Mphy gene is involved in temperature-regulated pigment metabolism in Monascus

In plant, Phytochrome (phy) as a light receptor not only plays an important effect on plant morphogenesis, but also is involved in the regulation of plant defense resistance. In Monascus, the formation of conidia, cleistothecia and types and yields of secondary metabolites were found to influence by environmental conditions such as light, temperature, pH, etc. However, the underlying mechanism has not been revealed. Here, the effects of Monascusphy (Mphy) on the regulation of temperature on the growth and development and pigments biosysnthesis of Monascus were investigated by disruption and overexpression of Mphy gene. Colony diameter and number of spores of Mphy knock out strain (ΔMphy) and overexpression strain (OE-Mphy) are reduced compared with the wild strain. The yellow, orange and red pigments yields of original strain was 1.1, 1.2 and 1.1times that of OE-phy strain, and 13.4, 19.3, and 15.2 times that of ΔMphy strain, respectively at 25°C. At 30°C, the yellow, orange and red pigment yields of original strain was 1.3, 1.3 and 1.2 times that of OE-phy strain, and 2.4, 3.7, and 3.0 times that of ΔMphy strain, respectively. However, at 35°C, OE-phy strain had the highest pigment yield, and the pigment yield of the original strain and the ΔMphy strain were very similar. HPLC results showed that the pigment types of primitive strain and OE-phy strain were mainly yellow and orange pigments, and the ΔMphy strain was mainly yellow pigments at 25°C. At 30°C, the original strain had more red, yellow and orange pigments, the OE-phy strain was mainly red and yellow pigments, and the ΔMphy strain was mainly yellow pigments. At 35°C, red and yellow pigments were predominant in the original strain and OE-phy strain, while yellow pigments were predominant in ΔMphy strain.