Chitinolytic Enzymes of the Hyperparasite Fungus Aphanocladium album : Genome-Wide Survey and Characterization of A Selected Enzyme

• Published in: Microorganisms (Basel) Vol. 11; no. 5; p. 1357
• Main Authors: Leoni, Claudia, Manzari, Caterina, Chiara, Matteo, Veronico, Pasqua, Bruno, Giovanni Luigi, Pesole, Graziano, Ceci, Luigi R, Volpicella, Mariateresa
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22-05-2023; MDPI
• Subjects: Annotations; Aphanocladium album; Carbohydrates; Chitinase; Cloning; Clustering; Enzymes; Fungi; Fungicidal activity; Fungicides; Genes; genome sequencing; Genomes; mycoparasite; Nucleotide sequence; Pathogens; Phylogenetics; Phylogeny; Plant diseases; Plant protection; Polypeptides; Proteins; Software; Subgroups; Substrates; Yeasts; United States > US; Aphanocladium album; genome sequencing; chitinase; mycoparasite; plant protection
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms11051357

The filamentous fungus
is known as a hyperparasite of plant pathogenic fungi; hence, it has been studied as a possible agent for plant protection. Chitinases secreted by
have proven to be essential for its fungicidal activity. However, no complete analysis of the
chitinase assortment has been carried out, nor have any of its chitinases been characterized yet. In this study, we report the first draft assembly of the genome sequence of
(strain MX-95). The in silico functional annotation of the genome allowed the identification of 46 genes encoding chitinolytic enzymes of the GH18 (26 genes), GH20 (8 genes), GH75 (8 genes), and GH3 (4 genes) families. The encoded proteins were investigated by comparative and phylogenetic analysis, allowing clustering in different subgroups.
chitinases were also characterized according to the presence of different functional protein domains (carbohydrate-binding modules and catalytic domains) providing the first complete description of the chitinase repertoire of
. A single chitinase gene was then selected for complete functional characterization. The encoded protein was expressed in the yeast
, and its activity was assayed under different conditions of temperature and pH and with different substrates. It was found that the enzyme acts mainly as a chitobiosidase, with higher activity in the 37-50 °C range.