Jingyi Wang, Long Li, Chaonan Li, Matthew Reynolds, Manuel Spannagl, Jörg-Peter Schnitzler, Yang Zhao, Zilong Ma, Jiemeng Xu, Xinguo Mao, Ruilian Jing

Journal of Advanced Research; 2026; IF: 13.0

DOI: 10.1016/j.jare.2026.03.018

Abstract

Introduction: Numerous studies have elucidated plants'drought response, yet how plant leaves perceive this stress remains unclear.

Objectives: This study aims to deepen the understanding of how leaves perceive and respond to water loss.

Methods: Detached-leaf water loss rate was detected, which can effectively eliminate the effects of water absorption and water transport. Subsequently, a genome-wide association study (GWAS) was carried out on the detached-leaf water loss rate.

Results: There was a significant association between the TaWAK5 (cell wall-associated kinase) gene and the detached-leaf water loss rate. The results from the phenotypic analyses of the overexpression lines and CRISPR/Cas9 mutant lines revealed the function of TaWAK5 in the wheat’s response to drought stress. Subsequent study exhibited that drought induced the degradation of pectin into oligo-galacturonides (OGs), and OGs have higher affinity with TaWAK5 than pectin. OGs can activate TaWAK5 kinase, leading to stomatal closure. Additionally, TaWAK5 phosphorylates TaSLAC1 (slow anion channel-associated 1), a key component regulating stomatal movement. A single nucleotide polymorphism site SNP-947 (G/A) at 947 bp of the cis-element in the TaWAK5 promoter region is significantly associated with TaWAK5 expression, detached-leaf water loss rate and canopy temperature, and leads to the bZIP transcription factor TaPAN (PERIANTHIA) functioning as a transcriptional activator in haplotype Hap3/4, but not in Hap1/2 of TaWAK5.

Conclusion: This study suggests that TaWAK5 perceives OGs to activate drought responses in wheat, highlighting a potential target for enhancing the drought tolerance of wheat.