomplish this we have developed a broadly applicable method to track mutant alleles that are not already tagged by a visible marker gene through the male lineage of Arabidopsis. Methodology/Principal Findings Fluorescence tagged lines (FTLs) harbor a transgenic fluorescent protein gene (XFP) expressed by the pollen-specific LAT52 promoter at a defined chromosomal position. In the existing collection of FTLs there are enough XFP marker genes to track nearly every nuclear gene by virtue of its genetic linkage to a transgenic marker gene. Using FTLs in a quartet mutant, which yields mature pollen tetrads, we determined that the pollen transmission defect of the eif3h-1 allele is due to a combination of reduced pollen germination and reduced pollen tube elongation. We also detected reduced pollen germination for eif3e. However, neither eif3h nor eif3e, unlike other known gametophytic mutations, measurably disrupted the early stages of pollen maturation. Conclusion/Significance eIF3h and eIF3e both become essential during pollen germination, a stage of vigorous translation of newly transcribed mRNAs. These data delimit the end of the developmental window during which paternal rescue is still possible. Moreover, the FTL collection of mapped fluorescent protein transgenes represents an attractive resource for elucidating the pollen development phenotypes of any fine-mapped mutation in Arabidopsis.
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Affiliation(s)
- Bijoyita Roy
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee, United States of America
| | - Gregory P. Copenhaver
- Department of Biology and the Carolina Center for Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Lineberger Comprehensive Cancer Center, The University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Albrecht G. von Arnim
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee, United States of America
- * E-mail:
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29
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McCue AD, Cresti M, Feijó JA, Slotkin RK. Cytoplasmic connection of sperm cells to the pollen vegetative cell nucleus: potential roles of the male germ unit revisited. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:1621-31. [PMID: 21357775 DOI: 10.1093/jxb/err032] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The male germ cells of angiosperm plants are neither free-living nor flagellated and therefore are dependent on the unique structure of the pollen grain for fertilization. During angiosperm male gametogenesis, an asymmetric mitotic division produces the generative cell, which is completely enclosed within the cytoplasm of the larger pollen grain vegetative cell. Mitotic division of the generative cell generates two sperm cells that remain connected by a common extracellular matrix with potential intercellular connections. In addition, one sperm cell has a cytoplasmic projection in contact with the vegetative cell nucleus. The shared extracellular matrix of the two sperm cells and the physical association of one sperm cell to the vegetative cell nucleus forms a linkage of all the genetic material in the pollen grain, termed the male germ unit. Found in species representing both the monocot and eudicot lineages, the cytoplasmic projection is formed by vesicle formation and microtubule elongation shortly after the formation of the generative cell and tethers the male germ unit until just prior to fertilization. The cytoplasmic projection plays a structural role in linking the male germ unit, but potentially plays other important roles. Recently, it has been speculated that the cytoplasmic projection and the male germ unit may facilitate communication between the somatic vegetative cell nucleus and the germinal sperm cells, via RNA and/or protein transport. This review focuses on the nature of the sperm cell cytoplasmic projection and the potential communicative function of the male germ unit.
