1
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Meng JG, Li SZ, Li HJ. Central cell: the key to determine persistent pollen tube attraction or termination. SCIENCE CHINA. LIFE SCIENCES 2024:10.1007/s11427-023-2534-2. [PMID: 38733514 DOI: 10.1007/s11427-023-2534-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 01/25/2024] [Indexed: 05/13/2024]
Affiliation(s)
- Jiang-Guo Meng
- Center for Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, Integrative Science Center of Germplasm Creation Western China (Chongqing) Science City, School of Life Sciences, Southwest University, Chongqing, 400715, China
| | - Shi-Zhen Li
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- Center for Molecular Agrobiology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hong-Ju Li
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
- Center for Molecular Agrobiology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
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2
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Zhong S, Zhao P, Peng X, Li HJ, Duan Q, Cheung AY. From gametes to zygote: Mechanistic advances and emerging possibilities in plant reproduction. PLANT PHYSIOLOGY 2024; 195:4-35. [PMID: 38431529 PMCID: PMC11060694 DOI: 10.1093/plphys/kiae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/13/2024] [Accepted: 02/13/2024] [Indexed: 03/05/2024]
Affiliation(s)
- Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, College of Life Sciences, Peking University, Beijing 100871, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Hong-Ju Li
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Center for Molecular Agrobiology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiaohong Duan
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, Shandong 271018, China
| | - Alice Y Cheung
- Department of Biochemistry and Molecular Biology, Molecular and Cellular Biology Program, Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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3
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Meng JG, Xu YJ, Wang WQ, Yang F, Chen SY, Jia PF, Yang WC, Li HJ. Central-cell-produced attractants control fertilization recovery. Cell 2023; 186:3593-3605.e12. [PMID: 37516107 DOI: 10.1016/j.cell.2023.06.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 03/13/2023] [Accepted: 06/26/2023] [Indexed: 07/31/2023]
Abstract
Animal fertilization relies on hundreds of sperm racing toward the egg, whereas, in angiosperms, only two sperm cells are delivered by a pollen tube to the female gametes (egg cell and central cell) for double fertilization. However, unsuccessful fertilization under this one-pollen-tube design can be detrimental to seed production and plant survival. To mitigate this risk, unfertilized-gamete-controlled extra pollen tube entry has been evolved to bring more sperm cells and salvage fertilization. Despite its importance, the underlying molecular mechanism of this phenomenon remains unclear. In this study, we report that, in Arabidopsis, the central cell secretes peptides SALVAGER1 and SALVAGER2 in a directional manner to attract pollen tubes when the synergid-dependent attraction fails or is terminated by pollen tubes carrying infertile sperm cells. Moreover, loss of SALs impairs the fertilization recovery capacity of the ovules. Therefore, this research uncovers a female gamete-attraction system that salvages seed production for reproductive assurance.
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Affiliation(s)
- Jiang-Guo Meng
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yin-Jiao Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei-Qi Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shu-Yan Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Peng-Fei Jia
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong-Ju Li
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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4
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Zhang R, Shi PT, Zhou M, Liu HZ, Xu XJ, Liu WT, Chen KM. Rapid alkalinization factor: function, regulation, and potential applications in agriculture. STRESS BIOLOGY 2023; 3:16. [PMID: 37676530 PMCID: PMC10442051 DOI: 10.1007/s44154-023-00093-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 05/10/2023] [Indexed: 09/08/2023]
Abstract
Rapid alkalinization factor (RALF) is widespread throughout the plant kingdom and controls many aspects of plant life. Current studies on the regulatory mechanism underlying RALF function mainly focus on Arabidopsis, but little is known about the role of RALF in crop plants. Here, we systematically and comprehensively analyzed the relation between RALF family genes from five important crops and those in the model plant Arabidopsis thaliana. Simultaneously, we summarized the functions of RALFs in controlling growth and developmental behavior using conservative motifs as cues and predicted the regulatory role of RALFs in cereal crops. In conclusion, RALF has considerable application potential in improving crop yields and increasing economic benefits. Using gene editing technology or taking advantage of RALF as a hormone additive are effective way to amplify the role of RALF in crop plants.
