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Article|01 Feb 2019|OPEN
SlMYB75, an MYB-type transcription factor, promotes anthocyanin accumulation and enhances volatile aroma production in tomato fruits
Wei Jian1 , Haohao Cao1 , Shu Yuan2 , Yudong Liu1 , Juanfang Lu3 , Wang Lu3 , Ning Li1 , Jianhui Wang4 , Jian Zou1 , Ning Tang5 , Chan Xu1 , Yulin Cheng1 , Yanqiang Gao1 , Wanpeng Xi3 , Mondher Bouzayen1,6 , Zhengguo Li,1 ,
1Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, 401331 Chongqing, China
2College of Resources, Sichuan Agricultural University, 611130 Chengdu, China
3College of Horticulture and Landscape Architecture, Southwest University, 400716 Chongqing, China
4Horticulture Institute, Sichuan Academy of Agricultural Sciences, 610066 Chengdu, China
5Institute of Special Plants, Chongqing University of Arts and Sciences, 402160 Yongchuan, China
6INRA, Genomique et Biotechnologie des Fruits, Chemin de Borde Rouge, F-31326 Castanet-Tolosan, France
*Corresponding author. E-mail: zhengguoli@cqu.edu.cn

Horticulture Research 6,
Article number: 22 (2019)
doi: https://doi.org/10.1038/s41438-018-0098-y
Views: 1228

Received: 24 May 2018
Revised: 01 Sep 2018
Accepted: 17 Sep 2018
Published online: 01 Feb 2019

Abstract

Genetic manipulation of genes to upregulate specific branches of metabolic pathways is a method that is commonly used to improve fruit quality. However, the use of a single gene to impact several metabolic pathways is difficult. Here, we show that overexpression of the single gene SlMYB75 (SlMYB75-OE) is effective at improving multiple fruit quality traits. In these engineered fruits, the anthocyanin content reached 1.86 mg g−1 fresh weight at the red-ripe stage, and these SlMYB75-OE tomatoes displayed a series of physiological changes, including delayed ripening and increased ethylene production. In addition to anthocyanin, the total contents of phenolics, flavonoids and soluble solids in SlMYB75-OE fruits were enhanced by 2.6, 4, and 1.2 times, respectively, compared to those of wild-type (WT) fruits. Interestingly, a number of aroma volatiles, such as aldehyde, phenylpropanoid-derived and terpene volatiles, were significantly increased in SlMYB75-OE fruits, with some terpene volatiles showing more than 10 times higher levels than those in WT fruits. Consistent with the metabolic assessment, transcriptomic profiling indicated that the genes involved in the ethylene signaling, phenylpropanoid and isoprenoid pathways were greatly upregulated in SlMYB75-OE fruits. Yeast one-hybrid and transactivation assays revealed that SlMYB75 is able to directly bind to the MYBPLANT and MYBPZM cis-regulatory elements and to activate the promoters of the LOXC, AADC2 and TPS genes. The identification of SlMYB75 as a key regulator of fruit quality attributes through the transcriptional regulation of downstream genes involved in several metabolic pathways opens new avenues towards engineering fruits with a higher sensory and nutritional quality.