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Affiliation(s)
- Andrea D McCue
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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30
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Forsthoefel NR, Dao TP, Vernon DM. PIRL1 and PIRL9, encoding members of a novel plant-specific family of leucine-rich repeat proteins, are essential for differentiation of microspores into pollen. PLANTA 2010; 232:1101-1114. [PMID: 20697737 DOI: 10.1007/s00425-010-1242-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 07/26/2010] [Indexed: 05/29/2023]
Abstract
Plant intracellular Ras-group-related leucine-rich repeat proteins (PIRLs) are a plant-specific class of leucine-rich repeat (LRR) proteins related to animal and fungal LRRs that take part in developmental signaling and gene regulation. As part of a systematic functional study of the Arabidopsis thaliana PIRL gene family, T-DNA knockout mutants defective in the closely related PIRL1 and PIRL9 genes were identified and characterized. Pirl1 and pirl9 single mutants displayed normal transmission and did not exhibit an obvious developmental phenotype. To investigate the possibility of functional redundancy, crosses to generate double mutants were carried out; however, pirl1;pirl9 plants were not recovered. Reciprocal crosses between wild type and pirl1/PIRL1;pirl9 plants, which produce 50% pirl1;pirl9 gametophytes, indicated male-specific transmission failure of the double-mutant allele combination. Scanning electron microscopy and viability staining showed that approximately half of the pollen produced by pirl1/PIRL1;pirl9 plants was inviable and severely malformed. Tetrad analyses with qrt1 indicated that pollen defects segregated with the double-mutant allele combination, thus demonstrating that PIRL1 and PIRL9 function after meiosis. Pollen development was characterized with bright field, fluorescence, and transmission electron microscopy. Pirl1;pirl9 mutants stopped growing as microspores, failed to initiate vacuolar fission, aborted, and underwent cytoplasmic degeneration. Development consistently arrested at the late microspore stage, just prior to pollen mitosis I. Thus, PIRL1 and PIRL9 have redundant roles essential at a key transition point early in pollen development. Together, these results define a functional context for these two members of this distinct class of plant LRR genes.
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31
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Oh SA, Pal MD, Park SK, Johnson JA, Twell D. The tobacco MAP215/Dis1-family protein TMBP200 is required for the functional organization of microtubule arrays during male germline establishment. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:969-81. [PMID: 20022922 PMCID: PMC2826647 DOI: 10.1093/jxb/erp367] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 11/09/2009] [Accepted: 11/18/2009] [Indexed: 05/19/2023]
Abstract
The haploid microspore division during pollen development in flowering plants is an intrinsically asymmetric division which establishes the male germline for sexual reproduction. Arabidopsis gem1 mutants lack the male germline as a result of disturbed microspore polarity, division asymmetry, and cytokinesis and represent loss-of-function mutants in MOR1/GEM1, a plant orthologue of the conserved MAP215/Dis1 microtubule associated protein (MAP) family. This provides genetic evidence for the role of MAP215/Dis1 in the organization of gametophytic microtubule arrays, but it has remained unknown how microtubule arrays are affected in gem1 mutant microspores. Here, novel male gametophytic microtubule-reporter Nicotiana tabacum plants were constructed, expressing a green fluorescent protein-alpha-TUBULIN fusion protein (GFP-TUA6) under the control of a microspore-specific promoter. These plants allow effective visualization of all major male gametophytic microtubule arrays and provide useful tools to study the regulation of microtubule arrays by MAPs and other effectors. Depletion of TMBP200, a tobacco homologue of MOR1/GEM1 in gametophytic microtubule-reporter plants using microspore-targeted RNA interference, induced defects in microspore polarity, division asymmetry and cytokinesis that were associated with striking defects in phragmoplast position, orientation, and structure. Our observations further reveal a requirement for TMBP200 in gametophytic spindle organization and a novel role in spindle position and orientation in polarized microspores. These results provide direct evidence for the function of MAP215/Dis1 family protein TMBP200 in the organization of microtubule arrays critical for male germline formation in plants.
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Affiliation(s)
- Sung Aeong Oh
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
- Division of Plant Biosciences, Kyungpook National University, Daegu 702-701, South Korea
| | - Madhumita Das Pal
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Soon Ki Park
- Division of Plant Biosciences, Kyungpook National University, Daegu 702-701, South Korea
| | - James Andrew Johnson
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
| | - David Twell
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
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32
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Kägi C, Gross-Hardt R. Analyzing female gametophyte development and function: There is more than one way to crack an egg. Eur J Cell Biol 2009; 89:258-61. [PMID: 20018400 DOI: 10.1016/j.ejcb.2009.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
In flowering plants, gametes are formed in specialized haploid structures, termed gametophytes. The female gametophyte is a few-celled structure that integrates such diverse functions as pollen tube attraction, sperm cell release, gamete fusion and seed initiation. These processes are realized by distinct cell types, which ensure reproductive success in a coordinated manner. In the past decade, much progress has been made concerning the molecular nature of the functions carried out by the different cell types. Here, we review recent work that has shed light on female gametophyte development and function with a particular focus on approaches that have led to the isolation of genes involved in these processes.
