Abstract: Nitrogen (N) is the mineral element with the largest demand for crops, contributing up to 40% to 50% to the final yield. There is an increasing demand for breeding high N use efficiency (NUE) cultivars using high NUE genes due to the urgent requirements for sustainable agricultural development. Here, GWAS was conducted and OsNLP6 was identified, which encodes a NIN-like protein (NLP) transcription factor, as a key regulatory gene which was highly expressed in roots for rice NUE and yield forma- tion. OsNLP6 positively regulates N uptake by activating the transcription of OsPTR2.4, which affects the nitrate transporter. The expression of this molecular module was significantly induced by low N stress. OsNLP6HapII was identified as an elite hap- lotype with high-NUE, which was mainly found in the Xian rice subgroup derived from Southeast Asia, and could enhance N uptake and effective panicle number per plant, thereby boosting rice yield and NUE. Introducing OsNLP6HapII into the Geng rice subgroup can be a potential strategy for marker-assisted selection breeding in rice. Overall, the present study highlights that the OsNLP6-OsPTR2.4 molecular module can be used to breed rice cultivars with higher NUE in order to achieve agricultural sustainability.(Plant Biotechnology Journal)
Abstract: Early postgermination growth is critical for the success of direct seeding in rice cultivation. However, the underlying mechanism determining postgermination growth of rice is largely unknown. Here, we report the rice OsDREB1A-OsNAC3-OsGA20ox1 transcriptional module that positively regulates the early postgermination growth through the gibberellic acid (GA) pathway.Transcription factor OsDREB1A improves postgermination growth by OsNAC3-mediated increase of GA biosynthesis. OsNAC3 can directly bind to the promoter of GA biosynthesis gene OsGA20ox1, which consequently activates its expression and increases GA content during the early postgermination growth stage. Fur- thermore, the expressions of OsDREB1A and OsNAC3 are positively regulated by each other, and the cis-regulatory polymorphisms in promoters fine-tune their corresponding expressions to determine the natural variations of post-germination growth. The transferred elite haplotypesofOsNAC3 and OsDREB1A and overexpression of both genes in japonica varieties contribute postgermination growth. The application of OsDREB1A and OsNAC3 is useful for the development of rice varieties for direct seeding cultivation.（Science Advances）
