Volatilome-based GWAS identifies OsWRKY19 and OsNAC021 as key regulators of rice aroma.

Abstract

Aromatic rice is globally favored for its distinctive scent, not only increasing nutritional value but also enhancing economic importance. However, apart from 2-acetyl-1-pyrroline (2-AP), the metabolic basis of aroma remains elusive, and the genetic underlying of the accumulation of fragrance metabolites are largely unknown. Here, we revealed 2-AP and fatty acid-derived volatile metabolites (FAVs) as key contributors to rice aroma by combining aroma rating with molecular docking. Using volatilome-based GWAS, we identified two regulatory genes that determine the natural variation of these fragrance metabolites. We demonstrated that OsWRKY19 not only enhances fragrance by negatively regulating OsBADH2 but also promotes agricultural traits in rice. Additionally, we revealed OsNAC021 that negatively regulates FAVs through the LOX pathway, and the knockout of it resulted in the over-accumulation of grain FAVs without a yield penalty. Our findings provide a compelling example of deciphering the genetic regulatory mechanisms underlying rice fragrance and pave the way for the creation of aromatic rice varieties.