The genetic alchemy: deciphering WRKY's role in the flavor quality of horticultural crops

Abstract

Fruits of horticultural crops are indispensable sources of nutrients and bioactive compounds, and their flavor quality, a complex phenotypic trait orchestrated by soluble sugars, organic acids, volatile aromas, is a pivotal determinant of their market competitiveness and consumer preference. Enhancing flavor quality has therefore become a primary priority of horticultural crop breeding. WRKY transcription factors (TFs) constitute one of the largest TF families in plants, and are emerging as central regulators of specialized metabolism underlying fruit flavor formation. In this review, we first identify two core evolutionary features of WRKY TFs in horticultural crops: cross-species conserved sucrose-acid regulatory clades and species-specific flavor regulatory clades. We then systematically summarize the regulatory roles of WRKY TFs in the accumulation of sugars, organic acids, volatile aromas, and bitter/pungent substances, and elaborate on the molecular mechanism by which they integrate environmental and hormone signals to coordinate flavor metabolism. We further propose a multi-dimensional regulatory model of WRKY-mediated flavor formation, and discuss future research directions as well as potential applications in molecular breeding for flavor enhancement. This work provides a comprehensive framework for understanding the role of WRKY in flavor regulation and offers guidance for the cultivation of high-quality horticultural crops.