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Zhao L, Zhou W, He J, Li DZ, Li HT. Positive selection and relaxed purifying selection contribute to rapid evolution of male-biased genes in a dioecious flowering plant. eLife 2024; 12:RP89941. [PMID: 38353667 PMCID: PMC10942601 DOI: 10.7554/elife.89941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024] Open
Abstract
Sex-biased genes offer insights into the evolution of sexual dimorphism. Sex-biased genes, especially those with male bias, show elevated evolutionary rates of protein sequences driven by positive selection and relaxed purifying selection in animals. Although rapid sequence evolution of sex-biased genes and evolutionary forces have been investigated in animals and brown algae, less is known about evolutionary forces in dioecious angiosperms. In this study, we separately compared the expression of sex-biased genes between female and male floral buds and between female and male flowers at anthesis in dioecious Trichosanthes pilosa (Cucurbitaceae). In floral buds, sex-biased gene expression was pervasive, and had significantly different roles in sexual dimorphism such as physiology. We observed higher rates of sequence evolution for male-biased genes in floral buds compared to female-biased and unbiased genes. Male-biased genes under positive selection were mainly associated with functions to abiotic stress and immune responses, suggesting that high evolutionary rates are driven by adaptive evolution. Additionally, relaxed purifying selection may contribute to accelerated evolution in male-biased genes generated by gene duplication. Our findings, for the first time in angiosperms, suggest evident rapid evolution of male-biased genes, advance our understanding of the patterns and forces driving the evolution of sexual dimorphism in dioecious plants.
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Affiliation(s)
- Lei Zhao
- Germplasm Bank of Wild Species & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of SciencesKunming, YunnanChina
| | - Wei Zhou
- Germplasm Bank of Wild Species & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of SciencesKunming, YunnanChina
| | - Jun He
- Germplasm Bank of Wild Species & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of SciencesKunming, YunnanChina
| | - De-Zhu Li
- Germplasm Bank of Wild Species & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of SciencesKunming, YunnanChina
- Kunming College of Life Science, University of Chinese Academy of SciencesKunmingChina
| | - Hong-Tao Li
- Germplasm Bank of Wild Species & Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of SciencesKunming, YunnanChina
- Kunming College of Life Science, University of Chinese Academy of SciencesKunmingChina
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2
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Kazama Y, Kitoh M, Kobayashi T, Ishii K, Krasovec M, Yasui Y, Abe T, Kawano S, Filatov DA. A CLAVATA3-like Gene Acts as a Gynoecium Suppression Function in White Campion. Mol Biol Evol 2022; 39:msac195. [PMID: 36166820 PMCID: PMC9550985 DOI: 10.1093/molbev/msac195] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
How do separate sexes originate and evolve? Plants provide many opportunities to address this question as they have diverse mating systems and separate sexes (dioecy) that evolved many times independently. The classic "two-factor" model for evolution of separate sexes proposes that males and females can evolve from hermaphrodites via the spread of male and female sterility mutations that turn hermaphrodites into females and males, respectively. This widely accepted model was inspired by early genetic work in dioecious white campion (Silene latifolia) that revealed the presence of two sex-determining factors on the Y-chromosome, though the actual genes remained unknown. Here, we report identification and functional analysis of the putative sex-determining gene in S. latifolia, corresponding to the gynoecium suppression factor (GSF). We demonstrate that GSF likely corresponds to a Y-linked CLV3-like gene that is specifically expressed in early male flower buds and encodes the protein that suppresses gynoecium development in S. latifolia. Interestingly, GSFY has a dysfunctional X-linked homolog (GSFX) and their synonymous divergence (dS = 17.9%) is consistent with the age of sex chromosomes in this species. We propose that female development in S. latifolia is controlled via the WUSCHEL-CLAVATA feedback loop, with the X-linked WUSCHEL-like and Y-linked CLV3-like genes, respectively. Evolution of dioecy in the S. latifolia ancestor likely involved inclusion of ancestral GSFY into the nonrecombining region on the nascent Y-chromosome and GSFX loss of function, which resulted in disbalance of the WUSCHEL-CLAVATA feedback loop between the sexes and ensured gynoecium suppression in males.