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Affiliation(s)
- Christina Kägi
- ZMBP Developmental Genetics, University of Tübingen, Auf der Morgenstelle 1, 72076 Tübingen, Germany
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33
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Hirano T, Hoshino Y. Sperm dimorphism in terms of nuclear shape and microtubule accumulation in Cyrtanthus mackenii. ACTA ACUST UNITED AC 2009; 23:153-62. [DOI: 10.1007/s00497-009-0123-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
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34
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Boavida LC, Shuai B, Yu HJ, Pagnussat GC, Sundaresan V, McCormick S. A collection of Ds insertional mutants associated with defects in male gametophyte development and function in Arabidopsis thaliana. Genetics 2009; 181:1369-85. [PMID: 19237690 PMCID: PMC2666506 DOI: 10.1534/genetics.108.090852] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 02/13/2009] [Indexed: 11/18/2022] Open
Abstract
Functional analyses of the Arabidopsis genome require analysis of the gametophytic generation, since approximately 10% of the genes are expressed in the male gametophyte and approximately 9% in the female gametophyte. Here we describe the genetic and molecular characterization of 67 Ds insertion lines that show reduced transmission through the male gametophyte. About half of these mutations are male gametophytic-specific mutations, while the others also affect female transmission. Genomic sequences flanking both sides of the Ds element were recovered for 39 lines; for 16 the Ds elements were inserted in or close to coding regions, while 7 were located in intergenic/unannotated regions of the genome. For the remaining 16 lines, chromosomal rearrangements such as translocations or deletions, ranging between 30 and 500 kb, were associated with the transposition event. The mutants were classified into five groups according to the developmental processes affected; these ranged from defects in early stages of gametogenesis to later defects affecting pollen germination, pollen tube growth, polarity or guidance, or pollen tube-embryo sac interactions or fertilization. The isolated mutants carry Ds insertions in genes with diverse biological functions and potentially specify new functions for several unannotated or unknown proteins.
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Affiliation(s)
- Leonor C Boavida
- Plant Gene Expression Center and Plant and Microbial Biology, US Department of Agriculture/Agricultural Research Service, Albany, California 94710, USA
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35
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Han S, Green L, Schnell DJ. The signal peptide peptidase is required for pollen function in Arabidopsis. PLANT PHYSIOLOGY 2009; 149:1289-1301. [PMID: 19168645 PMCID: PMC2649412 DOI: 10.1104/pp.108.130252] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Accepted: 01/20/2009] [Indexed: 05/27/2023]
Abstract
The Signal Peptide Peptidases (SPP) are members of the Intramembrane Cleaving Proteases, which are involved in an array of protein-processing and intracellular signaling events in animals. Arabidopsis (Arabidopsis thaliana) has six genes encoding SPP-like proteins, the physiological functions of which are unknown. As a first step in defining the roles of the SPPs in plants, we examined the distribution and activities of Arabidopsis SPP (AtSPP; accession no. At2g03120), the SPP-like gene with the highest degree of similarity to human SPP. The protease is expressed at low levels throughout the plant, with the highest levels in emerging leaves, roots, and floral tissues. Homozygous plants carrying a T-DNA insertion mutation in AtSPP, spp-2, could not be recovered, and transmission of the mutant allele through pollen was reduced to less than 2% in reciprocal cross experiments. Although viable, pollen from spp-2 heterozygous plants exhibited a 50% reduction in germination rate and a disruption in male germ unit organization. These data demonstrate that AtSPP is required for male gametophyte development and pollen maturation in Arabidopsis.
