Epistatic Relationship between and in the Regulation of Biosynthetic Gene Clusters in .

Genetic studies have shown that the MAP kinase MGV1 and the transcriptional regulator TRI6 regulate many of the same biosynthetic gene clusters (BGCs) in . This study sought to investigate the relationship between and in the regulatory hierarchy. Transgenic strains constitutively expressing and were generated to address both independent and epistatic regulation of BGCs by and . We performed a comparative transcriptome analysis between axenic cultures grown in nutrient-rich and secondary metabolite-inducing conditions. The results indicated that BGCs regulated independently by included genes of BGC52, whereas genes uniquely regulated by included the gene cluster (BGC49) that produces gramillin. To understand the epistatic relationship between and , CRISPR/Cas9 was used to insert a constitutive promoter to drive expression in the Δ strain. The results indicate that BGCs that produce deoxynivalenol and fusaoctaxin are co-regulated, with being partially regulated by . Overall, the findings from this study indicate that MGV1 provides an articulation point to differentially regulate various BGCs. Moreover, TRI6, embedded in one of the BGCs provides specificity to regulate the expression of the genes in the BGC.