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Affiliation(s)
- Yusuke Kazama
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-cho, Japan
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Moe Kitoh
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-cho, Japan
| | - Taiki Kobayashi
- Graduate School of Bioscience and Biotechnology, Fukui Prefectural University, 4-1-1 Kenjojima, Matsuoka, Eiheiji-cho, Japan
| | - Kotaro Ishii
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- National Institutes for Quantum and Radiological Science and Technology, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Marc Krasovec
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
- Sorbonne Université, CNRS, UMR 7232 Biologie Intégrative des Organismes Marins (BIOM), Observatoire Océanologique, 66650 Banyuls-sur-Mer, France
| | - Yasuo Yasui
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Tomoko Abe
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Shigeyuki Kawano
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, FSB-601, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
- Future Center Initiative, The University of Tokyo, 178-4-4 Wakashiba, Kashiwa, Chiba 277-0871, Japan
| | - Dmitry A Filatov
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
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3
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Rodriguez-Granados NY, Ramirez-Prado JS, Brik-Chaouche R, An J, Manza-Mianza D, Sircar S, Troadec C, Hanique M, Soulard C, Costa R, Dogimont C, Latrasse D, Raynaud C, Boualem A, Benhamed M, Bendahmane A. CmLHP1 proteins play a key role in plant development and sex determination in melon (Cucumis melo). THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:1213-1228. [PMID: 34897855 DOI: 10.1111/tpj.15627] [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: 05/04/2021] [Revised: 11/26/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
In monoecious melon (Cucumis melo), sex is determined by the differential expression of sex determination genes (SDGs) and adoption of sex-specific transcriptional programs. Histone modifications such as H3K27me3 have been previously shown to be a hallmark associated to unisexual flower development in melon; yet, no genetic approaches have been conducted for elucidating the roles of H3K27me3 writers, readers, and erasers in this process. Here we show that melon homologs to Arabidopsis LHP1, CmLHP1A and B, redundantly control several aspects of plant development, including sex expression. Cmlhp1ab double mutants displayed an overall loss and redistribution of H3K27me3, leading to a deregulation of genes involved in hormone responses, plant architecture, and flower development. Consequently, double mutants display pleiotropic phenotypes and, interestingly, a general increase of the male:female ratio. We associated this phenomenon with a general deregulation of some hormonal response genes and a local activation of male-promoting SDGs and MADS-box transcription factors. Altogether, these results reveal a novel function for CmLHP1 proteins in maintenance of monoecy and provide novel insights into the polycomb-mediated epigenomic regulation of sex lability in plants.
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Affiliation(s)
- Natalia Yaneth Rodriguez-Granados
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Juan Sebastian Ramirez-Prado
- Centre of Microbial and Plant Genetics, KU Leuven, 3001, Leuven, Belgium
- VIB Center for Plant Systems Biology, 9052, Ghent, Belgium
| | - Rim Brik-Chaouche
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Jing An
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Deborah Manza-Mianza
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Sanchari Sircar
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Christelle Troadec
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Melissa Hanique
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Camille Soulard
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Rafael Costa
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Catherine Dogimont
- INRA, UR 1052, Unité de Génétique et d'Amélioration des Fruits et Légumes, BP 94, F-84143, Montfavet, France
| | - David Latrasse
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Cécile Raynaud
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Adnane Boualem
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Moussa Benhamed
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
| | - Abdelhafid Bendahmane
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, University Paris-Sud, University of Evry, University Paris-Diderot, Sorbonne Paris-Cite, University of Paris-Saclay, Batiment, 630, 91405, Orsay, France
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4
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Zhang H, Li S, Yang L, Cai G, Chen H, Gao D, Lin T, Cui Q, Wang D, Li Z, Cai R, Bai S, Lucas WJ, Huang S, Zhang Z, Sun J. Gain-of-function of the 1-aminocyclopropane-1-carboxylate synthase gene ACS1G induces female flower development in cucumber gynoecy. THE PLANT CELL 2021; 33:306-321. [PMID: 33793793 PMCID: PMC8136878 DOI: 10.1093/plcell/koaa018] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 11/03/2020] [Indexed: 05/06/2023]
Abstract
Unisexual flowers provide a useful system for studying plant sex determination. In cucumber (Cucumis sativus L.), three major Mendelian loci control unisexual flower development, Female (F), androecious [a; 1-aminocyclopropane-1-carboxylate {ACC} synthase 11, acs11], and Monoecious (M; ACS2), referred to here as the Female, Androecious, Monoecious (FAM) model, in combination with two genes, gynoecious (g, the WIP family C2H2 zinc finger transcription factor gene WIP1) and the ethylene biosynthetic gene ACC oxidase 2 (ACO2). The F locus, conferring gynoecy and the potential for increasing fruit yield, is defined by a 30.2-kb tandem duplication containing three genes. However, the gene that determines the Female phenotype, and its mechanism, remains unknown. Here, we created a set of mutants and revealed that ACS1G is responsible for gynoecy conferred by the F locus. The duplication resulted in ACS1G acquiring a new promoter and expression pattern; in plants carrying the F locus duplication, ACS1G is expressed early in floral bud development, where it functions with ACO2 to generate an ethylene burst. The resulting ethylene represses WIP1 and activates ACS2 to initiate gynoecy. This early ACS1G expression bypasses the need for ACS11 to produce ethylene, thereby establishing a dominant pathway for female floral development. Based on these findings, we propose a model for how these ethylene biosynthesis genes cooperate to control unisexual flower development in cucumber.
