JAZ2 Negatively Regulates Drought Tolerance in Barley by Modulating PLT2 Expression

• Published in: Plant, cell and environment cell and environment, 2025-01, Vol.48 (1), p.699-710
• Main Authors: Xiong, Jiangyan, Huang, Binbin, Peng, Di, Shen, Qiufang, Wu, DeZhi, Zhang, Guoping
• Format: Article
• Language: English
• Subjects: Barley; Crop production; drought; Drought Resistance; drought stress; drought tolerance; Droughts; environmental factors; Environmental stress; Gene Expression Regulation, Plant; genes; Hordeum - genetics; Hordeum - metabolism; Hordeum - physiology; interaction; Jasmonate Zim‐domain protein (JAZ); Jasmonic acid; Mutants; Nuclear interactions; Phylogeny; Plant growth; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Roots - genetics; Plant Roots - growth & development; Plant Roots - metabolism; Plant Roots - physiology; Proteins; regulation; Root development; root growth; Stress, Physiological - genetics; Subgroups
• ISSN: 0140-7791; 1365-3040; 1365-3040
• DOI: 10.1111/pce.15149

ABSTRACT Drought is an important abiotic factor constricting crop production globally. Although the roles of JAZ proteins in regulating jasmonic acid signalling and plant responses to environmental stress are well documented, their specific functions and underlying mechanisms remain little known. In this study, JAZ proteins in barley were thoroughly analyzed, revealing a total of 11 members classified into three phylogenetic subgroups. HvJAZ2, based on its distinct expression patterns, is considered a key candidate gene for regulating drought tolerance in barley. Using the HvJAZ2 knockout mutants, we revealed that the gene negatively regulates drought tolerance by inhibiting barley root growth. Notably, the jaz2 mutants upregulated the expression of root development genes, including SHR1, PLT1, PLT2 and PLT6. plt2 and plt1/plt2 mutants exhibited suppressed root development and reduced drought tolerance. Analysis of interactions between HvJAZ2 and other proteins showed that HvJAZ2 does not directly interact with HvPLT1/2/6, but interacts with some other proteins. BIFC and LCA assays further confirmed the nuclear interaction between HvJAZ2 and HvMYC2. Y1H and Dual‐Luciferase experiments demonstrated that HvMYC2 can bind to and activate the HvPLT2 promoter. In summary, HvJAZ2 negatively regulates root development and drought tolerance in barley by suppressing HvPLT2 expression through interacting with HvMYC2. Summary statement Drought is a major abiotic factor limiting crop production globally. This study found HvJAZ2 negatively regulates drought tolerance in barley (Hordeum vulgare L.) by suppressing HvPLT2 expression through interacting with HvMYC2, which is potentially useful for improving barley's drought tolerance.