Natural allelic variation in a modulator of auxin homeostasis improves grain yield and nitrogen use efficiency in rice

Abstract

The external application of nitrogen (N) fertilizers is an important practice for increasing crop production. However, the excessive use of fertilizers significantly increases production costs and causes environmental problems, making the improvement of crop N-use efficiency (NUE) crucial for sustainable agriculture in the future. Here we show that the rice (Oryza sativa) NUE quantitative trait locus DULL NITROGEN RESPONSE1 (qDNR1), which is involved in auxin homeostasis, reflects the differences in nitrate (NO3−) uptake, N assimilation, and yield enhancement between indica and japonica rice varieties. Rice plants carrying the DNR1indica allele exhibit reduced N-responsive transcription and protein abundance of DNR1. This, in turn, promotes auxin biosynthesis, thereby inducing AUXIN RESPONSE FACTOR-mediated activation of NO3− transporter and N-metabolism genes, resulting in improved NUE and grain yield. We also show that a loss-of-function mutation at the DNR1 locus is associated with increased N uptake and assimilation, resulting in improved rice yield under moderate levels of N fertilizer input. Therefore, modulating the DNR1-mediated auxin response represents a promising strategy for achieving environmentally sustainable improvements in rice yield.

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

“…Numerous studies have supported the idea that N regulation is involved in plant development (Zhang S. et al, 2020;. Based on the previously reported genes and published studies, we conducted candidate gene identification.…”

Effects of NAA and Ecklonia maxima Extracts on Lettuce and Tomato Transplant Production

“…Some specialized carriers mediate the auxin's polar transport: incoming carrier proteins of the family AUX1/LAX and outgoing carrier protein of the PIN family. Researchers have proven that the auxin influx carriers (AUX/LAX family) facilitate the uptake of the natural auxin IAA and the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D), but not the synthetic auxin NAA [45][46][47][48][49][50]. The transport specificities and locations of AUX/LAX family members may contribute to the differences in auxin response.…”

“…According to Dos Santos et al [75], plant responses to nitrogen supply are dependent on auxin signaling, which can be coming from endogenous biosynthesis or exogenous sources. Zhang et al [49] have shown that, on rice (Oryza sativa), the NUE quantitative trait locus is involved in auxin homeostasis. The promotion of auxin biosynthesis results in improved NUE.…”

Plant Endophytic Fungus Extract ZNC Improved Potato Immunity, Yield, and Quality

“…The application of ZNC with controlled-release urea has significantly increased the soil nitrogen supply in the critical period of wheat growth and development ( Qin et al, 2018 ). A recent study demonstrates DULL NITROGEN RESPONSE1 ( DNR1 ) regulates nitrogen metabolism by mediating auxin homeostasis, and OsARFs promotes nitrogen absorption rate by activating the expression of NO 3− metabolic related genes ( Zhang et al, 2021 ). Combined with our research, ZNC promoted the absorption of nitrogen in potatoes, suggesting that ZNC also improves fertilizer utilization efficiency by increasing the absorption of nitrogen in plants ( Figure 2F ), which is beneficial for decreasing fertilizer use and reducing costs in agricultural production.…”