Kynurenine pathway as alternative biosynthetic pathway for fusaric acid in Fusarium oxysporum f.sp. cubense

Banana fusarium wilt caused by Fusarium. oxysporum f.sp. cubense race 4, has already become one of the main diseases in banana production. Previous research suggests that Foc can secrete two phytotoxins, respectively, fusaric acid and beauvericin, to contribute to its pathogenicity when it infects bananas. A gene cluster FUB consisting of 12 genes has been identified for fusaric acid biosynthesis in several Fusarium spp, including Fusarium. oxysporum f.sp. cubense race 4, F. oxysporum f.sp. lycopersici etc. In the present study, using reverse genetic research methods, we report the evidence for the kynurenine pathway as alternative biosynthetic pathways of fusaric acid in F. oxysporum f.sp. cubense 4. In the meanwhile, our experiments suggests that the beauvericin might not directly contribute to the pathogenicity to banana of F. oxysporum f.sp. cubense 4.