Cloning and characterization of chitin synthase gene fragments from Penicillium chrysogenum

Survey of the Botrytis cinerea chitin synthase multigenic family through the analysis of six euascomycetes genomes

We describe a strategy for systematic amplification of chitin synthase genes (chs) in the filamentous ascomycetes plant-pathogen Botrytis cinerea using PCR with multiple degenerate primers designed on specific and conserved sequence motifs. Eight distinct chs genes were isolated, named Bcchs I, II, IIIa, IIIb, IV, V, VI and VII. They probably constitute the entire chs multigenic family of this fungus, as revealed by careful analysis of six euascomycetes genomes. Bcchs I, IIIa, IIIb, IV and VI genes were subjected to DNA walking and their deduced amino acid sequences were compared by hydrophobic cluster analysis (HCA) to localize putative residues critical for CHS activity. HCA also enabled us to highlight three different transmembrane topologies of the CHS membranous isoenzymes. We found that the N-terminal region of the BcCHSI isoenzyme, and its orthologues in other euascomycetes, probably contain folded peptide motifs with conserved tyrosine residues. Their putative role is discussed. The BcCHSVII isoenzyme appeared to belong to a new class of CHS orthologues that was demonstrated by phylogenetic study to branch apart from division 1 and 2 of CHS.

Cloning and phylogenetic analysis of chitin synthase genes from the insect pathogenic fungus, Metarhizium anisopliae var. anisopliae

Degenerated PCR primers were used to amplify chitin synthase genes from genomic DNA of Metarhizium anisopliae var. anisopliae. Through cloning and sequencing of approximately 600-bp fragments amplified by PCR, we found three genes encoding different types of chitin synthases, designated MaCHS1, MaCHS2, and MaCHS3. Southern blot analysis performed on genomic DNA showed that each of the chitin synthases MaCHS1, MaCHS2, and MaCHS3 is encoded by a single copy gene. Alignment of their deduced amino acid sequences with those of other euascomycetes separated the sequences into three distinct classes. MaCHS1 was identified as a gene for class I chitin synthase, MaCHS2 for class II, and MaCHS3 for class III. The UPGMA dendrogram and phylogenetic tree of the deduced amino acid sequences revealed the taxonomic and evolutionary position of Metarhizium anisopliae var. anisopliae.