The collaborative team of Chen Yuhang and Zhou Jianmin of the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences cloned the broad-spectrum anti-rhizomatous gene, elucidated its mechanism of action, and borrowed the name of Wei Tsing, a famous general of the Western Han Dynasty in the mainland, and the relevant research was published in Cell at 23:00 Beijing time on June 8, 2023.
Rhizomatosis is the most harmful disease in the agricultural production of cruciferous crops such as rape. This study not only has a good application prospect in the breeding of cruciferous crops resistant to rhizomatous disease, but more importantly, it is the first discovery of calcium ion release channels and their mediated immune mechanisms in plants, which is another major theoretical breakthrough made by mainland scientists in this field after the discovery of plant disease-resistant bodies.
Symptoms of enlarged rape roots affected by rhizomatous disease. Photo courtesy of Yang Hui, associate professor of Sichuan Agricultural University
In view of the major problem of cruciferous crop root swelling disease, the team of Chen Yuhang and Zhou Jianmin used genetics, biochemistry, structural biology and physiology to isolate and identify the gene WTS with high resistance to rhizomatous disease and elucidate its molecular mechanism. WTS encodes a protein that has never been reported, and after being introduced into rape, it not only shows good resistance, but also completely normal growth and development; WTS-carrying rapeseed showed high resistance to multiple rhizomatous bacteria, including highly pathogenic strains on existing resistant varieties, indicating that WTS is a broad-spectrum resistance gene. Therefore, WTS has good application value in the molecular breeding of rapeseed against rhizomatous disease. Further studies found that when rhizomatous is infected, WTS is specifically expressed in the middle column sheath cells and self-assembles as a novel calcium channel localized to the endoplasmic reticulum, which activates the downstream immune response by mediating the release of calcium ions in the endoplasmic reticulum, thereby protecting the root vascular bundle system from pathogens.
Mechanism of action of WTS. WTS encodes calcium channels localized to the endoplasmic reticulum, which triggers downstream immune responses by mediating calcium release, resists the invasion of rhizomates, and protects the plant vascular system.
The results show that plants can not only activate calcium signaling through traditional disease-resistant bodies, but also use other proteins outside the NLR family to assemble new ion channels to activate calcium signaling and immune responses. Unlike the plasmomembrane-localized disease-resistant bodies, the WTS complex is localized to the endoplasmic reticulum, indicating that it is a calcium ion release channel, which is also the first calcium ion release channel found in plants. In addition, the induction and mode of action of WTS in the root-specific cell layer have important reference significance for the study of the resistance mechanism of other soil-borne diseases.
Wang Wei, associate researcher of the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Qin Li, postdoctoral fellow, and doctoral students Zhang Wenjing and Tang Linghui are the first authors of the paper. Researcher Yuhang Chen, Researcher Jianmin Zhou and Associate Professor Wei Wang are the co-corresponding authors of the paper. Also participating in the work were Huang Yun's team from Sichuan Agricultural University and Liang Chengzhi's team from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences.
Field-grown canola. Photo courtesy of Hu Baocheng, researcher of Anhui Academy of Agricultural Sciences