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Affiliation(s)
- Ran Zhang
- State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Peng-Tao Shi
- State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Min Zhou
- State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Huai-Zeng Liu
- State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Xiao-Jing Xu
- State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Wen-Ting Liu
- State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Kun-Ming Chen
- State Key Laboratory of Crop Stress Biology in Arid Area, College of Life Sciences, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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5
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Sugi N, Maruyama D. Exploring Novel Polytubey Reproduction Pathways Utilizing Cumulative Genetic Tools. PLANT & CELL PHYSIOLOGY 2023; 64:454-460. [PMID: 36943745 DOI: 10.1093/pcp/pcad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/11/2023] [Accepted: 03/19/2023] [Indexed: 05/17/2023]
Abstract
In the anthers and ovaries of flowers, pollen grains and embryo sacs are produced with uniform cell compositions. This stable gametogenesis enables elaborate interactions between male and female gametophytes after pollination, forming the highly successful sexual reproduction system in flowering plants. As most ovules are fertilized with a single pollen tube, the resulting genome set in the embryo and endosperm is determined in a single pattern by independent fertilization of the egg cell and central cell by two sperm cells. However, if ovules receive four sperm cells from two pollen tubes, the expected options for genome sets in the developing seeds would more than double. In wild-type Arabidopsis thaliana plants, around 5% of ovules receive two pollen tubes. Recent studies have elucidated the abnormal fertilization in supernumerary pollen tubes and sperm cells related to polytubey, polyspermy, heterofertilization and fertilization recovery. Analyses of model plants have begun to uncover the mechanisms underlying this new pollen tube biology. Here, we review unusual fertilization phenomena and propose several breeding applications for flowering plants. These arguments contribute to the remodeling of plant reproduction, a challenging concept that alters typical plant fertilization by utilizing the current genetic toolbox.
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Affiliation(s)
- Naoya Sugi
- Kihara Institute for Biological Research, Yokohama City University, Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813 Japan
| | - Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, Maioka-cho, Totsuka-ku, Yokohama, Kanagawa, 244-0813 Japan
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6
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Shiba Y, Takahashi T, Ohashi Y, Ueda M, Mimuro A, Sugimoto J, Noguchi Y, Igawa T. Behavior of Male Gamete Fusogen GCS1/HAP2 and the Regulation in Arabidopsis Double Fertilization. Biomolecules 2023; 13:biom13020208. [PMID: 36830580 PMCID: PMC9953686 DOI: 10.3390/biom13020208] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
In the sexual reproduction of flowering plants, two independent fertilization events occur almost simultaneously: two identical sperm cells fuse with either the egg cell or the central cell, resulting in embryo and endosperm development to produce a seed. GCS1/HAP2 is a sperm cell membrane protein essential for plasma membrane fusion with both female gametes. Other sperm membrane proteins, DMP8 and DMP9, are more important for egg cell fertilization than that of the central cell, suggesting its regulatory mechanism in GCS1/HAP2-driving gamete membrane fusion. To assess the GCS1/HAP2 regulatory cascade in the double fertilization system of flowering plants, we produced Arabidopsis transgenic lines expressing different GCS1/HAP2 variants and evaluated the fertilization in vivo. The fertilization pattern observed in GCS1_RNAi transgenic plants implied that sperm cells over the amount of GCS1/HAP2 required for fusion on their surface could facilitate membrane fusion with both female gametes. The cytological analysis of the dmp8dmp9 sperm cell arrested alone in an embryo sac supported GCS1/HAP2 distribution on the sperm surface. Furthermore, the fertilization failures with both female gametes were caused by GCS1/HAP2 secretion from the egg cell. These results provided a possible scenario of GCS1/HAP2 regulation, showing a potential scheme for capturing additional GCS1/HAP2-interacting proteins.
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Affiliation(s)
- Yuka Shiba
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Taro Takahashi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Yukino Ohashi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Minako Ueda
- Graduate School of Life Sciences, Department of Ecological Developmental Adaptability Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
- Suntory Rising Stars Encouragement Program in Life Sciences (SunRiSE), Sendai 980-8578, Japan
| | - Amane Mimuro
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Jin Sugimoto
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Yuka Noguchi
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
| | - Tomoko Igawa
- Graduate School of Horticulture, Chiba University, Matsudo 648, Matsudo-shi 271-8510, Japan
- Plant Molecular Science Center, Chiba University, 1-33 Yayoi, Chiba-shi 263-8522, Japan
- Correspondence:
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7
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Cheung AY, Duan Q, Li C, James Liu MC, Wu HM. Pollen-pistil interactions: It takes two to tangle but a molecular cast of many to deliver. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102279. [PMID: 36029655 DOI: 10.1016/j.pbi.2022.102279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 06/15/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Explosive advances have been made in the molecular understanding of pollen-pistil interactions that underlie reproductive success in flowering plants in the past three decades. Among the most notable is the discovery of pollen tube attractants [1∗,2∗]. The roles these molecules play in facilitating conspecific precedence thus promoting interspecific genetic isolation are also emerging [3-5]. Male-female interactions during the prezygotic phase and contributions from the male and female gametophytes have been comprehensively reviewed recently. Here, we focus on key advances in understanding the mechanistic underpinnings of how these interactions overcome barriers at various pollen-pistil interfaces along the pollen tube growth pathway to facilitate fertilization by desirable mates.
