Key gene controlling heterosis in tomatoes identified
A team of US and Israeli researchers, from Cold Springs Harbor Laboratory in the US and the Hebrew University of Jerusalem, has identified a key gene involved in the phenomenon of heterosis (hybrid vigour) that increases yield and sweetness in tomato hybrids. The researchers, from Cold Springs Harbor Laboratory (CSHL) in the US and the Hebrew University of Jerusalem, found that a single “overdominant” gene, dubbed single flower truss (SFT), controls flowering time and hence yields, as well as sugar distribution, in fruits. SFT regulates expression of the protein, florigen, which promotes flowering. It suppresses another gene, self pruning (SP), which delays flowering and checks growth. Plants carrying one copy of a mutant loss-of-function allele of SFT showed yield increases of up to 60%. The accompanying unexpected increase in sugar content of SFT mutant tomato fruits is due to the pleitropic interaction of the two genes, SFT and SP, affecting other metabolic pathways.