Discovery of specific rhizosphere bacteria Rhodanobacter involved in KAI2-mediated drought tolerance in Arabidopsis
- Yu Sun
- Hengfei Zhang
- Gang Ye
- Shuhua Liu
- Zongmu Yao
- Lei Tian
- Jingjing Chang
- Yuxuan Hu
- Wenbo Jia
- Zhongjun Jia
- Mostafa Abdelrahman
- Yuchun Yan
- Tianzuo Wang
- Xianzhong Feng
- Lam-Son Phan Tran
- Chunjie Tian
- Weiqiang Li
- Xiaojian Yin
2026-07-01
The KARRIKIN INSENSITIVE 2 (KAI2) receptor has been reported to contribute to drought tolerance in Arabidopsis . However, the extent to which KAI2’s function in drought tolerance depends on soil microbiota remains unclear. This study demonstrates that the rhizosphere microbiome is indispensable for KAI2-mediated drought tolerance. We isolated specific Rhodanobacter sp. and confirmed its role in enhancing drought tolerance in Arabidopsis . Notably, Rhodanobacter sp. was found to specifically secrete the key isoflavone daidzin. We found that daidzin had a similar function with KAI2 agonist, desmethyl-type germinone, and induced interaction between KAI2 and SUPRESSOR OF MORE AXILLARY GROWTH 2 1. Moreover, the exogenous application of daidzin enhanced drought tolerance by modulating the expression of karrikin response and drought-related genes, in a KAI2-dependent manner. Our findings suggest that the rhizosphere microbiome plays a crucial role in facilitating KAI2-mediated drought tolerance in Arabidopsis , with Rhodanobacter sp. contributing through the secretion of daidzin.