AUTHOR=Shi Jin-Chao , Shi Wei-Ling , Zhou Yan-Rong , Chen Xiu-Lan , Zhang Yu-Zhong , Zhang Xia , Zhang Wei-Xin , Song Xiao-Yan 

TITLE=The Putative Methyltransferase TlLAE1 Is Involved in the Regulation of Peptaibols Production in the Biocontrol Fungus Trichoderma longibrachiatum SMF2

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.01267

DOI=10.3389/fmicb.2020.01267

ISSN=1664-302X

ABSTRACT=<p>The biocontrol fungus <italic>Trichoderma longibrachiatum</italic> SMF2 secretes a large quantity of peptaibols that have been shown to have a range of biological activities and therefore great application values. However, the mechanism of the regulatory expression of peptaibols is still unclear. The putative methyltransferase LaeA/LAE1 is a global regulator involved in the biosynthesis of some secondary metabolites in filamentous fungi. In this study, we demonstrated that the ortholog of LaeA/LAE1 in the biocontrol fungus <italic>T. longibrachiatum</italic> SMF2, <italic>Tl</italic>LAE1, plays an important role in the regulation of peptaibols production. Deletion of <italic>Tllae1</italic> resulted in a slight negative impact on mycelial growth, and a significant defect in conidial production. Deletion of <italic>Tllae1</italic> also compromised the production of peptaibols to a large degree. Further analyses indicated that this defect occurred at the transcriptional level of the two synthetases-encoding genes, <italic>tlx1</italic> and <italic>tlx2</italic>, which are responsible for peptaibols production. By contrast, constitutive expression of <italic>Tllae1</italic> in <italic>T. longibrachiatum</italic> SMF2 led to 2-fold increased peptaibols production, suggesting that this is a strategy to improve peptaibols production in <italic>Trichoderma</italic> fungi. These results demonstrate the important role of LAE1 in the regulation of peptaibols production in <italic>T. longibrachiatum</italic> SMF2.</p>