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Affiliation(s)
- Alice Y Cheung
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA; Molecular and Cell Biology Program, University of Massachusetts, Amherst, MA 01003, USA; Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA.
| | - Qiaohong Duan
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, Shandong, China; College of Horticultural Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, China
| | - Chao Li
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Ming-Che James Liu
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
| | - Hen-Ming Wu
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA; Molecular and Cell Biology Program, University of Massachusetts, Amherst, MA 01003, USA
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8
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Restricted Pollination for Tracing Individual Pollen Tubes in a Pistil. Methods Mol Biol 2021. [PMID: 32529429 DOI: 10.1007/978-1-0716-0672-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
As one of the essential steps to complete sexual reproduction, a pollen tube is precisely guided to an embryo sac to deliver the sperm cells. This ovule targeting by a pollen tube is one of the essential steps in pollen tube guidance. To assess the ovule targeting ability of the pollen tube from a certain mutant line, comparative analysis of pollen tube behaviors between wild-type and mutant genotypes is important. Here, we provide a protocol that traces all pollen tubes germinated from the quartet tetrad in a pistil by restricted pollination and aniline blue staining. By this analysis, statistical comparison between wild-type and the mutant pollen tube functions under the same in vivo condition is possible.
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9
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Adhikari PB, Liu X, Wu X, Zhu S, Kasahara RD. Fertilization in flowering plants: an odyssey of sperm cell delivery. PLANT MOLECULAR BIOLOGY 2020; 103:9-32. [PMID: 32124177 DOI: 10.1007/s11103-020-00987-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 02/26/2020] [Indexed: 05/22/2023]
Abstract
In light of the available discoveries in the field, this review manuscript discusses on plant reproduction mechanism and molecular players involved in the process. Sperm cells in angiosperms are immotile and are physically distant to the female gametophytes (FG). To secure the production of the next generation, plants have devised a clever approach by which the two sperm cells in each pollen are safely delivered to the female gametophyte where two fertilization events occur (by each sperm cell fertilizing an egg cell and central cell) to give rise to embryo and endosperm. Each of the successfully fertilized ovules later develops into a seed. Sets of macromolecules play roles in pollen tube (PT) guidance, from the stigma, through the transmitting tract and funiculus to the micropylar end of the ovule. Other sets of genetic players are involved in PT reception and in its rupture after it enters the ovule, and yet other sets of genes function in gametic fusion. Angiosperms have come long way from primitive reproductive structure development to today's sophisticated, diverse, and in most cases flamboyant organ. In this review, we will be discussing on the intricate yet complex molecular mechanism of double fertilization and how it might have been shaped by the evolutionary forces focusing particularly on the model plant Arabidopsis.
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Affiliation(s)
- Prakash B Adhikari
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Xiaoyan Liu
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Xiaoyan Wu
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Shaowei Zhu
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China
| | - Ryushiro D Kasahara
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
- Horticultural Plant Biology and Metabolomics Center (HBMC), Fujian Agriculture and Forestry University, Fuzhou, Fujian, China.
