A banana R2R3-MYB transcription factor MaMYB3 is involved
A banana R2R3-MYB transcription factor MaMYB3 is involved
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DOI：
10.1111/tpj.14099
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Chen JY
中科院分区：
文献类型：
--
作者：
Fan ZQ;Ba LJ;Shan W;Xiao YY;Lu WJ;Kuang JF;Chen JY
Starch degradation is a necessary process determining banana fruit quality during ripening. Many starch.degradation-related genes are well studied. However, the transcriptional regulation of starch degradation.during banana fruit ripening remains poorly understood. In this study, we identified a MYB transcription factor.(TF) termed MaMYB3, as a putative protein binding the promoter of MaGWD1, a member of glucan.water dikinase (GWD) family which has been demonstrated as an important enzyme of starch degradation..MaMYB3 was ripening- and ethylene-repressible, and its expression was negatively correlated with starch.degradation. Acting as a nucleus-localized transcriptional repressor, MaMYB3 repressed the transcription of.10 starch degradation-related genes, including MaGWD1, MaSEX4, MaBAM7-MaBAM8, MaAMY2B,.MaAMY3, MaAMY3A, MaAMY3C, MaMEX1, and MapGlcT2-1, by directly binding to their promoters. Interestingly,.a previously identified activator of starch degradation-related genes, MabHLH6, was also suppressed.by MaMYB3. The ectopic overexpression of MaMYB3 in tomato down-regulated the expression of.starch degradation-related genes, inhibited starch degradation and delayed fruit ripening. Based on these.findings, we conclude that MaMYB3 negatively impacts starch degradation by directly repressing starch.degradation-related genes and MabHLH6, and thereby delays banana fruit ripening. Collectively, our study.expands our understanding of the complex transcriptional regulatory hierarchy modulating starch degradation.during fruit ripening.
