Clathrin light chains negatively regulate plant immunity by hijacking the autophagy pathway

The crosstalk between clathrin-mediated endocytosis (CME) and the autophagy pathway has been reported in mammals; however, the interconnection of CME with autophagy has not been established in plants. Here, we report that the Arabidopsis CLATHRIN LIGHT CHAIN (CLC) subunit 2 and 3 double mutant, clc2-1 clc3-1, phenocopies Arabidopsis AUTOPHAGY-RELATED GENE (ATG) mutants in both autoimmunity and nutrient sensitivity. Accordingly, the autophagy pathway is significantly compromised in the clc2-1 clc3-1 mutant. Interestingly, multiple assays demonstrate that CLC2 directly interacts with ATG8h/ATG8i in a domain-specific manner. As expected, both GFP-ATG8h/GFP-ATG8i and CLC2-GFP are subjected to autophagic degradation, and degradation of GFP-ATG8h is significantly reduced in the clc2-1 clc3-1 mutant. Notably, simultaneous knockout of ATG8h and ATG8i by CRISPR-Cas9 results in enhanced resistance against Golovinomyces cichoracearum, supporting the functional relevance of the CLC2–ATG8h/8i interactions. In conclusion, our results reveal a link between the function of CLCs and the autophagy pathway in Arabidopsis.