| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1217-1 | ||||
Resumo:Filamentous fungi have the common ability to secrete hydrophobins (HFBs), which are low molecular weight amphiphilic proteins (<20 kDa) characterized by the presence of eight cysteine residues (Cys). These proteins play a crucial role in reducing interfacial tension, allowing hyphae to breach the liquid surface and grow in the air, forming floating colonies. Moreover, they confer water-repellent properties to fungal bodies and spores, influencing spore dispersion, resistance to environmental stresses, interactions with symbiotic partners, as well as fungal growth and development. While most fungi have only a few genes encoding HFBs, the genus Trichoderma stands out for its high number and diversity of these proteins, which have become distinctive genomic features in these fungi. However, the biological and ecological role of HFB enrichment in the Trichoderma genome, as well as the specific function of each HFB, remains incompletely understood. The aim of this study was to assess the expression of genes encoding HFBs at different stages of Trichoderma afroharzianum growth. To study the expression of these genes during the growth of T. afroharzianum, fungal biomass corresponding to four stages of the fungus's life cycle, namely (I) the log-phase growth stage on the substrate (48 h), (II) the onset of aerial hyphae formation (72 h), (III) the reproductive mycelium phase (conidiation) (144 h), and (IV) conidia and spores, were collected from cultures in solid and liquid media in Petri dishes containing potato dextrose with and without agar, respectively. Total RNA from each mycelium and spore sample was extracted from 100 mg of tissue using Bio-zol reagent. After cDNA was synthesized the relative quantification of gene expression levels was performed using the real-time PCR technique following the 2−𝛥𝛥𝐶𝑡 method, using translation elongation factor EF-1 alpha (tef1) as the housekeeping gene. The results showed that two genes for HFBs (hfb2 and hfb4) were highly expressed during reproductive mycelium formation, and hfb4 remained highly active in spores, indicating their involvement in conidiogenesis development. On the other hand, the hfb6 gene exhibited relatively low expression, being predominant in spores, suggesting its role in spore dispersal, while the expression of other genes was not observed. Additionally, we observed that most HFBs genes had low relative expression values during the formation of trophic hyphae (submerged growth), except for hfb2, which also showed activity at this stage, indicating its participation in other functions, possibly linked to the response to oxidative stress. These findings provide valuable insights into the role of hydrophobins in the life cycle of Trichoderma and their specific expressions during different growth stages, enhancing our understanding of their biological and ecological functions. Palavras-chave: Trichoderma, hydrophobins, gene expression, real time PCR Agência de fomento:Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) | |||||