A β‐1,3‐glucanase antagonizes a phase‐separating
WRKY
repressor to confer saline–alkaline tolerance in rice
Tian‐Jing Wang, Shuangzhan Huang, Xin Tian, Dongxiao Zhou, Jianying Xing, Wenxin Liu, Wenhui Xu, Shangyong Xue, Shitao Li, Dae‐Jin Yun, Xinglin Du, Zheng‐Yi Xu Summary
Saline–alkaline stress imposes combined ionic and high‐pH challenges that severely limit rice productivity, yet the molecular mechanisms linking stress perception to transcriptional reprogramming remain poorly understood.
Here, we identify the WRKY transcription factor OsWRKY1 as a central negative regulator of saline–alkaline tolerance in rice. Loss of
OsWRKY1
markedly enhances stress tolerance, whereas its overexpression causes hypersensitivity. Using inducible transcriptomics and DAP‐seq, we show that OsWRKY1 directly represses genes involved in ion transport, nutrient uptake, osmotic adjustment, and redox homeostasis.
Unexpectedly, OsWRKY1 undergoes stress‐induced liquid–liquid phase separation (LLPS) in the nucleus, driven by a long intrinsically disordered region (IDR1) that is required for its full repressive activity. Saline–alkaline stress specifically induces the binding of the β‐1,3‐glucanase OsGH17 to OsWRKY1. OsGH17 directly interacts with IDR1, reduces OsWRKY1 DNA binding, decreases OsWRKY1 condensate formation, and relieves OsWRKY1‐mediated transcriptional repression. Genetic epistasis indicates that
OsWRKY1
and
OsGH17
function in the same pathway in the saline–alkaline stress response, with
OsWRKY1
being epistatic to
OsGH17
.
Together, our findings reveal a previously unrecognized mechanism in which a β‐1,3‐glucanase with a noncanonical regulatory role modulates the behavior of a phase‐separating transcriptional repressor and promotes stress‐responsive gene expression, providing new insight into plant adaptation to saline–alkaline environments.