Plant receptor-like kinases (RLKs) regulate many processes in plants. Many RLKs perform significant roles in plant immunity. Lectin receptor-like kinases (LecRLKs) are a large family of RLKs. However, the function of most LecRLKs is poorly understood. In this study, we show that a potato LecRLK, StLecRK-IV.1, is involved in plant immunity against Phytophthora infestans. As a negative regulator of immunity, StLecRK-IV.1 is downregulated by P. infestans and activated by abscisic acid. The transient expression of StLecRK-IV.1 in Nicotiana benthamiana enhanced P. infestans leaf colonization significantly. In contrast, the size of disease lesions caused by P. infestans was reduced by virus-induced gene silencing of the StLecRK-IV.1 ortholog in N. benthamiana, NbLecRK-IV.1, as well as in potato plants with stable RNA interference of StLecRK-IV.1. Tetraspanin-8 (StTET8) was identified to be interacting with StLecRK-IV.1 using a membrane yeast two-hybrid system, which was further verified by co-immunoprecipitation, a luciferase complementation assay, and a bimolecular fluorescence complementation test. StTET8 is a positive immune regulator that restrains P. infestans infection. The co-expression of StLecRK-IV.1 with StTET8 antagonized the positive roles of StTET8 against P. infestans. Moreover, the co-expression of StTET8 with StLecRK-IV.1 affected the stability of StTET8, which was confirmed by a western blot assay and confocal assay. Taken together, our work first reveal that a potato L-type lectin RLK, StLecRK-IV.1, negatively regulates plant immunity by targeting a positive regulator, StTET8, through affecting its stability.

Drought stress poses a significant threat to rice production, necessitating the identification of genes associated with drought tolerance. This study employed a combination of genome-wide association study (GWAS) and linkage mapping to pinpoint seedling drought tolerance genes in Japonica rice. Using the leaf rolling scale (LRS) as the phenotypic index, we assessed rice drought tolerance under polyethylene glycol-induced drought during the seedling stage. A lead SNP C8_28933410 by GWAS was identified, which was located within qLRS-8-1 identified by linkage mapping on chromosome 8. Combing the LD block analyses and QTL interval, a 138.6 kb overlap interval was considered as the candidate region. Haplotype analysis, qRT-PCR, sequence analysis, and mutant phenotype verification led to the speculation that LOC_Os08g05520 is a candidate gene associated with drought tolerance. Our findings provide a valuable reference for breeders aiming to enhance rice drought tolerance.