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10
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Liu X, Adhikari PB, Kasahara RD. Pollen tube contents from failed fertilization contribute to seed coat initiation in Arabidopsis. F1000Res 2019; 8:348. [PMID: 31031972 PMCID: PMC6468697 DOI: 10.12688/f1000research.18644.2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/26/2019] [Indexed: 11/20/2022] Open
Abstract
Plant seeds are essential for human beings, constituting 70% of carbohydrate resources worldwide; examples include rice, wheat, and corn. In angiosperms, fertilization of the egg by a sperm cell is required for seed formation; therefore, fertilization failure results in no seed formation, except in the special case of apomixis. Initially, plants produce many pollen grains inside the anthers; once the pollen grain is deposited onto the top of the pistil, the pollen tube elongates until it reaches the ovule. Generally, only one pollen tube is inserted into the ovule; however, we previously found that if fertilization by the first pollen tube fails, a second pollen tube could rescue fertilization via the so-called fertilization recovery system (FRS). Our previous reports also demonstrated that failed fertilization results in pollen tube-dependent ovule enlargement morphology (POEM), enlarged seeds, and partial seed coat formation if the pollen tube releases the pollen tube contents into the ovule. However, we have not determined whether all the ovules enlarge or produce seed coats if an ovule accepts the pollen tube contents. Therefore, we conducted a partial seed coat formation experiment taking into account both the FRS and POEM phenomena. Notably, the ratios of failed fertilization and the ovules with partial seed coats matched, indicating that all ovules initiate seed coat formation if the fertilization fails but the pollen tube contents enter the ovule. In addition, we confirmed that the agl62 mutant , defective in early endosperm formation, showed seed coat initiation with and without fertilization, indicating that for a normal seed coat initiation, fertilization is not required; however, for the completion of normal seed coat formation, both normal fertilization and endosperm formation are required. Further molecular evidence is required to understand these phenomena because very few factors related to FRS and POEM have been identified.
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Affiliation(s)
- Xiaoyan Liu
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,FAFU-UCR Joint Center and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Parakash Babu Adhikari
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,FAFU-UCR Joint Center and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Ryushiro D Kasahara
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China.,FAFU-UCR Joint Center and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
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11
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Zhou LZ, Dresselhaus T. Friend or foe: Signaling mechanisms during double fertilization in flowering seed plants. Curr Top Dev Biol 2018; 131:453-496. [PMID: 30612627 DOI: 10.1016/bs.ctdb.2018.11.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Since the first description of double fertilization 120 years ago, the processes of pollen tube growth and guidance, sperm cell release inside the receptive synergid cell, as well as fusion of two sperm cells to the female gametes (egg and central cell) have been well documented in many flowering plants. Especially microscopic techniques, including live cell imaging, were used to visualize these processes. Molecular as well as genetic methods were applied to identify key players involved. However, compared to the first 11 decades since its discovery, the past decade has seen a tremendous advancement in our understanding of the molecular mechanisms regulating angiosperm fertilization. Whole signaling networks were elucidated including secreted ligands, corresponding receptors, intracellular interaction partners, and further downstream signaling events involved in the cross-talk between pollen tubes and their cargo with female reproductive cells. Biochemical and structural biological approaches are now increasingly contributing to our understanding of the different signaling processes required to distinguish between compatible and incompatible interaction partners. Here, we review the current knowledge about signaling mechanisms during above processes with a focus on the model plants Arabidopsis thaliana and Zea mays (maize). The analogy that many of the identified "reproductive signaling mechanisms" also act partly or fully in defense responses and/or cell death is also discussed.
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Affiliation(s)
- Liang-Zi Zhou
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany.
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12
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Takahashi T, Honda K, Mori T, Igawa T. Loss of GCS1/HAP2 does not affect the ovule-targeting behavior of pollen tubes. PLANT REPRODUCTION 2017; 30:147-152. [PMID: 28791484 DOI: 10.1007/s00497-017-0305-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 08/02/2017] [Indexed: 06/07/2023]
Abstract
KEY MESSAGE : hap2-1 pollen tube ovule targeting. Upon pollination, a pollen grain germinates to produce a pollen tube, which grows through the style to deliver two immobile sperm cells to the female gametophyte. Double fertilization is completed after the pollen tube enters an ovule. GENERATIVE CELL SPECIFIC 1 (GCS1)/HAPLESS 2 (HAP2) contributes to the fusion of gametes at fertilization and has been suggested to affect pollen tube guidance. However, there is controversy over the role of GCS1/HAP2 in pollen tube guidance because of conflicting results from different studies. To characterize the effects of the gcs1/hap2 mutation on pollen tube behavior, we analyzed the Arabidopsis thaliana hap2-1/HAP2 mutant, which carries a gcs1/hap2 mutation in the quartet background. The quartet mutant produces tetrads consisting of four pollen grains that remain adherent after the pollen mother cell has completed meiosis. Thus, a hap2-1/HAP2 tetrad contains hap2-1 and HAP2 pollen grains in a 2:2 ratio. Moreover, the hap2-1 locus is linked to the β-glucuronidase (GUS) gene. An excess pollination experiment with hap2-1/HAP2 tetrads revealed that the hap2-1 pollen tube targets ovules normally. Additionally, the results of restricted pollination and aniline blue staining indicated that there are no significant differences between the ovule-targeting frequencies of pollen tubes from hap2-1/HAP2 and HAP2/HAP2 tetrads.
