Development and application of functional marker for high nitrogen use efficiency and chilling tolerance gene OsGRF4 in rice

Abstract

The use of molecular marker-assisted selection (MAS) to breed rice with high nitrogen-use efficiency is one of the most effective methods to reduce the amount of nitrogen fertilizer quantity and to develop the green and sustainable agriculture. The gene growth-regulating factor 4 (OsGRF4) encodes a growth regulatory factor protein, and the mutation in the coding region from the nucleotides TC to AA in 487 and 488 substituted the amino acid serine for lysine, which resulting in enhancing nitrogen-use efficiency, increasing grain yield, and improving chilling tolerance in rice. In order to improve the selection efficiency of OsGRF4 in rice breeding, an allele-specific PCR (AS-PCR) marker combination, PF+DMR+PR and PF+XMR+PR, was developed based on the single nucleotide polymorphism in the functional region of the OsGRF4 alleles. The functional marker was used to identify genotypes of different varieties and an F2 population derived from Chuandali/Jusuidao. The three different genotypes of OsGRF4 locus could be accurately distinguished, which was further confirmed by sequencing. This functional marker is simple to operate and low-cost, and could provide a technical support when using MAS to breed new rice varieties of high nitrogen-use efficiency, high yields, and increased chilling tolerance.