Identification and fine mapping of a major QTL, qHD19, that plays pleiotropic roles in regulating the heading date in rice

Abstract

As a food consumed by more than half of the world’s population, rice (Oryza sativa) has always been a hot spot in plant science research. The three most important agronomic traits of rice, the yield, plant height, and flowering time, are controlled by many quantitative trait locus (QTLs). In this study, a newly identified QTL, qHD19, was found to be controlled by a single recessive gene. Using two populations with chromosome segment substitutions, qHD19 was narrowed to a 22.5-kb region containing three putative genes, one of which encoded a ZOS5-02-C2H2 zinc finger protein. This gene was regarded as the qHD19 candidate. Further analysis showed that the amino acid sequence encoded by the qHD19 gene included two amino acid mutations, (84): lysine (L) replaced by phenylalanine (F), and (169): alanine (A) replaced valine (V), and these mutations are expected to significantly alter the functions of the protein. Additionally, the CSSL87 and CSSL88 lines containing the qHD19 gene not only exhibited a shorter plant height but also exhibited a higher yield, which showed that the qHD19 gene presents good application prospects in rice breeding. Taken together, these data indicate that qHD19 probably plays an important role in the signaling network of photoperiodic flowering as well as the regulation of plant height and yield potential.