Influences of genetically perturbing synthesis of the typical yellow pigment on conidiation, cell wall integrity, stress tolerance, and cellulase production in Trichoderma reesei

Dual Regulatory Role of Chromatin Remodeler ISW1 in Coordinating Cellulase and Secondary Metabolite Biosynthesis in Trichoderma reesei

“…S7 ), indicating that the observed enhanced sorbicillinoid production resultant from Trisw1 deletion necessitates YPR1, the deregulation of which may contribute to the elevated expression of the sor cluster. It has been shown that hyperproduction of the yellow pigment severely compromised extracellular cellobiohydrolase production ( 36 ). However, analysis of the extracellular hydrolytic activities of the two double deletion mutants revealed that elimination of the pigment did not ameliorate the defective cellulase induction ( Fig.…”

“…Meanwhile, T. reesei can also produce a large amount of yellow pigment identified as a mixture of secondary metabolites with various bioactivities during cultivation ( 34 , 35 ). Whereas it has been shown that hyper-production of sorbicillinoids is correlated with the dramatically reduced cellulase gene expression ( 36 , 40 ), the involved regulatory mechanism that guarantees the subtle balance between cellulolytic response and sorbicillinoid biosynthesis is not clear in T. reesei . In this study, we found that TrISW1, the ATPase subunit of the ISWI complex, differentially participated in regulating the expression of cellulase genes and the gene cluster responsible for the yellow pigment biosynthesis in T. reesei .…”

“…On one hand, TrISW1 acts as a repressor to set a brake on the sorbicillinoid biosynthetic gene transcription to maintain its relatively low-level expression. With cultivation, the inhibition exerted by TrISW1 is somehow released to allow the gradually accumulated sorbicillinoid production ( 36 ). On the other hand, TrISW1 is recruited to cellulase gene promoters on cellulase induction to facilitate the formation of a potentially more open chromatin environment, which contributes to the successful initiation of cellulase gene expression.…”

“…While YPR1 is considered to be the transcriptional activator for the expression of most genes within the cluster, YPR2 acts as a repressor that negatively regulates the expression of the ypr1 and sor genes ( 35 ). Although the exact mechanism by which YPR1 and YPR2 regulate the sor expression is not clear at present, it has been found that excessive formation of the yellow pigment dramatically interferes with the induced cellulase gene expression ( 36 ).…”

Heterologous Expression of Secondary Metabolite Genes in Trichoderma reesei for Waste Valorization

“…Secondly, the high levels of sorbicillinoids in the extract complicate the isolation of desired metabolites. Finally, recent studies have shown negative effects of sorbicillinoid production on growth, conidiation, cell wall integrity and cellulase production in T. reesei [2,44]. Therefore, a T. reesei strain lacking sorbicillin synthesis was desired.…”