1. A SlMYB75-centred transcriptional cascade regulates trichome formation and sesquiterpene accumulation in tomato.
- Author
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Gong, Zehao, Luo, Yingqing, Zhang, Wenfa, Jian, Wei, Zhang, Lu, Gao, Xueli, Hu, Xiaowei, Yuan, Yujin, Wu, Mengbo, Xu, Xin, Zheng, Xianzhe, Wu, Guanle, Li, Zhengguo, Li, Zhi, and Deng, Wei
- Subjects
MYB gene ,SPIDER mites ,TRANSCRIPTION factors ,TOMATOES ,TRICHOMES ,CARYOPHYLLENE - Abstract
Tomato trichomes act as a mechanical and chemical barrier against pests. An R2R3 MYB transcription factor gene, SlMYB75 , is highly expressed in type II, V, and VI trichomes. SlMYB75 protein is located in the nucleus and possesses transcriptional activation activity. Down-regulation of SlMYB75 increased the formation of type II, V, and VI trichomes, accumulation of δ-elemene, β-caryophyllene, and α-humulene in glandular trichomes, and tolerance to spider mites in tomato. In contrast, overexpression of SlMYB75 inhibited trichome formation and sesquiterpene accumulation, and increased plant sensitivity to spider mites. RNA-Seq analyses of the SlMYB75 RNAi line indicated massive perturbation of the transcriptome, with a significant impact on several classes of transcription factors. Expression of the MYB genes SlMYB52 and SlTHM1 was strongly reduced in the RNAi line and increased in the SlMYB75- overexpressing line. SlMYB75 protein interacted with SlMYB52 and SlTHM1 and activated their expression. SlMYB75 directly targeted the promoter of the cyclin gene SlCycB2 , increasing its activity. The auxin response factor SlARF4 directly targeted the promoter of SlMYB75 and inhibited its expression. SlMYB75 also bound to the promoters of the terpene synthase genes SlTPS12 , SlTPS31 , and SlTPS35 , inhibiting their transcription. Our findings indicate that SlMYB75 perturbation affects several transcriptional circuits, resulting in altered trichome density and metabolic content. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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