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Affiliation(s)
- Huimin Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences,
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry
of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics,
Beijing 100081, China
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural
Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences,
Shenzhen 518124, China
| | - Shuai Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences,
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry
of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics,
Beijing 100081, China
| | - Li Yang
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural
Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences,
Shenzhen 518124, China
- College of Horticulture and Forestry, Huazhong Agricultural University and Key
Laboratory of Horticultural Plant Biology, Ministry of Education, Wuhan
430070, China
| | - Guanghua Cai
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural
Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences,
Shenzhen 518124, China
| | - Huiming Chen
- Hunan Vegetable Research Institute, Hunan Academy of Agricultural
Science, Changsha 410125, China
| | - Dongli Gao
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural
Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences,
Shenzhen 518124, China
| | - Tao Lin
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural
Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences,
Shenzhen 518124, China
| | - Qingzhi Cui
- Hunan Vegetable Research Institute, Hunan Academy of Agricultural
Science, Changsha 410125, China
| | - Donghui Wang
- College of Life Sciences, Peking University, Beijing 100871,
China
| | - Zheng Li
- College of Horticulture, Northwest A&F University, Shaanxi
712100, China
| | - Run Cai
- School of Agriculture and Biology, Shanghai Jiao Tong University,
Shanghai 200240, China
| | - Shunong Bai
- College of Life Sciences, Peking University, Beijing 100871,
China
| | - William J Lucas
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural
Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences,
Shenzhen 518124, China
- College of Biological Sciences, University of California, Davis,
CA 95616, USA
| | - Sanwen Huang
- Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural
Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences,
Shenzhen 518124, China
| | - Zhonghua Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences,
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry
of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics,
Beijing 100081, China
- College of Horticulture, Qingdao Agricultural University, Qingdao
266109, China
| | - Jinjing Sun
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences,
Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry
of Agriculture, Sino-Dutch Joint Laboratory of Horticultural Genomics,
Beijing 100081, China
- Authors for correspondence: ,
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5
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Pan J, Wen H, Chen G, Lin WH, Du H, Chen Y, Zhang L, Lian H, Wang G, Cai R, Pan J. A Positive Feedback Loop Mediated by CsERF31 Initiates Female Cucumber Flower Development: ETHYLENE RESPONSE FACTOR31 mediates a positive feedback loop that initiates female cucumber flower development. PLANT PHYSIOLOGY 2021; 186:kiab141. [PMID: 33744968 PMCID: PMC8195516 DOI: 10.1093/plphys/kiab141] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/05/2021] [Indexed: 05/24/2023]
Abstract
Sex determination is a crucially important developmental event that is pervasive throughout nature and enhances the adaptation of species. Among plants, cucumber (Cucumis sativus L.) can generate both unisexual and bisexual flowers, and the sex type is mainly controlled by several 1-aminocyclopropane-1-carboxylic acid (ACC) synthases. However, the regulatory mechanism of these synthases remains elusive. Here, we used gene expression analysis, protein-DNA interaction assays and transgenic plants to study the function of a gynoecium-specific gene, ETHYLENE RESPONSE FACTOR31 (CsERF31), in female flower differentiation. We found that in a predetermined female flower, ethylene signalling activates CsERF31 by CsEIN3, and then CsERF31 stimulates CsACS2, which triggers a positive feedback loop to ensure female rather than bisexual flower development. A similar interplay is functionally conserved in melon (Cucumis melo L.). Knockdown of CsERF31 by RNAi causes defective bisexual flowers to replace female flowers. Ectopic expression of CsERF31 suppresses stamen development and promotes pistil development in male flowers, demonstrating that CsERF31 functions as a sex switch. Taken together, our data confirm that CsERF31 represents the molecular link between female-male determination and female-bisexual determination, and provide mechanistic insight into how ethylene promotes female flowers, rather than bisexual flowers, in cucumber sex determination.
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Affiliation(s)
- Jian Pan
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Haifan Wen
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Guanqun Chen
- School of Design, Shanghai Jiao Tong University, Shanghai, China
| | - Wen-Hui Lin
- School of Life Sciences and Biotechnology, The Joint International Research Laboratory of Metabolic and Developmental Sciences, Joint Center for Single Cell Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Hui Du
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yue Chen
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Leyu Zhang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Hongli Lian
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Gang Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Run Cai
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Junsong Pan
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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6
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Li D, Sheng Y, Niu H, Li Z. Gene Interactions Regulating Sex Determination in Cucurbits. FRONTIERS IN PLANT SCIENCE 2019; 10:1231. [PMID: 31649699 PMCID: PMC6796545 DOI: 10.3389/fpls.2019.01231] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 09/05/2019] [Indexed: 05/13/2023]
Abstract
The family Cucurbitaceae includes many economically important crops, such as cucumber (Cucumis sativus), melon (Cucumis melo), watermelon (Citrullus lanatus), and zucchini (Cucurbita pepo), which share homologous gene pathways that control similar phenotypes. Sex determination is a research hotspot associated with yield and quality, and the genes involved are highly orthologous and conserved in cucurbits. In the field, six normal sex types have been categorized according to the distribution of female, male, or bisexual flowers in a given plant. To date, five orthologous genes involved in sex determination have been cloned, and their various combinations and expression patterns can explain all the identified sex types. In addition to genetic mechanisms, ethylene controls sex expression in this family. Two ethylene signaling components have been identified recently, which will help us to explore the ethylene signaling-mediated interactions among sex-related genes. This review discusses recent advances relating to the mechanism of sex determination in cucurbits and the prospects for research in this area.