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Affiliation(s)
- Sungwon Han
- Department of Biochemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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36
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Borg M, Brownfield L, Twell D. Male gametophyte development: a molecular perspective. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:1465-78. [PMID: 19213812 DOI: 10.1093/jxb/ern355] [Citation(s) in RCA: 215] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Pollen grains represent the highly reduced haploid male gametophyte generation in flowering plants, consisting of just two or three cells when released from the anthers. Their role is to deliver twin sperm cells to the embryo sac to undergo fusion with the egg and central cell. This double fertilization event along with the functional specialization of the male gametophyte, are considered to be key innovations in the evolutionary success of flowering plants. This review encompasses important recent advances in our understanding of the molecular mechanisms controlling male gametophyte development. A brief overview of pollen development is presented, followed by a discussion of genome-wide transcriptomic studies of haploid gene expression. The progress achieved through genetic analysis of landmark events of male gametogenesis is discussed, with a focus on sperm cell production, and an emerging model of the regulatory network governing male germline development is presented. The review concludes with a perspective of the impact these data will have on future research strategies to further develop our understanding of the gametophytic control of pollen development.
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Affiliation(s)
- Michael Borg
- Department of Biology, University of Leicester, UK
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37
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Moll C, Nielsen N, Gross-Hardt R. Mutants with aberrant numbers of gametic cells shed new light on old questions. PLANT BIOLOGY (STUTTGART, GERMANY) 2008; 10:529-533. [PMID: 18761491 DOI: 10.1111/j.1438-8677.2008.00127.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In contrast to animals, plant gametes form in distinct haploid generations, termed gametophytes. The female gametophyte of Arabidopsis consists of two gametic cells, the egg and central cell, which are flanked by accessory cells. The gametic cells differ with respect to morphology, molecular attributes and, importantly, their fate: whereas the egg cell, upon fertilisation, gives rise to the embryo, the central cell forms the endosperm. To ensure correct endosperm formation, not only the egg cell but also the central cell has to fuse with a sperm cell. The respective sperm cell pair is delivered by a single pollen tube. In some plant species, the two male gametes appear to express a different bias towards the female gametes. Such a preference consequently determines their respective contribution to either embryo or endosperm development. In Arabidopsis and many other species the sperm cells are indistinguishable and it has been discussed whether they possess an inherent preference for either of the female gametes. The recent isolation of mutants that form an aberrant number of either male or female gametes stimulates discussion, albeit with different results. Furthermore, some data indicate that the central cell is competent to initiate endosperm formation without a paternal contribution. These data support the theory that the endosperm is of gametophytic rather than sporophytic origin.
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Affiliation(s)
- C Moll
- Center for Plant Molecular Biology (ZMBP) Developmental Genetics, University of Tübingen, Tübingen, Germany
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38
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Hiscock SJ, Allen AM. Diverse cell signalling pathways regulate pollen-stigma interactions: the search for consensus. THE NEW PHYTOLOGIST 2008; 179:286-317. [PMID: 19086285 DOI: 10.1111/j.1469-8137.2008.02457.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Siphonogamy, the delivery of nonmotile sperm to the egg via a pollen tube, was a key innovation that allowed flowering plants (angiosperms) to carry out sexual reproduction on land without the need for water. This process begins with a pollen grain (male gametophyte) alighting on and adhering to the stigma of a flower. If conditions are right, the pollen grain germinates to produce a pollen tube. The pollen tube invades the stigma and grows through the style towards the ovary, where it enters an ovule, penetrates the embryo sac (female gametophyte) and releases two sperm cells, one of which fertilizes the egg, while the other fuses with the two polar nuclei of the central cell to form the triploid endosperm. The events before fertilization (pollen-pistil interactions) comprise a series of complex cellular interactions involving a continuous exchange of signals between the haploid pollen and the diploid maternal tissue of the pistil (sporophyte). In recent years, significant progress has been made in elucidating the molecular identity of these signals and the cellular interactions that they regulate. Here we review our current understanding of the cellular and molecular interactions that mediate the earliest of these interactions between the pollen and the pistil that occur on or within the stigma - the 'pollen-stigma interaction'.
