1. A putative positive feedback regulation mechanism in CsACS2 expression suggests a modified model for sex determination in cucumber (Cucumis sativus L.)
- Author
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Shu Wang, Longting Si, Qianyi Tao, Run Cai, Zhen-Hui Gong, Junsong Pan, and Zheng Li
- Subjects
one-hormone hypothesis ,Ethylene ,DNA, Plant ,Physiology ,Transgene ,Molecular Sequence Data ,sex determination ,Cucumis sativus L ,Gene Expression ,Flowers ,Plant Science ,Models, Biological ,ethylene induction ,chemistry.chemical_compound ,positive feedback regulation ,Organophosphorus Compounds ,Plant Growth Regulators ,Gene Expression Regulation, Plant ,Transcription (biology) ,Tobacco ,Gene expression ,Botany ,Promoter Regions, Genetic ,Gene ,Plant Proteins ,Gametogenesis, Plant ,Regulation of gene expression ,Base Sequence ,biology ,CsACS2 ,Sequence Analysis, DNA ,Ethylenes ,Plants, Genetically Modified ,biology.organism_classification ,Cell biology ,Plant Leaves ,Phenotype ,chemistry ,Seedlings ,Silver Nitrate ,Plant hormone ,Cucumis sativus ,Cucumis ,Research Paper - Abstract
It is well established that the plant hormone ethylene plays a key role in cucumber sex determination. Since the unisexual control gene M was cloned and shown to encode an ethylene synthase, instead of an ethylene receptor, the 'one-hormone hypothesis', which was used to explain the cucumber sex phenotype, has been challenged. Here, the physiological function of CsACS2 (the gene encoded by the M locus) was studied using the transgenic tobacco system. The results indicated that overexpression of CsACS2 increased ethylene production in the tobacco plant, and the native cucumber promoter had no activity in transgenic tobacco (PM). However, when PM plants were treated with exogenous ethylene, CsACS2 expression could be detected. In cucumber, ethylene treatment could also induce transcription of CsACS2, while inhibition of ethylene action reduced the expression level. These findings suggest a positive feedback regulation mechanism for CsACS2, and a modified 'one-hormone hypothesis' for sex determination in cucumber is proposed.
- Published
- 2012