A Secretory Protein Laccase lac8 From Pathogenic Fungi Activates Plant Protein 14-3-3 and Leucine-Rich Repeat...

Plants cope with the biotic stress caused by pathogen infection through complex resistance mechanisms. Here, we identified a secreted laccase Cglac8 from Colletotrichum gloeosporioides and confirmed its involvement in C. gloeosporioides infection of mango (Mangifera indica) plants, as well as its ability to activate the host's innate immune mechanism. Cglac8 interacted with MiLRR-RLP1 and Mi14-3-3-D1 as demonstrated by yeast two-hybrid, bimolecular fluorescence complementation and pull-down assays. The interacting proteins MiLRR-RLP1 and Mi14-3-3-D1 positively regulate mango resistance to C. gloeosporioides by promoting the reactive oxygen species burst and biosynthesis of phytohormones. When Cglac8, MiLRR-RLP1 and Mi14-3-3-D1 proteins were overexpressed together in mango, the resistance of mango to C. gloeosporioides was significantly enhanced. Our findings reveal a new defence mechanism of host plants against C. gloeosporioides, providing a theoretical basis for disease-resistant molecular breeding. The dual role of secretory laccase Cglac8 may reflect a balancing mechanism in host-pathogen co-evolution.