The Ghd7 transcription factor represses ARE1 expression to enhance nitrogen utilization and grain yield in rice

Abstract

The genetic improvement of nitrogen use efficiency (NUE) of crops is vital for grain productivity and sustainable agriculture. However, the regulatory mechanism of NUE remains largely elusive. Here, we report that the rice Grain number, plant height, and heading date7 (Ghd7) gene genetically acts upstream of ABC1 REPRESSOR1 (ARE1), a negative regulator of NUE, to positively regulate nitrogen utilization. As a transcriptional repressor, Ghd7 directly binds to two Evening Element-like motifs in the promoter and intron 1 of ARE1, likely in a cooperative manner, to repress its expression. Ghd7 and ARE1 display diurnal expression patterns in an inverse oscillation manner, mirroring a regulatory scheme based on these two loci. Analysis of a panel of 2656 rice varieties suggests that the elite alleles of Ghd7 and ARE1 have undergone diversifying selection during breeding. Moreover, the allelic distribution of Ghd7 and ARE1 is associated with the soil nitrogen deposition rate in East Asia and South Asia. Remarkably, the combination of the Ghd7 and ARE1 elite alleles substantially improves NUE and yield performance under nitrogen-limiting conditions. Collectively, these results define a Ghd7-ARE1-based regulatory mechanism of nitrogen utilization, providing useful targets for genetic improvement of rice NUE.

Molecular Hydrogen Increases Quantitative and Qualitative Traits of Rice Grain in Field Trials

“…The following are available online at https://www.mdpi.com/article/10 .3390/plants10112331/s1, Table S1: The sequences of primers for qPCR, References [65][66][67][68][69][70][71][72][73][74][75] are cited in the Supplementary Materials.…”

Loci and Natural Alleles for Low-Nitrogen-Induced Growth Response Revealed by the Genome-Wide Association Study Analysis in Rice (Oryza sativa L.)

“…Notably, ARE1 (for abc1 PEPRESSOR1) is prominent due to its enhanced NUE under nitrogen-limiting conditions (Wang et al, 2018a). Subsequently, grain number, plant height, and heading date7 (Ghd7) confer tolerance to LN, in order to positively regulate nitrogen utilization (Good et al, 2004;Saito et al, 2019;Wang et al, 2021). Additionally, the allelic variation in OsNR2 (Gao Z. et al, 2019) caused differences in the NO 3 − assimilation capacity and NUE of the indica and japonica subspecies.…”

Rice functional genomics: decades’ efforts and roads ahead

“…Genes regulating rice heading date have also been revealed to participate in N signaling and metabolism (Fang et al, 2019;Wang et al, 2021c). Grain number, plant height and heading date7 (Ghd7) encoding a CCT-domain transcription factor has been reported to negatively regulate heading date and drought resistance, while positively regulate plant height and panicle size (Weng et al, 2014;Xue et al, 2008).…”

“…Grain number, plant height and heading date7 (Ghd7) encoding a CCT-domain transcription factor has been reported to negatively regulate heading date and drought resistance, while positively regulate plant height and panicle size (Weng et al, 2014;Xue et al, 2008). It was recently reported that Ghd7 can directly repress the expression of ARE1, which encodes a negative regulator of NUE and heading date (Wang et al, 2018d), thereby promoting nitrogen utilization (Wang et al, 2021c). Although the Ghd7-ARE1 module in enhancing NUE is concomitant with delayed heading date, they provide a possible solution for improving NUE with different geographical fitness.…”