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Affiliation(s)
- Dandan Li
- College of Horticulture and Landscape Architecture, Heilongjiang Bayi Agriculture University, Daqing, China
| | - Yunyan Sheng
- College of Horticulture and Landscape Architecture, Heilongjiang Bayi Agriculture University, Daqing, China
| | - Huanhuan Niu
- College of Horticulture, Northwest A&F University, Yangling, China
| | - Zheng Li
- College of Horticulture, Northwest A&F University, Yangling, China
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7
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West NW, Golenberg EM. Gender-specific expression of GIBBERELLIC ACID INSENSITIVE is critical for unisexual organ initiation in dioecious Spinacia oleracea. THE NEW PHYTOLOGIST 2018; 217:1322-1334. [PMID: 29226967 DOI: 10.1111/nph.14919] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/20/2017] [Indexed: 05/20/2023]
Abstract
While unisexual flowers have evolved repeatedly throughout angiosperm families, the actual identification of sex-determining genes has been elusive, and their regulation within populations remains largely undefined. Here, we tested the mechanism of the feminization pathway in cultivated spinach (Spinacia oleracea), and investigated how this pathway may regulate alternative sexual development. We tested the effect of gibberellic acid (GA) on sex determination through exogenous applications of GA and inhibitors of GA synthesis and proteasome activity. GA concentrations in multiple tissues were estimated by enzyme-linked immunosorbent assay analysis. Gene function was investigated and pathway analysis was performed through virus-induced gene silencing. Relative gene expression levels were estimated by quantitative reverse transcription-polymerase chain reaction. Inhibition of GA production and proteasome activity feminized male flowers. However, there was no difference in GA content in tissues between males and females. We characterized a single DELLA family transcription factor gene (GIBBERELLIC ACID INSENSITIVE (SpGAI)) and observed inflorescence expression in females two-fold higher than in males. Reduction of SpGAI expression in females to male levels phenocopied exogenous GA application with respect to flower development. These results implicate SpGAI as the feminizing factor in spinach, and suggest that the feminizing pathway is epistatic to the masculinizing pathway. We present a unified model for alternative sexual development and discuss the implications for established theory.
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Affiliation(s)
- Nicholas W West
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
| | - Edward M Golenberg
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
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8
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9
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Käfer J, Marais GAB, Pannell JR. On the rarity of dioecy in flowering plants. Mol Ecol 2017; 26:1225-1241. [PMID: 28101895 DOI: 10.1111/mec.14020] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 12/27/2016] [Accepted: 12/28/2016] [Indexed: 01/21/2023]
Abstract
Dioecy, the coexistence of separate male and female individuals in a population, is a rare but phylogenetically widespread sexual system in flowering plants. While research has concentrated on why and how dioecy evolves from hermaphroditism, the question of why dioecy is rare, despite repeated transitions to it, has received much less attention. Previous phylogenetic and theoretical studies have suggested that dioecy might be an evolutionary dead end. However, recent research indicates that the phylogenetic support for this hypothesis is attributable to a methodological bias and that there is no evidence for reduced diversification in dioecious angiosperms. The relative rarity of dioecy thus remains a puzzle. Here, we review evidence for the hypothesis that dioecy might be rare not because it is an evolutionary dead end, but rather because it easily reverts to hermaphroditism. We review what is known about transitions between hermaphroditism and dioecy, and conclude that there is an important need to consider more widely the possibility of transitions away from dioecy, both from an empirical and a theoretical point of view, and by combining tools from molecular evolution and insights from ecology.
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Affiliation(s)
- Jos Käfer
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Lyon 1, Bât. Grégor Mendel 43, bd du 11 novembre 1918, 69622, Villeurbanne cedex, France
| | - Gabriel A B Marais
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université Lyon 1, Bât. Grégor Mendel 43, bd du 11 novembre 1918, 69622, Villeurbanne cedex, France
| | - John R Pannell
- Department of Ecology and Evolution, University of Lausanne, Biophore Building, 1015, Lausanne, Switzerland
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