Recently, researchers from Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, cloned a key gene, FIS1, which determines fruit firmness in tomato, and revealed the regulation mechanism underlying fruit firmness mediated by gibberellin pathway. The findings have been published online in Nature Communications.

Fruit firmness is a target trait in tomato breeding because it facilitates transportation and storage. Meanwhile, it is also a complex trait affected by many factors. Thus, revealing the molecular genetic mechanisms controlling fruit firmness is still a challenge. Although several quantitative trait loci (QTLs) have been identified in tomato, none gene has been cloned to date. For the first time, researchers cloned a new gene, FIS1, associated with fruit firmness using forward genetics approach. This gene encodes a GA2- oxidase in gibberellin metabolism pathway. Mutation of FIS1 in cultivated tomatoes leads to increased bioactive gibberellin content, altered cuticle thickness, enhanced cutin and wax biosynthesis, and final results in increased fruit firmness and shelf life. In addition, disruption of FIS1 can enhance tomato fruit firmness with negligible effects on other agronomic traits such as fruit development and flavor. Therefore, this study provides new insight into the mechanism of gibberellin for fruit firmness and provides a new strategy for fruit firmness improvement in tomato breeding.

This project was supported by The National Key Research and Development Program of China, The National Natural Science Foundation of China, and the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences.

By Li Ren (liren01@caas.cn)