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Affiliation(s)
- Taro Takahashi
- Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba, 271-8510, Japan
| | - Ken Honda
- Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba, 271-8510, Japan
| | - Toshiyuki Mori
- Department of Tropical Medicine and Parasitology, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, Japan
| | - Tomoko Igawa
- Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba, 271-8510, Japan.
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13
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Kasahara RD, Notaguchi M, Honma Y. Discovery of pollen tube-dependent ovule enlargement morphology phenomenon, a new step in plant reproduction. Commun Integr Biol 2017. [PMCID: PMC5595410 DOI: 10.1080/19420889.2017.1338989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
In animals, when semen is discharged into the uterus, the seminal plasma carries the sperm to the egg. In plants, the function of pollen tube contents (PTC) is analogous to that of the seminal plasma in animals, i.e., carrying sperm cells to the ovules for fertilization. Because the function of the seminal plasma is essential for fertilization in animals, we propose that the function of PTC must be important for plant fertilization. To understand the function of PTC, we examined the transcriptional variation after the release of PTC into the embryo sac. The phenotypic analysis revealed that ovules were enlarged without fertilization when the PTC was released into the ovule, entirely consistent with the transcriptome analysis. We identified a new plant phenomenon, pollen tube-dependent ovule enlargement morphology (POEM) phenomenon that occurs only when the ovule accepts PTC, irrespective of fertilization. POEM is a new phase between the pollen tube guidance and fertilization phases as a reproductive step. Here we established the in vitro POEM assay, which effectively measures POEM activity. Using this assay, we identified that a simple dose of plant hormone(s) cannot induce POEM. We also showed that this assay could be a powerful tool for identifying POEM factor(s).
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Affiliation(s)
- Ryushiro D. Kasahara
- PRESTO Kasahara Sakigake Project, Japan Science and Technology Agency (JST), Furo, Chikusa, Nagoya, Aichi, Japan
- Institute of transformative bio-molecules, Nagoya University, Furo, Chikusa, Nagoya, Aichi, Japan
| | - Michitaka Notaguchi
- Graduate School of Science, Nagoya University, Furo, Chikusa, Nagoya, Aichi, Japan
- PRESTO, JST, Furo, Chikusa, Nagoya, Aichi, Japan
| | - Yujiro Honma
- PRESTO Kasahara Sakigake Project, Japan Science and Technology Agency (JST), Furo, Chikusa, Nagoya, Aichi, Japan
- Institute of transformative bio-molecules, Nagoya University, Furo, Chikusa, Nagoya, Aichi, Japan
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14
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Maruyama D, Ohtsu M, Higashiyama T. Cell fusion and nuclear fusion in plants. Semin Cell Dev Biol 2016; 60:127-135. [PMID: 27473789 DOI: 10.1016/j.semcdb.2016.07.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 10/21/2022]
Abstract
Eukaryotic cells are surrounded by a plasma membrane and have a large nucleus containing the genomic DNA, which is enclosed by a nuclear envelope consisting of the outer and inner nuclear membranes. Although these membranes maintain the identity of cells, they sometimes fuse to each other, such as to produce a zygote during sexual reproduction or to give rise to other characteristically polyploid tissues. Recent studies have demonstrated that the mechanisms of plasma membrane or nuclear membrane fusion in plants are shared to some extent with those of yeasts and animals, despite the unique features of plant cells including thick cell walls and intercellular connections. Here, we summarize the key factors in the fusion of these membranes during plant reproduction, and also focus on "non-gametic cell fusion," which was thought to be rare in plant tissue, in which each cell is separated by a cell wall.
