Extracellular vesicles carry cellulases in the industrial fungus Trichoderma reesei

Abstract

Background Trichoderma reesei is the most important industrial producer of lignocellulolytic enzymes. These enzymes play an important role in biomass degradation leading to novel applications of this fungus in the biotechnology industry, specifically biofuel production. The secretory pathway of fungi is responsible for transporting proteins addressed to different cellular locations involving some cellular endomembrane systems. Although protein secretion is an extremely efficient process in T. reesei , the mechanisms underlying protein secretion have remained largely uncharacterized in this organism. Results Here, we report for the first time the isolation and characterization of T. reesei extracellular vesicles (EVs). Using proteomic analysis under cellulose culture condition, we have confidently identified 188 vesicular proteins belonging to different functional categories. Also, we characterized EVs production using transmission electron microscopy in combination with light scattering analysis. Biochemical assays revealed that T. reesei extracellular vesicles have an enrichment of filter paper (FPase) and β-glucosidase activities in purified vesicles from 24, 72 and 96, and 72 and 96 h, respectively. Furthermore, our results showed that there is a slight enrichment of small RNAs inside the vesicles after 96 h and 120 h, and presence of hsp proteins inside the vesicles purified from T. reesei grown in the presence of cellulose. Conclusions This work points to important insights into a better understanding of the cellular mechanisms underlying the regulation of cellulolytic enzyme secretion in this fungus. Electronic supplementary material The online version of this article (10.1186/s13068-019-1487-7) contains supplementary material, which is available to authorized users.

Extracellular Vesicles in Fungi: Past, Present, and Future Perspectives

“…Compared to yeasts, little is known about EVs in filamentous fungi. However, their presence has been described in different species, including Trichoderma reesei , a fungus involved in lignocellulosic degradation (de Paula et al, 2019 ), in the phytopathogens Alternaria infectoria (Silva et al, 2014 ) and Fusarium oxysporum f. sp. vasinfectum (Bleackley et al, 2019b ), and in the dermatophyte Trichophyton interdigitale (Bitencourt et al, 2018 ).…”

Extracellular Vesicles from Aspergillus flavus Induce M1 Polarization In Vitro

“…In 2007, Rodrigues et al, studying Cryptococcus neoformans, initially reported production of EVs by fungi (15). Since then, fungal EV production has been described in several fungal species, such as Cryptococcus gattii (16), Saccharomyces cerevisiae (17), Alternaria infectoria (18), Paracoccidioides brasiliensis (19), Histoplasma capsulatum (20), Candida albicans (20), Candida parapsilosis (20), Sporothrix schenckii (20), Sporothrix brasiliensis (21), Malassezia sympodialis (22), Pichia fermentans (23), Trichophyton interdigitale (24), Trichoderma reesei (25), Aspergillus fumigatus (26), and others.…”

Intracellular accumulation and secretion of hydrophobin-enriched vesicles aid the rapid sporulation of molds

“…However, Winandy et al 42 showed a similar stability of layers formed on glass by HFBs from both classes, and Hähl et al 61 demonstrated the stability of HFB vesicles formed by HFB1 (class II). Therefore, we speculate that HFBs, as universal and specific fungal proteins, contribute to the formation of extracellular vesicles that attract attention in cell biology as intracellular delivery and communication vehicles 62, as demonstrated in fungi 63 , including Trichoderma 64 .…”