Identification of key enzyme genes of kynurenine pathway in Botrytis cinerea

Abstract:

[Background] Botrytis cinerea is an important phytopathogenic fungus. In previous studies, it was confirmed that the BcKMO gene encoding kynurenine 3-monooxygenase (KMO) is involved in the regulation of the growth and pathogenicity of Botrytis cinerea. KMO is a key enzyme in the kynurenine pathway, but the presence of the kynurenine pathway in Botrytis cinerea and its function in the growth, development and pathogenesis of pathogens have not yet been related reported. [Objective] To identify the key enzyme genes in the kynurenine pathway of Botrytis cinerea, and to determine the presence of kynurenine pathway in Botrytis cinerea, lay the foundation for elucidating the molecular mechanism of growth and pathogenicity of Botrytis cinerea. [Methods] Bioinformatics methods were used to analyze the coding genes of key enzyme, kynureninase (KYN), indoleamine-2,3-dioxygenase (IDO), and kynurenine amino transferase (KAT), in the kynurenine pathway of Botrytis cinerea. Real-time PCR was used to detect the expression level of key enzyme genes of the kynurenine pathway in Botrytis cinerea wild-type BC22, BcKMO mutant BCG183, and the BcKMO complementing strain BCG183/BcKMO. The content of kynureninase in the BcKMO mutant was determined by using a fungal kynureninase assay kit. [Results] Botrytis cinerea contains 2 genes coding KYN, 3 genes coding IDO, and 10 genes coding KAT. The expression levels of Botrytis cinerea KYN, IDO, KAT coding genes in mutant BCG183 were significantly higher or lower than those in BC22 and BCG183/BcKMO. The content of kynureninase (KYN) in the mutant BCG183 was significantly lower than that of BC22 and BCG183/BcKMO. [Conclusion] Kynurenine pathway is present in Botrytis cinerea. BcKMO mutation affects the expression of KYN, IDO and KAT encoding genes and the content of kynureninase (KYN) in Botrytis cinerea.