VQ motif-containing proteins as signaling integrators in halophytes: regulatory role of LbVQ6 in salt gland development and salinity adaptation
Abstract
VQ motif-containing proteins represent a plant-specific class of transcriptional cofactors that integrate developmental and stress-responsive signaling pathways. Recent genome-wide characterization of the VQ gene family in the recretohalophyte L. bicolor identified LbVQ6 as a key regulator of salt gland development and salinity tolerance. Here, we synthesize previously published evidence on the signaling role of LbVQ6 and position it within regulatory networks involving MAPK-mediated phosphorylation cascades, WRKY transcription factor interactions, phytohormone signaling, and redox homeostasis. Functional silencing of LbVQ6 as reported in earlier studies results in a marked reduction in salt gland density, disruption of ionic balance, and increased accumulation of reactive oxygen species, demonstrating its essential role in both structural and physiological adaptation to saline environments. Promoter cis-element analysis further suggests that LbVQ6 integrates ABA-, JA-, and SA-dependent stress signaling pathways, although functional validation of these regulatory interactions remains necessary. Collectively, these findings highlight VQ-mediated regulatory networks as critical components of halophyte stress adaptation. The identification of LbVQ6-centered signaling pathways provides promising molecular targets for engineering salinity tolerance in crop species. Future studies focusing on protein interaction networks, post-translational regulation, and downstream transcriptional programs will further clarify the role of VQ proteins in plant stress signaling.