Functional Analysis Of Chorismate Mutase In Magnaporthe Oryzae

The shikimate pathway is a primary metabolic route in plants and microorganisms, its end product is chorismic acid. To be the precursor, chorismic acid can be converted into the three aromatic amino acids and a vast array of secondary metabolites, such as SA involved in plant defense, auxin IAA, and other chorismate-derived compounds （CDCs）.Chorismate mutase is a member of the shikimate pathway, catalyzes the conversion of chorismate to prephenate through pericyclic claisen rearrangement, providing the precursors for the synthesis of phenylalanine and tyrosine. Because chorismate mutase is an unusual and essential enzyme, it has been widely studied in many organisms, for example, Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae, Ustilago maydis, Arabidopsis thaliana, Meloidogyne javanica and so on. It is surprisingly found that chorismate mutase play another important role in altering plant cell development in obligate parasitism, biotrophic and hemibiotrophic organisms besides the essential enzyme in the primary metabolic pathway. We here studied the function of chorismate matase in Magnaporthe oryzae.There is only one chorismate mutase （MGG₀1710） annotated in the genomic database of Magnaporthe oryzae, we defined it as MoCM （chorismate mutase in Magnaporthe oryzae）. Then we obtained knockout mutants through the approach of homologous recombination. Further, we analyzed the basic phenotype of these mutants. It shows that the aerial hyphae of mutants reduced obviously, compared to their parent strain △Ku80. The defect phenotypes of mutants such as the decrease of conidiation, the delay of germinmation and appressorium, as well as the decrease of penetration rate and infection with onion have been observed in knockout mutants of MoCM. These results suggest that chorismate mutase not only affect the vegetative growth, but also play a role in pathogenicity.