A fruit ripening-associated transcription factor CsMADS5 positively regulates carotenoid biosynthesis in citrus

第一作者：Suwen Lu

第一单位：华中农业大学

通讯作者：Xiuxin Deng

 Abstract 

背景+问题：Carotenoids in citrus contribute the quality of the fruit, but the transcriptional regulatory mechanism is still limitedly known. 

主要研究：Here, we characterized a citrus FUL-like MADS gene, CsMADS5, that was ripening-inducible and acted as a nucleus-localized trans-activator.

结果1-瞬间表达：Transient overexpression of CsMADS5 in citrus induced fruit coloration and enhanced carotenoid contents. The expression levels of carotenogenic genes including phytoene synthase (PSY), phytoene desaturase (PDS), and lycopene β-cyclase 1 (LCYb1) were significantly increased in the peel of fruits overexpressing CsMADS5.

结果2-稳定表达：Similar results were observed from stable overexpression of CsMADS5 in tomato fruits and citrus calli, even though the effect of CsMADS5 on the carotenoid metabolism in transgenic citrus calli was limited.

结果3-下游验证：Further biochemical analyses demonstrated that CsMADS5 activated the transcription of PSY, PDS, and LCYb1 by directly binding to their promoters. It is concluded that CsMADS5 positively regulates carotenoid biosynthesis in fruits by directly activating the transcription of carotenogenic genes.

结果4-互作蛋白：Moreover, CsMADS5 physically interacted with a positive regulator CsMADS6, indicating that CsMADS5 may form an enhancer complex with CsMADS6 to synergistically promote carotenoid accumulation.

结论：These findings expand our understanding of the complex transcriptional regulatory hierarchy for carotenoid biosynthesis during fruit ripening.

doi: https://doi.org/10.1093/jxb/erab045

Journal: Journal of Experimental Botany

Published date: Feb 05, 2021