A Transcriptional Network Promotes Anthocyanin Biosynthesis in Tomato Flesh

First author: Chuanlong Sun; Affiliations: CAS Institute of Genetics and Developmental Biology (中科院遗传与发育生物学研究所): Beijing, China

Corresponding author: Chuanyou Li

Dietary anthocyanins are important health-promoting antioxidants that make a major contribution to the quality of fruits. It is intriguing that most tomato cultivars do not produce anthocyanins in fruit. However, the purple tomato variety Indigo Rose, which combines the dominant Aft locus and the recessive atv locus from wild tomato species, exhibits light-dependent anthocyanin accumulation in the skin. Here, we report that whereas Aft encodes a functional allele of an anthocyanin activator named SlAN2-like, atv encodes a non-functional allele of the anthocyanin repressor SlMYBATV. The expression of SlAN2-like is responsive to light and a functional SlAN2-like can activate both anthocyanin biosynthetic genes and their regulatory genes, suggesting that SlAN2-like acts as a master regulator and plays a critical role for the activation of anthocyanin biosynthesis. Our results reveal that cultivated tomatoes contain a non-functional allele of this master regulator and therefore fail to produce anthocyanins. Indeed, expression of a functional SlAN2-like in a tomato cultivar led to the activation of the entire anthocyanin biosynthesis pathway and high levels of anthocyanin accumulation in both peel and flesh. Our study exemplifies that efficient engineering of complex metabolic pathways could be achieved through tissue-specific expression of master transcriptional regulators.

饮食中的花青素是重要的有益于健康的抗氧化剂，对于水果的品质非常重要。有趣的是，大多数番茄品种在它们的果实中不产生花青素。但是，紫色番茄品种“靛蓝玫瑰”结合了野生番茄品种的显性Aft基因位点和隐性atv基因位点，其果实表皮存在光依赖性的花青素积累。本文中，作者报道了Aft编码一个花青素激活因子SlAN2-like的功能性等位基因，而atv编码一个花青素抑制因子SlMYBATV的非功能性等位基因。 SlAN2-like的表达响应于光照，而功能性SlAN2-like可以同时激活花青素生物合成基因及其调节基因，这表明SlAN2-like作为一个主要调控因子，在激活花青素生物合成中发挥关键作用。作者的结果表明，栽培种番茄中含有该主调节因子的非功能性等位基因，因此无法产生花青素。确实，在番茄栽培品种中表达功能性SlAN2-like基因可导致整个花青素生物合成通路的激活以及果皮和果肉中高水平的花青素积聚。作者的研究表明，可以通过组织特异性表达主要转录调控因子来有效操控复杂的代谢通路。

通讯：李传友 (http://sourcedb.genetics.cas.cn/zw/zjrck/200907/t20090721_2130986.html)

个人简介：1991年，山东农业大学，学士；1994年，山东农业大学，硕士；1999年，中国科学院遗传研究所，博士；1999-2003年，MSU-DOE Plant Research Laboratory，博士后。

研究方向：以番茄为模式系统研究植物对昆虫抗性反应的分子机理；番茄3号染色体测序及功能基因组学研究；以拟南芥为模式研究茉莉酸与生长素互作调控植物生长发育和抗逆反应的分子机制。

doi: https://doi.org/10.1016/j.molp.2019.10.010

Journal: Molecular Plants

Published date: November 01, 2019