Tomato transcriptional repressor MYB70 directly regulates ethylene-dependent fruit ripening
番茄转录抑制子MYB70在乙烯介导果实成熟中的作用机制
- 关键词：
- 来源：
- The Plant Journal
- 类型：
- 学术文献
- 语种：
- 英语
- 原文发布日期：
- 2020-10-13
- 摘要：
- Ethylene is a key plant hormone controlling the ripening of climacteric fruits, and a few transcription factors acting as important regulators of fruit ripening have been identified in tomato (Solanum lycopersicum), a model for climacteric fruits. However, the vast majority of them are transcriptional activators, and the associated transcriptional regulatory mechanisms of most regulators are unclear. Here, we report on a tomato transcriptional repressor (termed SlMYB70) that negatively regulates fruit ripening by directly modulating ethylene biosynthesis. As an EAR motif‐containing MYB transcription factor‐encoding gene, SlMYB70 displayed a ripening‐associated expression pattern and was responsive to ethylene. RNA interference (RNAi)‐mediated repression of SlMYB70 accelerated fruit ripening, but overexpression of SlMYB70 delayed fruit ripening. Ethylene production was noticeably increased and decreased in SlMYB70‐RNAi and SlMYB70‐overexpressing lines, respectively, compared to wild‐type tomatoes. SlMYB70 was proven to be a transcriptional repressor, dependent on the EAR repression motif, and to repress the transcription of two ethylene biosynthesis genes in fruit ripening, namely, SlACS2 and SlACO3. The promoters of SlACS2 and SlACO3 are directly bound by SlMYB70, which was verified by using a combination of yeast one‐hybrid, chromatin immunoprecipitation‐qPCR, and electrophoretic mobility shift assays. These results suggest that SlMYB70 negatively regulates fruit ripening via direct transcriptional repression of ethylene biosynthesis genes, which provides insights into the ethylene‐mediated key regulatory hierarchy in climacteric fruit ripening and also highlights different types of transcriptional regulation of fruit ripening.
- 所属专题：
- 128
