SPL transcription factors in plants: a potential stress regulator

Squamosa promoter binding-like proteins (SPLs) are ubiquitous transcription factors (TFs) in higher plants and play key roles in plant response to biotic and abiotic stresses. There is abundant experimental evidence that SPL TFs can specifically bind to cis-elements in the promoter region of stress-related genes to repress or activate the expression of downstream genes, thus mediating plant adaptive responses. Here, the review outlines recent data on the interaction mechanisms between SPLs and microRNA, phytohormonal signaling (indole-3-acetic acid, salicylic acid, methyl jasmonate, jasmonic acid, abscisic acid, and gibberellin), other TFs (bHLH, WRKY, NAC, ZAT, and CBF) and epigenetic regulation under stress conditions. This review systematically describes the action mechanisms of SPL TFs and epigenetic regulation in plants under stress condition and prospects the directions and challenges of future work, which provides useful insights for further investigation of the molecular mechanisms and functions of SPL TFs in plants under adverse environment.