Histone Acetyltransferase Rtt109 Regulates Development, Morphogenesis, and Citrinin Biosynthesis in Monascus purpureus

Abstract

Histone acetyltransferase (HAT) has been reported to be pivotal for various physiological processes in many fungi. However, the functions that HAT Rtt109 perform in edible fungi Monascus and the underlying mechanism remains unclear. Here, we identified the rtt109 gene in Monascus, constructed the rtt109 knockout strain (Δrtt109) and its complementary strain (Δrtt109:com) by CRISPR/Cas9 methods, and functionally characterized the roles that Rtt109 play in Monascus. Deletion of rtt109 significantly reduced conidia formation and colony growth, whereas, it increased the yield of Monascus pigments (MPs) and citrinin (CTN). Further real-time quantitative PCR (RT-qPCR) analysis indicated that Rtt109 remarkably affected the transcriptional expression of key genes related to development, morphogenesis, and secondary metabolism of Monascus. Together, our results revealed the critical roles of HAT Rtt109 in Monascus, and enriched our current knowledge of the development and regulation of secondary metabolism in fungi, throwing light on restraining or eliminating citrinin in the development and industrial applications of Monascus.

COMPASS core subunits MpSet1 and MpSwd3 regulate Monascus pigments synthesis in Monascus purpureus

“…Similarly, the loss of MrHOS3, coding for a histone deacetylase, had increased acetylation levels and MP and citrinin synthesis [45]. Loss of MpRTT109, coding for a histone acetyltransferase, resulted in the growth and development of the strain but derepressed the transcription of MSGs and increased MPs synthesis [33]. Loss of MpASH2, coding for a histone methyltransferase, resulted in growth and reduced MPs synthesis [46].…”

“…The mycelial tissue was ground with liquid nitrogen and mixed with 3 mL of 70% alcohol to detect intracellular MPs synthesis. Both these mixtures were placed in a 60°C water bath for 60 min, and the OD 505 , OD 448 , and OD 410 values were recorded and multiplied by the dilution ratios to determine the MPs content [33].…”

“…MPs are divided into red (505 nm), yellow (410 nm), and orange (448 nm) pigments [33,35]. Therefore, the extracellular and intracellular pigments were tested to investigate whether MpSet1 and MpSwd3 affect pigment synthesis.…”

Effect of Exogenous and Endogenous Ectoine on Monascus Development, Metabolism, and Pigment Stability

“…The construction of the M. purpureus ectoine-producing strain (MppECT) was performed as described by Shi et al [21]. The pBARGPE-hygro-ectABC plasmid was incubated with 100 µL of M. purpureus ATCC 16365 WT strain protoplasts to construct the ectoineproducing strain (MppECT).…”

“…For the extraction of CTN, the method described by Shi et al [21] was employed. The CTN concentration in the fermentation broth was determined using ultra-performance liquid chromatography (UPLC) with an Agilent 1290 system (Waldbronn, Germany).…”