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Affiliation(s)
- Simon J Hiscock
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
| | - Alexandra M Allen
- School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
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39
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Liu J, Qu LJ. Meiotic and mitotic cell cycle mutants involved in gametophyte development in Arabidopsis. MOLECULAR PLANT 2008; 1:564-74. [PMID: 19825562 DOI: 10.1093/mp/ssn033] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The alternation between diploid and haploid generations is fundamental in the life cycles of both animals and plants. The meiotic cell cycle is common to both animals and plants gamete formation, but in animals the products of meiosis are gametes, whereas for most plants, subsequent mitotic cell cycles are needed for their formation. Clarifying the regulatory mechanisms of mitotic cell cycle progression during gametophyte development will help understanding of sexual reproduction in plants. Many mutants defective in gametophyte development and, in particular, many meiotic and mitotic cell cycle mutants in Arabidopsis male and female gametophyte development were identified through both forward and reverse genetics approaches.
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Affiliation(s)
- Jingjing Liu
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, People's Republic of China
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40
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Coelho SM, Peters AF, Charrier B, Roze D, Destombe C, Valero M, Cock JM. Complex life cycles of multicellular eukaryotes: new approaches based on the use of model organisms. Gene 2007; 406:152-70. [PMID: 17870254 DOI: 10.1016/j.gene.2007.07.025] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 07/18/2007] [Accepted: 07/19/2007] [Indexed: 01/01/2023]
Abstract
A wide variety of life cycles can be found in the different groups of multicellular eukaryotes. Here we provide an overview of this variety, and review some of the theoretical arguments that have been put forward to explain the evolutionary stability of different life cycle strategies. We also describe recent progress in the analysis of the haploid-diploid life cycle of the model angiosperm Arabidopsis thaliana and show how new molecular data are providing a means to test some of the theoretical predictions. Finally, we describe an emerging model organism from the brown algae, Ectocarpus siliculosus, and highlight the potential of this system for the investigation of the mechanisms that regulate complex life cycles.
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Affiliation(s)
- Susana M Coelho
- The Marine Plants and Biomolecules Laboratory, UMR 7139 Centre National de la Recherche Scientifique and Université Pierre et Marie Curie, Station Biologique de Roscoff, Place Georges Teissier, BP74, 29682 Roscoff Cedex, France
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41
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Yang H, Li W, Chen S. Isolation and characterization of 4 gametophytic male sterile mutants in Arabidopsis thaliana. CHINESE SCIENCE BULLETIN-CHINESE 2007. [DOI: 10.1007/s11434-007-0279-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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42
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Qin G, Ma Z, Zhang L, Xing S, Hou X, Deng J, Liu J, Chen Z, Qu LJ, Gu H. Arabidopsis AtBECLIN 1/AtAtg6/AtVps30 is essential for pollen germination and plant development. Cell Res 2007; 17:249-63. [PMID: 17339883 DOI: 10.1038/cr.2007.7] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pollen germination on the surface of compatible stigmatic tissues is an essential step for plant fertilization. Here we report that the Arabidopsis mutant bcl1 is male sterile as a result of the failure of pollen germination. We show that the bcl1 mutant allele cannot be transmitted by male gametophytes and no homozygous bcl1 mutants were obtained. Analysis of pollen developmental stages indicates that the bcl1 mutation affects pollen germination but not pollen maturation. Molecular analysis demonstrates that the failure of pollen germination was caused by the disruption of AtBECLIN 1. AtBECLIN 1 is expressed predominantly in mature pollen and encodes a protein with significant homology to Beclin1/Atg6/Vps30 required for the processes of autophagy and vacuolar protein sorting (VPS) in yeast. We also show that AtBECLIN 1 is required for normal plant development, and that genes related to autophagy, VPS and the glycosylphosphatidylinositol anchor system, were affected by the deficiency of AtBECLIN 1.
