High-temperature adaptation of an <i>OsNRT2.3</i> allele is thermoregulated by small RNAs.

Abstract

Climate change negatively affects crop yield, which hinders efforts to reach agricultural sustainability and food security. Here, we show that a previously unidentified allele of the nitrate transporter gene <i>OsNRT2.3</i> is required to maintain high yield and high nitrogen use efficiency under high temperatures. We demonstrate that this tolerance to high temperatures in rice accessions harboring the HTNE-2 (high temperature resistant and nitrogen efficient-2) alleles from enhanced translation of the <i>OsNRT2.3b</i> mRNA isoform and the decreased abundance of a unique small RNA (sNRT2.3-1) derived from the 5' untranslated region of <i>OsNRT2.3</i>. sNRT2.3-1 binds to the <i>OsNRT2.3a</i> mRNA in a temperature-dependent manner. Our findings reveal that allelic variation in the 5' untranslated region of <i>OsNRT2.3</i> leads to an increase in OsNRT2.3b protein levels and higher yield during high-temperature stress. Our results also provide a breeding strategy to produce rice varieties with higher grain yield and lower N fertilizer input suitable for a sustainable agriculture that is resilient against climate change.