Purple tomatoes with anthocyanins fulfilled in the flesh and the peel of tomato fruits by overexpressing SlAN2-like (Image by IGDB)
Anthocyanins are naturally occurring pigments responsible for the colorful appearance of plant flowers and fruits. In addition, anthocyanins are health-promoting compounds because of their high antioxidant activity. Dietary consumption of anthocyanins can reduce people’s risk of cardiovascular disease, age-related degenerative diseases and certain cancers.
Recently, the team led by Prof. LI Chuanyou at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, uncovered a number of new insights into the regulation of anthocyanin biosynthesis in tomato fruit and generated purple-fleshed tomatoes which accumulate anthocyanins in both peel and flesh.
Tomato (Solanum lycopersicum) is a favorite vegetable worldwide. Whereas the most abundant antioxidant in tomato fruit is the lipophilic lycopene, the levels of the water-soluble anthocyanins are suboptimal. Therefore, tomato is an excellent candidate for enhancement of anthocyanin content. Although most tomato cultivars do not produce anthocyanins in fruit, 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.
Researchers from LI’s lab studied the mechanisms of anthocyanin biosynthesis in Indigo Rose fruits. They cloned the genes underlying Aft and atv, and highlighted that the SlAN2-like protein, which is encoded by gene Aft in the light-exposing fruit peel, acts as a master regulator in light-induced anthocyanin biosynthesis in tomato.
Figure 1. Proposed working model for the light-induced anthocyanin biosynthesis in tomato fruit (Image by IGDB)
“We can obtain purple tomatoes with anthocyanins fulfilled in the flesh and the peel of tomato fruits by overexpressing SlAN2-like under the control of a fruit-specific promoter.” said Dr. LI. “We hope that these kinds of tomatoes might be on your plates in the future.”
Figure 2. Purple tomatoes produced by fruit-specific overexpression of SlAN2-like (Image by IGDB)
Their study uncovers the mechanisms by which light induces anthocyanin biosynthesis in tomato and provides an excellent target for enhancement of anthocyanin content by genetic manipulations.
The paper entitled “A transcriptional network promotes anthocyanin biosynthesis in tomato flesh” has been published online in
Moleluclar Plant (DOI:
10.1016/j.molp.2019.10.010).
This study was supported by grants from the Chinese Academy of Sciences, the National Key R&D Program of China, and the Ministry of Agriculture of China.
Contact:
QI Lei
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
Email: lqi@genetics.ac.cn