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Affiliation(s)
- Genji Qin
- National Laboratory for Protein Engineering and Plant Genetic Engineering, Peking-Yale Joint Research Center for Plant Molecular Genetics and AgroBiotechnology, College of Life Sciences, Peking University, Beijing, China
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43
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Blackmore S, Wortley AH, Skvarla JJ, Rowley JR. Pollen wall development in flowering plants. THE NEW PHYTOLOGIST 2007; 174:483-498. [PMID: 17447905 DOI: 10.1111/j.1469-8137.2007.02060.x] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The outer pollen wall, or exine, is more structurally complex than any other plant cell wall, comprising several distinct layers, each with its own organizational pattern. Since elucidation of the basic events of pollen wall ontogeny using electron microscopy in the 1970s, knowledge of their developmental genetics has increased enormously. However, self-assembly processes that are not under direct genetic control also play an important role in pollen wall patterning. This review integrates ultrastructural and developmental findings with recent models for self-assembly in an attempt to understand the origins of the morphological complexity and diversity that underpin the science of palynology.
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Affiliation(s)
- Stephen Blackmore
- Royal Botanic Garden Edinburgh, 20a Inverleith Row, Edinburgh EH3 5LR, UK
| | | | - John J Skvarla
- Department of Botany - Microbiology, University of Oklahoma, Norman, OK 73019-0245, USA
| | - John R Rowley
- Botany Department, University of Stockholm, SE-106 91, Stockholm, Sweden
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Pawloski LC, Kandasamy MK, Meagher RB. The late pollen actins are essential for normal male and female development in Arabidopsis. PLANT MOLECULAR BIOLOGY 2006; 62:881-96. [PMID: 17031513 DOI: 10.1007/s11103-006-9063-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Accepted: 07/19/2006] [Indexed: 05/12/2023]
Abstract
In angiosperms the late pollen actins (LPAs) are strongly expressed in mature pollen and pollen tubes and at much lower levels in ovules. Four Arabidopsis lines with homozygous knockout mutations in the four individual LPA genes displayed normal flowers, pollen, and seed set. However, when all four LPAs were silenced simultaneously with a single RNA interference (RNAi) construct targeting the 3'UTR of each mRNA, obvious reproductive defects were observed. Western analysis of various Late Pollen actin RNA interference (LPRi) epialleles showed total LPA protein and RNA expression levels were knocked down from 0% to 95% compared to wild-type levels. Reciprocal crosses with the RNAi lines demonstrated that lowered LPA expression was associated with defects in both male and female fertility. Strong epialleles showed significant reductions in normal silique and seed production and were nearly sterile. Dissection of the siliques from moderate LPRi epialleles revealed many unfertilized ovules, increased numbers of aborted seeds, and decreased numbers of healthy seeds. Microscopic analysis of LPRi pollen indicated that the pollen shape and size were normal, but pollen germinated poorly. While multiple LPA genes may have some functional redundancy, the combined expression of multiple LPA genes appears essential to normal male and female reproductive development.
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Affiliation(s)
- Lucia Cardenas Pawloski
- Department of Genetics, Life Sciences Building, University of Georgia, Athens, GA 30602, USA
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45
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Han MJ, Jung KH, Yi G, Lee DY, An G. Rice Immature Pollen 1 (RIP1) is a regulator of late pollen development. PLANT & CELL PHYSIOLOGY 2006; 47:1457-72. [PMID: 16990291 DOI: 10.1093/pcp/pcl013] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We isolated a pollen-preferential gene, RICE IMMATURE POLLEN 1 (RIP1), from a T-DNA insertional population of japonica rice that was trapped by a promoterless beta-glucuronidase (GUS) gene. Semi-quantitative reverse transcription-PCR (RT-PCR) analyses confirmed that the RIP1 transcript was abundant at the late stages of pollen development. Transgenic plants carrying a T-DNA insertion in the RIP1 gene displayed the phenotype of segregation distortion of the mutated rip1 gene. Moreover, rip1/rip1 homozygous progeny were not present. Reciprocal crosses between Rip1/rip1 heterozygous plants and the wild type showed that the rip1 allele could not be transmitted through the male. Microscopic analysis demonstrated that development in the rip1 pollen was delayed, starting at the early vacuolated stage. Close examination of that pollen by transmission electron microscopy also showed delayed formation of starch granules and the intine layer. In addition, development of the mitochondria, Golgi apparatus, lipid bodies, plastids and endoplasmic reticulum was deferred in the mutant pollen. Under in vitro conditions, germination of this mutant pollen did not occur, whereas the rate for wild-type pollen was >90%. These results indicate that RIP1 is necessary for pollen maturation and germination. This gene encodes a protein that shares significant homology with a group of proteins containing five WD40 repeat sequences. The green fluorescent protein (GFP)-RIP1 fusion protein is localized to the nucleus. Therefore, RIP1 is probably a nuclear protein that may form a functional complex with other proteins and carry out essential cellular and developmental roles during the late stage of pollen formation.
