Bifunctional transcription factors: recent advances in growth and development, stress resistance, and quality formation of fruits and vegetables.

Fruits and vegetables are key components of the human diet, valued for their unique textures and flavors. In recent years, numerous studies have demonstrated that individual transcription factors (TFs) can simultaneously regulate two biological processes; these TFs are defined as bifunctional TFs. However, systematic reviews on these bifunctional TFs in fruits and vegetables remain limited. This review systematically summarizes current knowledge on bifunctional TFs in fruits and vegetables, focusing on three themes: (i) molecular mechanisms (cis-element diversity, partner switching, posttranslational); (ii) network topology (hubs vs bottlenecks); and (iii) agronomic trade-offs. Meanwhile, the functional conservation and divergence of homologous TFs in different fruits and vegetables have also been investigated. In addition, we elaborate how key TF families, including MYB, bHLH, WRKY, ERF, and NAC, regulate diverse physiological processes in fruits and vegetables via dual mechanisms. We also identify several limitations in the existing literature, such as insufficient understanding of bifunctional regulatory mechanisms, incomplete identification of target genes, and inadequate exploration of crop applications.