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Affiliation(s)
- Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka-cho, Totsuka-ku, Yokohama, Kanagawa 244-0813, Japan.
| | - Mina Ohtsu
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Tetsuya Higashiyama
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan; Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan; JST ERATO Higashiyama Live-Holonics Project, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
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15
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Higashiyama T, Takeuchi H. The mechanism and key molecules involved in pollen tube guidance. ANNUAL REVIEW OF PLANT BIOLOGY 2015; 66:393-413. [PMID: 25621518 DOI: 10.1146/annurev-arplant-043014-115635] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
During sexual reproduction of flowering plants, pollen tube guidance by pistil tissue is critical for the delivery of nonmotile sperm cells to female gametes. Multistep controls of pollen tube guidance can be divided into two phases: preovular guidance and ovular guidance. During preovular guidance, various female molecules, including stimulants for pollen germination and pollen tube growth, are provided to support tube growth toward the ovary, where the ovules are located. After entering the ovary, pollen tubes receive directional cues from their respective target ovules, including attractant peptides for precise, species-preferential attraction. Successful pollen tube guidance in the pistil requires not only nutritional and directional controls but also competency controls to make pollen tubes responsive to guidance cues, regulation to terminate growth once a pollen tube arrives at the target, and strategies to stop ovular attraction depending on the fertilization of female gametes.
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16
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Heydlauff J, Groß-Hardt R. Love is a battlefield: programmed cell death during fertilization. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1323-30. [PMID: 24567492 DOI: 10.1093/jxb/eru030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Plant development and growth is sustained by the constant generation of tremendous amounts of cells, which become integrated into various types of tissues and organs. What is all too often overlooked is that this thriving life also requires the targeted degeneration of selected cells, which undergo cell death according to genetically encoded programmes or environmental stimuli. The side-by-side existence of generation and demise is particularly evident in the haploid phase of the flowering plants cycle. Here, the lifespan of terminally differentiated accessory cells contrasts with that of germ cells, which by definition live on to form the next generation. In fact, with research in recent years it is becoming increasingly clear that the gametophytes of flowering plants constitute an attractive and powerful system for investigating the molecular mechanisms underlying selective cell death.
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Affiliation(s)
- Juliane Heydlauff
- Center for Plant Molecular Biology (ZMBP), University of Tuebingen, Auf der Morgenstelle 1, D-72076 Tübingen, Germany
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17
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Rademacher S, Sprunck S. Downregulation of egg cell-secreted EC1 is accompanied with delayed gamete fusion and polytubey. PLANT SIGNALING & BEHAVIOR 2013; 8:e27377. [PMID: 24384993 DOI: 10.4161/psb.2737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
One major player known to be essential for successful gamete interactions during double fertilization in Arabidopsis thaliana is the recently identified family of egg cell-secreted EC1 proteins. Both gamete fusion events are affected in EC1-deficient female gametophytes. Here, we show that the number of ovules with unfused sperm cells is considerably higher than the number of undeveloped seeds in the same ec1-RNAi knockdown lines. We found that some sperm cells are able to fuse with the female gametes even 2 to 3 days after pollination, as reflected by delayed embryo and endosperm development, and by polytubey. We propose that the egg cell secretes EC1 proteins upon sperm arrival to promote rapid sperm activation, thereby accelerating gamete fusion and preventing polytubey.
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Affiliation(s)
- Svenja Rademacher
- Cell Biology and Plant Biochemistry; University of Regensburg; Regensburg, Germany
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry; University of Regensburg; Regensburg, Germany
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18
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Rademacher S, Sprunck S. Downregulation of egg cell-secreted EC1 is accompanied with delayed gamete fusion and polytubey. PLANT SIGNALING & BEHAVIOR 2013; 8:e27377. [PMID: 24384993 PMCID: PMC4091341 DOI: 10.4161/psb.27377] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/27/2013] [Accepted: 11/28/2013] [Indexed: 05/18/2023]
Abstract
One major player known to be essential for successful gamete interactions during double fertilization in Arabidopsis thaliana is the recently identified family of egg cell-secreted EC1 proteins. Both gamete fusion events are affected in EC1-deficient female gametophytes. Here, we show that the number of ovules with unfused sperm cells is considerably higher than the number of undeveloped seeds in the same ec1-RNAi knockdown lines. We found that some sperm cells are able to fuse with the female gametes even 2 to 3 days after pollination, as reflected by delayed embryo and endosperm development, and by polytubey. We propose that the egg cell secretes EC1 proteins upon sperm arrival to promote rapid sperm activation, thereby accelerating gamete fusion and preventing polytubey.
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