High-temperature adaptation of an allele is thermoregulated by small RNAs.

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 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 mRNA isoform and the decreased abundance of a unique small RNA (sNRT2.3-1) derived from the 5' untranslated region of . sNRT2.3-1 binds to the mRNA in a temperature-dependent manner. Our findings reveal that allelic variation in the 5' untranslated region of 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.