JAZ2 negatively regulates drought tolerance in barley by modulating PLT2
expression
Abstract
Drought is an important abiotic factor constricting crop production
globally. Although the role of JAZ proteins in regulating jasmonic acid
signaling and plant responses to environmental stress is well
documented, their specific functions and underlying mechanisms in plants
remains 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 as 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 up-regulated 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 is not directly interacted 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
activates the HvPLT2 promoter. In summary, HvJAZ2 negatively regulates
root development and drought tolerance in barley by suppressing HvPLT2
expression through interacting with HvMYC2.