Narrowing down a major QTL region reveals () as the candidate gene controlling flowering time in mungbean ().

Flowering time is an important agronomic trait that is highly correlated with plant height, maturity time and yield in mungbean. Up to present, however, molecular basis of flowering time in mungbean is poorly understood. Previous studies demonstrated that flowering time in mungbean is largely controlled by a major QTL on linkage group 2 (LG2). In this study, the QTL on the LG2 in mungbean was investigated using F and F populations derived from a cross between mungbean cultivar Kamphaeng Saen 2 (KPS2) and wild mungbean accession ACC41. The QTL was narrowed down to a genome region of 164.87 Kb containing a phytochrome gene, designated , encoding phytochrome E (phyE), a known photoreceptor modulating flowering time. Compared to of the wild ACC41, of KPS2 contained several single nucleotide polymorphisms (SNPs) causing amino acid changes. Those SNPs were also found in other mungbean cultivars. Some amino acid changes were predicted to occur in the regulatory region of phytochromes. Gene expression analysis revealed that in KPS2 was expressed significantly higher than that in ACC41. These results showed that is the candidate gene controlling flowering time in the mungbean.