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Affiliation(s)
- Min-Jung Han
- National Research Laboratory of Plant Functional Genomics, Division of Molecular and Life Sciences, Republic of Korea
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46
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Jakobsen MK, Poulsen LR, Schulz A, Fleurat-Lessard P, Møller A, Husted S, Schiøtt M, Amtmann A, Palmgren MG. Pollen development and fertilization in Arabidopsis is dependent on the MALE GAMETOGENESIS IMPAIRED ANTHERS gene encoding a type V P-type ATPase. Genes Dev 2005; 19:2757-69. [PMID: 16291648 PMCID: PMC1283967 DOI: 10.1101/gad.357305] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In flowering plants, development of the haploid male gametophytes (pollen grains) takes place in a specialized structure called the anther. Successful pollen development, and thus reproduction, requires high secretory activity in both anther tissues and pollen. In this paper, we describe a novel member of the eukaryotic type V subfamily (P(5)) of P-type ATPase cation pumps, the MALE GAMETOGENESIS IMPAIRED ANTHERS (MIA) gene. MIA protein is highly abundant in the endoplasmic reticulum and small vesicles of developing pollen grains and tapetum cells. T-DNA insertional mutants of MIA suffer from imbalances in cation homeostasis and exhibit a severe reduction in fertility. Mutant microspores fail to separate from tetrads and pollen grains are fragile with an abnormal morphology and altered cell wall structure. Disruption of MIA affects expression of genes essential for secretion as well as a high number of genes encoding cell wall proteins and membrane transporters. MIA functionally complements a mutant in the P(5) ATPase homolog SPF1 from Saccharomyces cerevisiae, suggesting a common function for P(5) ATPases in single and multicellular organisms. Our results suggest that MIA is required in the secretory pathway for proper secretion of vesicle cargo to the plasma membrane.
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Affiliation(s)
- Mia Kyed Jakobsen
- Department of Plant Biology, The Royal Veterinary and Agricultural University, Frederiksberg C, Denmark
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47
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Engel ML, Holmes-Davis R, McCormick S. Green sperm. Identification of male gamete promoters in Arabidopsis. PLANT PHYSIOLOGY 2005; 138:2124-33. [PMID: 16055690 PMCID: PMC1183400 DOI: 10.1104/pp.104.054213] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Previously, in an effort to better understand the male contribution to fertilization, we completed a maize (Zea mays) sperm expressed sequence tag project. Here, we used this resource to identify promoters that would direct gene expression in sperm cells. We used reverse transcription-polymerase chain reaction to identify probable sperm-specific transcripts in maize and then identified their best sequence matches in the Arabidopsis (Arabidopsis thaliana) genome. We tested five different Arabidopsis promoters for cell specificity, using an enhanced green fluorescent protein reporter gene. In pollen, the AtGEX1 (At5g55490) promoter is active in the sperm cells and not in the progenitor generative cell or in the vegetative cell, but it is also active in ovules, roots, and guard cells. The AtGEX2 (At5g49150) promoter is active only in the sperm cells and in the progenitor generative cell, but not in the vegetative cell or in other tissues. A third promoter, AtVEX1 (At5g62850) [corrected] was active in the vegetative cell during the later stages of pollen development; the other promoters tested (At1g66770 and At1g73350) did not function in pollen. Comparisons among GEX1 and GEX2 homologs from maize, rice (Oryza sativa), Arabidopsis, and poplar (Populus trichocarpa) revealed a core binding site for Dof transcription factors. The AtGEX1 and AtGEX2 promoters will be useful for manipulating gene expression in sperm cells, for localization and functional analyses of sperm proteins, and for imaging of sperm dynamics as they are transported in the pollen tube to the embryo sac.
