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

Abstract

Aromatic rice is globally favored for its distinctive scent, which not only increases its nutritional value but also enhances its economic importance. However, apart from 2-acetyl-1-pyrroline (2-AP), the metabolic basis of aroma remains to be clarified, and the genetic basis of the accumulation of fragrance metabolites is largely unknown. In this study, we revealed 2-AP and fatty acid-derived volatiles (FAVs) as key contributors to rice aroma by combining aroma rating with molecular docking. Using a volatilome-based genome-wide association study, we identified two regulatory genes that determine the natural variation of these fragrance metabolites. Genetic and molecular analyses showed that OsWRKY19 not only enhances fragrance by negatively regulating OsBADH2 but also improves agricultural traits in rice. Furthermore, we revealed that OsNAC021 negatively regulates FAV contents via the lipoxygenase pathway, and its knockout resulted in over-accumulation of grain FAVs without a yield penalty. Collectively, our study not only identifies two key regulators of rice aroma but also provides a compelling example about how to deciphering the genetic regulatory mechanisms that underlie rice fragrance, thereby paving the way for the creation of aromatic rice varieties.