Identification of the role of a MAP kinase Tmk2 in Hypocrea jecorina (Trichoderma reesei)

Abstract

Despite the important role of MAPKs in signal transduction, their functions in the cellulase hyper-producing filamentous fungus Hypocrea jecorina haven't been studied except for the Hog1-like Tmk3. In this work, we constructed and explored the features of H. jecorina Δtmk2 to identify the role of this Slt2-homologous Tmk2. It is suggested from the results that Tmk2 is involved in cell wall integrity, sporulation and cellulase production. Although bearing similar roles in cell wall integrity maintenance, Tmk2 and Tmk3 appear to also have distinct functions: Tmk3 participates in high osmolarity resistance while Tmk2 does not; Tmk2 participates in sporulation but not Tmk3; Tmk3 is involved in promoting cellulase production while Tmk2 is involved in repressing cellulase formation. These studies provide the first insight into the function of Tmk2 in H. jecorina and contribute to understanding the signal transduction processes leading to the regulation of cellulase production in this important cellulase hyper-producer.

Role of Trichoderma reesei mitogen-activated protein kinases (MAPKs) in cellulase formation

“…5). T. reesei TU-6 was able to tolerate 200 mg L −1 CR and 20 mg L −1 CFW, while T. reesei Δtmk2 cannot, suggesting that tolerance to CR and CFW is reduced in T. reesei Δtmk2 in comparison with the parent T. reesei TU-6 strain, in agreement with the previous report [59]. By overexpressing tmk3 , this tolerance is regained, suggesting restoration of cell wall integrity in comparison with T. reesei Δtmk2 (Fig.…”

“…6b–e). From these transcriptional analyses, suggestions can be made that the deletion of tmk2 and subsequent overexpression of tmk3 do not lead to changes in the transcriptional levels of cellulase-coding genes, in agreement with the previous reports [59].

Fig.

…”

“…Previous research carried out in our laboratory has shown the physiological functions of Tmk2 and Tmk3 [15, 59]. Our results showed that both Tmk2 and Tmk3 are involved in cell wall integrity maintenance.…”

Introduction of theAspergillus fumigatusα-1,2-mannosidase MsdS intoTrichoderma reeseileads to abnormal polarity and improves the ligno-cellulose degradation

“…Filamentous fungi are thought as the most efficient lignocelluloses degraders, especially T. reesei (Zhang et al, 2015; Wang et al, 2014), however, there is still an insufficient hydrolysis of lignocellulose due to the moderately low levels of mannan-degrading activity (Inoue et al, 2015). To compensate for the lower mannan-degrading activity, exogenous mannosidases have been added in the cellulase system.…”

Identificação de alvos de fosforilação de MAPK em <i>Trichoderma reesei</i> através de fosfoproteômica durante a produção de celulases

“…A alta concentração de AMPc estimula a ativação da PKA, desencadeando a fosforilação de proteínas envolvidas nos diversos processos celulares já citados (BUDOVSKAYA et al, 2004;MEHRABI et al, 2009;TAMAKI, 2007). As vias de sinalização têm sido extensivamente estudadas em T. reesei, estando envolvidas com diversos processos celulares relacionados com a esporulação e o sensing do ambiente externo, além da produção de enzimas celulolíticas nessa espécie (DE PAULA, 2017;LENDENFELD;KUBICEK, 1998;MORAWETZ et al, 1996;REITHNER et al, 2005;ROCHA-RAMIREZ et al, 2002;SCHMOLL, 2008;SESTAK;FARKAS, 1993;TISCH;SCHMOLL, 2013;WANG et al, 2013bWANG et al, , 2014aZHANG et al, 2012).…”