Biology subjects

Guillemette, T.

Publications and source records attributed to Guillemette, T..

3 recordsLinked to original sources

bioRxiv2026

Molecular Basis of Mycoparasitic Performance: Genomic and Transcriptomic Comparison of Contrasting Trichoderma atroviride Strains

Trichoderma species are widely used as biological control agents due to their ability to parasitize plant pathogens. However, substantial variability in mycoparasitic performance exists among strains, even within the same species, and the underlying molecular mechanisms remain poorly understood. Here, we performed comparative genomic and transcriptomic analyses of six Trichoderma atroviride strains exhibiting contrasting mycoparasitic performance (weakly or highly parasitic; WP or HP) against Alternaria brassicicola, Rhizoctonia solani, and Globisporangium ultimum. Comparative genomics revealed limited strain-specific differences, mainly restricted to NLR (NOD-like receptor) repertoires, with certain NLR-coding genes absent from WP strain genomes compared to HP strains, while overall genomic variation remained low. In contrast, transcriptomic analyses revealed strong differences in gene expression dynamics between HP and WP strains. Co-expression network analysis identified two modules associated with mycoparasitic performance. The first was specifically induced in response to pathogen contact and was enriched in genes encoding cell wall-degrading enzymes, with stronger expression in HP strains. The second module was more broadly overexpressed in HP strains across all conditions and included genes involved in detoxification and defense-related pathways. In addition, this module encompassed genes involved in specialized metabolite biosynthesis and effector-like protein secretion, with WP and HP strains differentially expressing distinct gene subsets within these categories. Together, these results provide a comprehensive framework for identifying the molecular drivers of mycoparasitic performance in T. atroviride. This study deepens our understanding of the functional diversity within the species and establishes a robust foundation for the future development of molecular markers to predict strain efficiency. Highlights- Significant variability in mycoparasitic performance exists within Trichoderma atroviride. - Certain NLR receptor genes are specific to highly parasitic genomes. - Highly parasitic strains show stronger expression of CWDE, ROS detoxification, and defense-related pathways. - Highly and weakly parasitic strains differ in expressed specialized metabolism and effector-like gene sets.

genomics↗

bioRxiv2025

Draft genome of Trichoderma gamsii strain T035 a promising beneficial fungus in agriculture

AO_SCPLOWBSTRACTC_SCPLOWTrichoderma gamsii is a filamentous fungus widely recognized for its beneficial roles in agriculture, particularly for its ability to suppress plant pathogens and enhance crop health. However, genomic resources for this species remain scarce, limiting functional and applied studies. Here, we report the high-quality genome of T. gamsii strain T035, a promising biocontrol strain with significant antagonistic activity against several pathogens in vitro. The assembly consisted of 16 sequences, including near 7 chromosome-scale sequences, with an N50 value of 7.2 Mbp and a total assembly length of 38.8 Mbp. This genome represents the most complete T. gamsii assembly to date and will provide a valuable resource to facilitate the exploration of molecular mechanisms underlying biocontrol and support the development of sustainable plant protection strategies.

genomics↗

bioRxiv2024

Unexplored Yeast diversity in Seed Microbiota

Yeasts are known to be fantastic biotechnological resources for medical, food, and industrial applications, but their potential remains untapped in agriculture, especially for plant biostimulation and biocontrol. In particular, yeasts have been reported as part of the core microbiome of seeds using next generation sequencing methods, but their diversity and functional roles remain largely undescribed. Focusing on yeasts and excluding filamentous fungi, this study aimed to characterize the diversity of seed-associated yeasts across nine plant species (crops and non-cultivated species) using culturomics and microscopy. Comparison with available metabarcoding data was performed to assess the representativeness of the strain collection in seed samples. Our results show that seed-associated yeasts largely belong to Basidiomycota phylum and more particularly to the Tremellomycetes class. This yeast collection covers 15 genera (2 of Ascomycota and 13 of Basidiomycota). Out of the 229 isolates described, the most frequently isolated yeasts were Holtermanniella, Vishniacozyma, Filobasidium, Naganishia and Sporobolomyces. The yeasts from these dominant genera were isolated from multiple plant species (4 to 8), except for Naganishia which only originated from Solanum lycopersicum L. These results are also consistent with the fact that these dominant taxa were recently identified as members of the core seed microbiome, indicating their high prevalence and abundance across diverse plant hosts and environments. Compared to previous plant yeast diversity surveys, the members from Ascomycota yeasts are less frequent in seeds and only represented here by the Aureobasidium and Taphrina genera. Altogether, these results suggest that yeasts are generally well-adapted to the aboveground habitats of plants, but seeds represent a specific habitat that diverse Basidiomycota yeasts can colonize. Take away messageO_LI229 yeasts isolated from seeds and seedlings of diverse plant species C_LIO_LIMost isolates are Basidiomycota yeasts, especially of the Tremellomycetes class C_LIO_LIThe most frequently isolated yeasts belong to Holtermanniella, Vishniacozyma, Filobasidium and Sporobolomyces genera C_LIO_LIThe collection is representative of taxa found in seed microbiota of multiple plant species, including core members C_LI

microbiology↗