Identification of a pigment-polyketide synthase gene deleted mutant of Monascus ruber M7

Abstract:

Abstract:［Objective］ To reveal the function of a polyketide synthase gene (pksPT)，probably responsible for the synthesis of Monascus pigments in Monascus ruber M7.［Methods］The pksPT was analyzed using bioinformatics method; it was disrupted using Agrobacterium tumefaciens mediated transformation method，generating the pksPT-deleted mutant (ΔpksPT)．Colonial morphology，conidial germination，pigment and citrinin production，and growth rate of ΔpksPT were analyzed.［Results］The pksPT with the length of 8687 bp encoded a putative protein of 2690 amino acids，which is a non-reduced type III polyketide synthase and has some active domains with the arrangement of KS (β-ketosynthase)-AT (Acyltransferase)-ACP (Acyl carrier protein)-ACP-ME (Methyltransferase)．The analysis of ΔpksPT displayed that it could generate cleistothecum and conidum normally and was unable to produce any kinds of Monascus pigments; compared to M7，the growth rate of ΔpksPT was increased obviously and the yield of citrinin in ΔpksPT was increased about 2.8 times.［Conclusion］pksPT is of extremely importance to the biosynthetic pathways of Monascus pigments in M7 and the synthesis of Monascus pigments gives a significant effect on the produce of citrinin as well as the growth of M7.