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Fu G, Xu Y, Li Y, Tan W.
Construction
of a replacement vector to disrupt pksCT gene for the mycotoxin
citrinin biosynthesis in Monascus aurantiacus and maintain food
red pigment production.
Asia Pac J Clin Nutr. 2007;16 Suppl 1:137-42.
Key Laboratory of Food Science of
Ministry of Education, Jiangxi-OAI Joint Research Institute,
Nanchang University, 235 East Nanjing Road, Nanchang, Jiangxi,
China 330047.
More and more people pay attention to
citrinin produced by Monascus, which has nephrotoxic activity in
mammals. It was reported that pksCT gene is responsible for
citrinin biosynthesis in Monascus purpureus. In this paper, two
DNA fragments in both ends of pksCT were amplified by genomic
PCR from fourteen Monascus spp. strains. The PCR products were
gained from all of the strains. It is suggested that pksCT gene
was highly conserved in different citrinin-producing Monascus
strains. A pksCT-replacement vector (pHD106) was constructed to
disrupt pksCT with a hygromycin resistance gene as the selection
marker, and was transformed into M. aurantiacus Li AS3.4384.
Three transformants (M. aurantiacus PHDS18, PHDS26, PHDS31) were
selected from transformant selective plates. The targeting
fragment D was gained by genomic PCR from PHDS18 and PHDS26
except PHDS31. The expressing citrinin capacities of PHDS26 was
decreased by about 98%, while PHDS18 was reserved the high
capacity of producing citrinin, after 10 days of growth on YM
medium. The results indicated that PHDS26 is a pksCT-disrupted
strain. There are maybe other genes besides pksCT responsible
for citrinin biosynthesis in M. aurantiacus. It is the effective
way to solve the problem of citrinin in M. aurantiacus products
by constructing replacement vectors to disrupt the genes
responsible for citrinin biosynthesis to reduce the capacity of
expressing citrinin.
PMID: 17392092
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