Effects of VeA Gene on the Growth, Pigment and Citrinin Synthesis of Monascus ruber M7

<i>Monascus</i> spp. is widely used in food fermentation and additive production, and some of its strains produce citrinin (CIT), which is nephrotoxic. In this study, we constructed a mutant strain of <i>Monascus ruber</i> M7 (<i>M. ruber</i> M7) with a <i>VeA</i> gene deletion (<i>ΔVeA</i>) using the <i>Agrobacterium</i>-mediated transformation technique to investigate the <i>VeA</i> gene in growth and development, pigmentation, and CIT synthesis in <i>M. ruber</i> M7. Compared to the wild-type strain (WT), the <i>ΔVeA</i> strain grew faster, the mycelium was dense, the length was longer, the colony color was lighter, the cleistothecium and conidia were reduced, the ability to produce <i>Monascus</i> pigments (MPs) decreased, and CIT was not produced. Transcriptomic results showed that differentially expressed genes (DEGs) were mainly enriched in amino sugar metabolism, the MAPK signaling pathway and carbohydrate metabolism. These results suggest that the <i>VeA</i> gene negatively regulates the growth and development of <i>M. ruber</i> M7 and positively regulates its sexual/asexual reproduction, MPs, and CIT production. The results of this study can provide a reference for industrial applications of <i>Monascus</i> with low or even no CIT production.