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Article|25 Apr 2023|OPEN
Tomato LysM receptor kinase 4 mediates chitin-elicited fungal resistance in both leaves and fruit
Yingfei Ai1 , Qinghong Li1 , Chenying Li1 , Ran Wang1 , Xun Sun1 , Songyu Chen1 , Xin-Zhong Cai2 , Xingjiang Qi3 , and Yan Liang,1 ,
1State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Department of Plant Protection, Zhejiang University, Hangzhou, 310058, China
2Hainan Institute, Zhejiang University, Sanya, 572025, China
3Zhejiang Xianghu Laboratory, Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
*Corresponding author. E-mail:,

Horticulture Research 10,
Article number: uhad082 (2023)
Views: 147

Received: 30 Oct 2022
Accepted: 18 Apr 2023
Published online: 25 Apr 2023


Fungal infection is a major cause of crop and fruit losses. Recognition of chitin, a component of fungal cell walls, endows plants with enhanced fungal resistance. Here, we found that mutation of tomato LysM receptor kinase 4 (SlLYK4) and chitin elicitor receptor kinase 1 (SlCERK1) impaired chitin-induced immune responses in tomato leaves. Compared with the wild type, sllyk4 and slcerk1 mutant leaves were more susceptible to Botrytis cinerea (gray mold). SlLYK4 extracellular domain showed strong binding affinity to chitin, and the binding of SlLYK4 induced SlLYK4-SlCERK1 association. Remarkably, qRT–PCR analysis indicated that SlLYK4 was highly expressed in tomato fruit, and β-GLUCURONIDASE (GUS) expression driven by the SlLYK4 promoter was observed in tomato fruit. Furthermore, SlLYK4 overexpression enhanced disease resistance not only in leaves but also in fruit. Our study suggests that chitin-mediated immunity plays a role in fruit, providing a possible way to reduce fungal infection-related fruit losses by enhancing the chitin-induced immune responses.