Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system
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Ohio University / OhioLINK
2008
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| Online Access: | http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1205379431 |
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ndltd-OhioLink-oai-etd.ohiolink.edu-ohiou12053794312021-08-03T05:45:41Z Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system Wang, Yunjing Biology Botany Molecular Biology <i> Viola pubescens </i> Violaceae chasmogamous flowers cleistogamous flowers flower development gibberellic acid <i>LEAFY</i> ABC model Plants with both open, out-crossing chasmogamous and closed, self-pollinating cleistogamous flowers are distributed over 50 angiosperm families. The chasmogamous-cleistogamous mixed breeding system is a successful reproductive strategy because it can ensure seed output over a range of environmental and pollinator conditions and maintain sexually produced progeny even in the absence of pollination agents. Many ecologists and biologists have conducted research on the mixed breeding system, but the underlying molecular mechanisms remain largely unknown. The research presented here examined the molecular biology of flower development in a widespread North American violet, <i>Viola pubescens</i>. The plant growth regulator gibberellic acid (GA) was reported to induce chasmogamous flowers from cleistogamous ones in some species. Two genes, <i>VGA20ox</i> and <i>VGA3ox</i>, which encode key enzymes (GA20 oxidase and GA3 oxidase) in the biosynthesis of GA, were identified by reverse transcriptase polymerase chain reactions (RT-PCR) from <i>V. pubescens</i>. Semi-quantitative RT-PCR indicated that both genes exhibited increased expression in chasmogamous flowers compared to cleistogamous flowers. Exogenous application of GA3, however, did not induce cleistogamous flowers to open. Thus, GA is involved in the mixed breeding system, but it is not sufficient to convert the closed status of cleistogamous flowers in <i>V. pubescens</i>. GA was demonstrated to target the floral meristem identity gene <i>LEAFY</i> (<i>LFY</i>) in <i>Arabidopsis</i>. Two <i>LFY</i> orthologs (<i>VLFY1</i> and <i>VLFY2</i>) were obtained by screening a genomic library of <i>V. pubescens</i>. Semi-quantitative RT-PCR suggested the two LFY orthologs function together in the early stages of development of both flower types. Analysis of their promoters indicated they might be differentially regulated. The ABCE floral organ identity genes come into play once the floral meristems are determined. Two A class genes (<i>VAP1</i> and <i>VAP2</i>), two B class genes (<i>VAP3</i> and <i>VPI</i>), one C class gene (<i>VAG</i>) and one E class gene (<i>VSEP3</i>) were identified by RT-PCR. The differential expression patterns of the ABCE floral genes between the chasmogamous and cleistogamous flowers were consistent with their morphological differences. Taken together, most of the floral genes examined here in <i>V. pubescens</i> were expressed differently between the two flower types, which might be a response to the different environmental conditions under which the two flower types were produced, contributing to the production of both chasmogamous and cleistogamous flowers. 2008-04-22 English text Ohio University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1205379431 http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1205379431 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws. |
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NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Biology Botany Molecular Biology <i> Viola pubescens </i> Violaceae chasmogamous flowers cleistogamous flowers flower development gibberellic acid <i>LEAFY</i> ABC model |
| spellingShingle |
Biology Botany Molecular Biology <i> Viola pubescens </i> Violaceae chasmogamous flowers cleistogamous flowers flower development gibberellic acid <i>LEAFY</i> ABC model Wang, Yunjing Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system |
| author |
Wang, Yunjing |
| author_facet |
Wang, Yunjing |
| author_sort |
Wang, Yunjing |
| title |
Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system |
| title_short |
Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system |
| title_full |
Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system |
| title_fullStr |
Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system |
| title_full_unstemmed |
Molecular biology of flower development in <i>Viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system |
| title_sort |
molecular biology of flower development in <i>viola pubescens</i>, a species with the chasmogamous-cleistogamous mixed breeding system |
| publisher |
Ohio University / OhioLINK |
| publishDate |
2008 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1205379431 |
| work_keys_str_mv |
AT wangyunjing molecularbiologyofflowerdevelopmentiniviolapubescensiaspecieswiththechasmogamouscleistogamousmixedbreedingsystem |
| _version_ |
1719424789989294080 |