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Affiliation(s)
- Michele L Engel
- Plant Gene Expression Center, United States Department of Agriculture, Agricultural Research Service, Albany, California 94710, USA
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Rotman N, Durbarry A, Wardle A, Yang WC, Chaboud A, Faure JE, Berger F, Twell D. A novel class of MYB factors controls sperm-cell formation in plants. Curr Biol 2005; 15:244-8. [PMID: 15694308 DOI: 10.1016/j.cub.2005.01.013] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 11/18/2004] [Accepted: 11/19/2004] [Indexed: 11/23/2022]
Abstract
In contrast to animals, the plant male germline is established after meiosis in distinctive haploid structures, termed pollen grains. The germline arises by a distinct asymmetric division of the meiotic products . The fates of the resulting vegetative and generative cells are distinct. In contrast to the larger vegetative cell, arrested in the G1 phase of the cell cycle, the smaller generative cell divides once to produce the two male gametes or sperm cells. Sperm cells are delivered to the female gametes by the pollen tube, which develops from the vegetative cell. In spite of recent efforts to understand pollen development , the molecular pathway controlling sperm-cell ontogenesis is unknown. Here, we present the isolation of DUO1, a novel R2R3 MYB gene of Arabidopsis, as the first gene shown to control male gamete formation in plants. DUO1 is specifically expressed in the male germline, and DUO1 protein accumulates in sperm-cell nuclei. Mutations in DUO1 produce a single larger diploid sperm cell unable to perform fertilization. DUO1 appears to be evolutionarily conserved in several plant species and defines a new subfamily of pollen-specific MYB genes.
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Affiliation(s)
- Nicolas Rotman
- Reproduction et Développement des Plantes, Unité Mixte de Recherche 5667, Institut Fédératif de Recherche 128, Centre National de la Recherche Scientifique, Université Claude Bernard Lyon I, 46 allée d'Italie, F-69364 Lyon Cedex 07, France
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49
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The division of the generative nucleus and the formation of callose plugs in pollen tubes of Aechmea fasciata (Bromeliaceae) cultured in vitro. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/s00497-005-0243-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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50
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Lalanne E, Michaelidis C, Moore JM, Gagliano W, Johnson A, Patel R, Howden R, Vielle-Calzada JP, Grossniklaus U, Twell D. Analysis of transposon insertion mutants highlights the diversity of mechanisms underlying male progamic development in Arabidopsis. Genetics 2005; 167:1975-86. [PMID: 15342534 PMCID: PMC1471024 DOI: 10.1534/genetics.104.030270] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
To identify genes with essential roles in male gametophytic development, including postpollination (progamic) events, we have undertaken a genetic screen based on segregation ratio distortion of a transposon-borne kanamycin-resistance marker. In a population of 3359 Arabidopsis Ds transposon insertion lines, we identified 20 mutants with stably reduced segregation ratios arising from reduced gametophytic transmission. All 20 mutants showed strict cosegregation of Ds and the reduced gametophytic transmission phenotype. Among these, 10 mutants affected both male and female transmission and 10 mutants showed male-specific transmission defects. Four male and female (ungud) mutants and 1 male-specific mutant showed cellular defects in microspores and/or in developing pollen. The 6 remaining ungud mutants and 9 male-specific (seth) mutants affected pollen functions during progamic development. In vitro and in vivo analyses are reported for 5 seth mutants. seth6 completely blocked pollen germination, while seth7 strongly reduced pollen germination efficiency and tube growth. In contrast, seth8, seth9, or seth10 pollen showed reduced competitive ability that was linked to slower rates of pollen tube growth. Gene sequences disrupted in seth insertions suggest essential functions for putative SETH proteins in diverse processes including protein anchoring, cell wall biosynthesis, signaling, and metabolism.
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Affiliation(s)
- Eric Lalanne
- Department of Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
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