Inactivation of MrPigH in Monascus ruber M7 Results in its Monascus Pigments Increase and Citrinin Decrease with mrpyrG Selection Marker

Monascus pigments (MPs) have been used as food colorants for several centuries in Asian countries and nowadays in the whole world via Asian catering. The MPs biosynthetic pathway has been well-illustrated, however, the functions of a few genes including mrpigH in the MPs gene cluster of M. ruber M7 are still unclear. In current study, mrpigH was disrupted in Δmrlig4ΔmrpyrG, a highly efficient gene modification system, using mrpyrG as a selection marker, and ΔmrpigHΔmrlig4ΔmrpyrG::mrpyrG and ΔmrpigHΔmrlig4ΔmrpyrG have been obtained. Subsequently, their morphologies, biomasses, MPs and citrinin (CIT) production were analyzed, respectively. These results have revealed that the deletion of mrpigH has significant effects on the morphology and growth of M. ruber M7. Moreover, compared with M. ruber M7, the yields of MPs and CIT were drastically increased and decreased in mrpigH mutants, respectively.