Stress-Activated Protein Kinase Signalling Regulates Mycoparasitic Hyphal-Hyphal Interactions in Trichoderma atroviride

et al. 2022

JoF

The nature of saprophytic and mycoparasitic hyphal growth of Trichoderma spp. has been studied extensively, yet its initiation via conidial germination in this genus is less well understood. Using near-synchronous germinating cultures of Trichoderma asperelloides, we followed the morphological progression from dormant conidia to initial polar growth to germling formation and to evidence for first branching. We found that the stage-specific transcriptional profile of T. asperelloides is one of the most dynamic described to date: transcript abundance of over 5000 genes—comprising approximately half of the annotated genome—was unremittingly reduced in the transition from dormancy to polar growth. Conversely, after the onset of germination, the transcript abundance of approximately a quarter of the genome was unremittingly elevated during the transition from elongation to initial branching. These changes are a testimony to the substantial developmental events that accompany germination. Bayesian network analysis identified several chitinase- and glucanase-encoding genes as active transcriptional hubs during germination. Furthermore, the expression of specific members of the chitin synthase and glucan elongase families was significantly increased during germination in the presence of Rhizoctonia solani—a known host of the mycoparasite—indicating that host recognition can occur during the early stages of mycoparasite development.

Section: Discussionsupporting

confidence: 91%

Differential Expression of Cell Wall Remodeling Genes Is Part of the Dynamic Phase-Specific Transcriptional Program of Conidial Germination of Trichoderma asperelloides

Gortikov

Yakubovich

et al. 2022

JoF

“…The mycoparasitism process of T. harzianum involves a series of activities such as recognition, adherence, attachment, persistence, hydrolysis and parasitism of the host hyphae at different growth stages [ 31 ]. In this regard, MAPK and G protein have been proven to be involved in the recognition and attachment stages of mycoparasitism [ 18 , 32 ]. Recent studies have shown that MAPK participates in the formation of cellulase and regulates its expression at the transcription level [ 33 , 34 , 35 ].…”

Section: Discussionmentioning

confidence: 99%

Identification of Mycoparasitism-Related Genes against the Phytopathogen Botrytis cinerea via Transcriptome Analysis of Trichoderma harzianum T4

Zhu

et al. 2023

JoF

Trichoderma harzianum is a well-known biological control agent (BCA) that is effective against a variety of plant pathogens. In previous studies, we found that T. harzianum T4 could effectively control the gray mold in tomatoes caused by Botrytis cinerea. However, the research on its biocontrol mechanism is not comprehensive, particularly regarding the mechanism of mycoparasitism. In this study, in order to further investigate the mycoparasitism mechanism of T. harzianum T4, transcriptomic sequencing and real-time fluorescence quantitative PCR (RT-qPCR) were used to identify the differentially expressed genes (DEGs) of T. harzianum T4 at 12, 24, 48 and 72 h of growth in the cell wall of B. cinerea (BCCW) or a sucrose medium. A total of 2871 DEGs and 2148 novel genes were detected using transcriptome sequencing. Through GO and KEGG enrichment analysis, we identified genes associated with mycoparasitism at specific time periods, such as encoding kinases, signal transduction proteins, carbohydrate active enzymes, hydrolytic enzymes, transporters, antioxidant enzymes, secondary metabolite synthesis, resistance proteins, detoxification genes and genes associated with extended hyphal longevity. To validate the transcriptome data, RT-qCPR was performed on the transcriptome samples. The RT-qPCR results show that the expression trend of the genes was consistent with the RNA-Seq data. In order to validate the screened genes associated with mycoparasitism, we performed a dual-culture antagonism test on T. harzianum and B. cinerea. The results of the dual-culture RT-qPCR showed that 15 of the 24 genes were upregulated during and after contact between T. harzianum T4 and B. cinerea (the same as BCCW), which further confirmed that these genes were involved in the mycoparasitism of T. harzianum T4. In conclusion, the transcriptome data provided in this study will not only improve the annotation information of gene models in T. harzianum T4 genome, but also provide important transcriptome information regarding the process of mycoparasitism at specific time periods, which can help us to further understand the mechanism of mycoparasitism, thus providing a potential molecular target for T. harzianum T4 as a biological control agent.

“…In T. atroviride, lack of Tmk1 reduced mycoparasitic activity, yet higher antifungal activity attributed to low molecular weight substances including 6-pentyl-α-pyrone (6PP) and peptaibol antibiotics 71 . Recently, T. atroviride Tmk3 and Tmk1 were implicated in polarity stress response during hyphal interaction upon mycoparasitism and the chemotropic interaction between individual hyphae in this process 72 . Another case of antagonism was shown for T. atroviride with Drosophila melanogaster larvae, which fed on the fungal mycelium.…”

Section: Introductionmentioning

confidence: 99%

MAPkinases regulate secondary metabolism, sexual development and light dependent cellulase regulation in Trichoderma reesei

Schalamun

Beier

Hinterdobler

et al. 2022

Preprint

The filamentous fungus Trichoderma reesei is a prolific producer of plant cell wall degrading enzymes, which are regulated in response to diverse environmental signals for optimal adaptation, but also produces a wide array of secondary metabolites. Available carbon source and light are the strongest cues currently known to impact secreted enzyme levels and an interplay with regulation of secondary metabolism became increasingly obvious in recent years. While cellulase regulation is already known to be modulated by different mitogen activated protein kinase (MAPK) pathways, the relevance of the light signal, which is transmitted by this pathway in other fungi as well, is still unknown in T. reesei as are interconnections to secondary metabolism and chemical communication under mating conditions. Here we show that MAPkinases differentially influence cellulase regulation in light and darkness and that the Hog1 homologue TMK3, but not TMK1 or TMK2 are required for the chemotropic response to glucose in T. reesei. Additionally, MAPkinases regulate production of specific secondary metabolites including trichodimerol and bisorbibutenolid, a bioactive compound with cytostatic effect on cancer cells and deterrent effect on larvae, under conditions facilitating mating, which reflects a defect in chemical communication. Strains lacking either of the MAPkinases become female sterile, indicating the conservation of the role of MAPkinases in sexual fertility also in T. reesei. In summary, our findings substantiate the previously detected interconnection of cellulase regulation with regulation of secondary metabolism as well as the involvement of MAPkinases in light dependent gene regulation of cellulase and secondary metabolite genes in fungi.