Functional Identification Of Regulator LaeB And Pigment Synthetic Gene Pks1 In Aspergillus Flavus

Aspergillus flavus is a common saprophytic soil fungus,which mainly causes infections in oil crops and food,and leads the enormous losses of the national agricultural economic development and world food storage.A.flavus is the main producer of aflatoxin,a strong carcinogenic mycotoxin.Aflatoxin can cause poisoning and even liver cancer to human and animals.Global regulator,and the conidial pigments play an important role in the fungal development and secondary metabolism.According to global regulator and conidial pigment,the study explored their effects on the growth and secondary metabolism of A.flavus.In this study,we investigated the biological function of LaeB in A.flavus by consulting laeB knockout mutant strain??laeB?.Compared?laeB with wild-type strain,the?laeB had a slower grow rate and increased production of conidia.The production of sclerotia is restrained in?laeB.LaeB also regulated secondary metabolite production,especially for production of AFB₁.And?laeB showed a reduced infection in maize and peanut seeds.In this study,we identified the synthetic genes and gene cluster of conidial pigment in A.flavus by genomic data mining and sequence alignment.The?pks1 lost the conidial color instead of producing the white conidia,which is the skeleton gene of conidial pigment synthesis,and resulted in decreasing resistance to UV radiation and the ability to infect corn and peanut seeds.No obvious difference was showed in the growth rate,spore yield,formation of stress-resistant structure sclerotia and production of AFB₁ between WT and?pks1 strains.There were also no differences in cell wall integrity,water activity changes and oxidative stress.In conclusion,global regulator LaeB can regulatethe fungal development,secondary metabolism and pathogenicity in A.flavus,and the conidial pigment synthesis gene pks1 affects the resistant to UV radiation and infection of crops.This study not only provides a theoretical basis for further research on fungal development,secondary metabolism and pathogenicity in A.flavus,but also is beneficial to aflatoxin pollution prevention and the development of new pesticides.