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Article|01 Jul 2021|OPEN
SlBBX20 interacts with the COP9 signalosome subunit SlCSN5-2 to regulate anthocyanin biosynthesis by activating SlDFR expression in tomato
Dan Luo1, Cheng Xiong1, Aihua Lin1, Chunli Zhang1, Wenhui Sun1, Junhong Zhang1, Changxian Yang1, Yongen Lu1, Hanxia Li1, Zhibiao Ye1, Ping He2 & Taotao Wang1,
1Key Laboratory of Horticulture Plant Biology, Ministry of Education, Huazhong Agriculture University, 430070 Wuhan, China
2Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA

Horticulture Research 8,
Article number: 163 (2021)
doi: 10.1038/hortres.2021.163
Views: 169

Received: 27 Oct 2020
Revised: 24 Mar 2021
Accepted: 19 Apr 2021
Published online: 01 Jul 2021

Abstract

Anthocyanins play vital roles in plant stress tolerance and growth regulation. Previously, we reported that the photomorphogenesis-related transcription factor SlBBX20 regulates anthocyanin accumulation in tomato. However, the underlying mechanism remains unclear. Here, we showed that SlBBX20 promotes anthocyanin biosynthesis by binding the promoter of the anthocyanin biosynthesis gene SlDFR, suggesting that SlBBX20 directly activates anthocyanin biosynthesis genes. Furthermore, we found by yeast two-hybrid screening that SlBBX20 interacts with the COP9 signalosome subunit SlCSN5-2, and the interaction was confirmed by bimolecular fluorescence complementation and coimmunoprecipitation assays. SlCSN5 gene silencing led to anthocyanin hyperaccumulation in the transgenic tomato calli and shoots, and SlCSN5-2 overexpression decreased anthocyanin accumulation, suggesting thSlCSN5-2 enhanced the ubiquitination of SlBBX20 and promoted the degradation of SlBBX20 in vivo. Consistently, silencing the SlCSN5-2 homolog in tobacco significantly increased the accumulation of the SlBBX20 protein. Since SlBBX20 is a vital regulator of photomorphogenesis, the SlBBX20-SlCSN5-2 module may represent a novel regulatory pathway in light-induced anthocyanin biosynthesis.