Fungal hyphae self-assemble a variety of cellular macrostates, ranging from suspended mycelium to dense pellets, all inextricably linked to their productivity. In this study, using CRISPR/Cas technology, we constructed a ctnA knockout strain (ΔctnA) and an overexpression strain (A2) so as to investigate the effects of interfering with citrinin biosynthesis on the growth, morphology and pigmentation of M.purpureus. Results indicated that deletion of ctnA in M. purpureus RP2 led to increased mycelium length, delayed conidium formation, and a citrinin content of 22% of the wild-type strain. Conversely, ctnA overexpression in strain A2 resulted in delayed mycelial growth, normal conidium formation, and a citrinin content of 120% compared to the wild-type strain, with minimal effects on pigments content. Notably, the ΔctnA strain formed small, tightly structured pellets (mean diameter 1.2 ± 0.06 mm) and exhibited low citrinin content, promoting pigments production. Our findings suggest a complex interplay between citrinin biosynthesis and morphological development, providing insights for optimizing metabolite production in industrial applications.
Keywords: CRISPR/Cas9; Citrinin biosynthesis; Fungal morphology; Monascus purpureus; Secondary metabolism.
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