Cloning And Functional Analysis Of CMK,PLA2 And PLC Genes In Magnaporthe Oryzae Involving In Ca²⁺ Signaling Pathway

Magnaporthe oryzae(M.oryzae)is an important ascomycete that causes rice blast.Studying of the disease-caused basis of M.oryzae is not only beneficial for rice blast control,but also served as a model for revealing other fungal pathogen-plant interactions.The process of conidial germination,appressorial differentiation and infection to plant in M.oryzae is precisely and complicatedly controlled by a serial of genes.The formation of the appressorium of M.oryzae is a complicated process,including the apperception of the leaf blade surface induction,the transmembrane conduction of the signal and the originated phosphorylationcascade reaction in cell.As one of the four signaling pathways that accommodate the formation of M.oryzae's appressorium, Ca²⁺signaling pathway participates in controlling the conldial germination and appressorium formation under the condition of scanty of water.In this study,we isolated three Ca²⁺signaling pathway-related genes,CMK, PLA2 and PLC,from the rice blast fungus,and deleted it in the fungus strain Guy11. CMK gene encodes a CaM dependent protein kinase;PLA2 gene encodes a Ca²⁺-activated phospholipase A2;and PLC gene encodes a phosphoinositide-specific phospholipase C.â–³CMK null mutants showed a phenotypes defective in growth and development, such as sparse hyphae when grew on CM medium plates,decreased conidiation, delayed conidial germination and appressorial formation,and highly mild pathogenicity to rice and barley.The mating ability ofâ–³CMK mutants crossing with strain 2539 was also deadly impaired.â–³PLA2 null mutants also showed defects in colonial morphology,conidiation, conidial germination and appressorial formation;the pathogenicity of these null mutants on rice and barley was weakened too.However,different fromâ–³CMK,the mating ability ofâ–³PLA2 mutants crossing with strain 2539 was not impaired.These results revealed byâ–³CMK andâ–³PLA2 mutants suggested that Ca²⁺ signaling pathway is required for the conidial germination,appressorial formation and pathogenicity of M.oryzae.