Diversity, structure, and synteny of the cutinase gene of Colletotrichum species

• Published in: Ecology and evolution Vol. 10; no. 3; pp. 1425 - 1443
• Main Authors: Villafana, Ria T., Rampersad, Sephra N.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.02.2020; John Wiley and Sons Inc; Wiley
• Subjects: Agricultural commodities; Alternative splicing; Amino acids; Anthracnose; Bioassays; Biosynthesis; Cluster analysis; Colletotrichum; Cutinase; cutinase diversity; Disease hot spots; Elongation; Enzymes; evolution; Exons; Fruits; Fungi; Gene duplication; Gene expression; Genetic engineering; Haplotypes; Host plants; Hsp70 protein; Infections; Kinases; Lipids; Low level; Nucleotides; Original Research; pathogenesis; Pathogens; Peppers; Physiology; Positive selection; Proteins; Recombination; Ribonucleic acid; RNA; Speciation; Species; Species diversity; Substrates; Synteny; Translation elongation; Asia; China; pathogenesis; cutinase diversity; evolution; Colletotrichum; synteny
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.5998

Colletotrichum species complexes are among the top 10 economically important fungal plant pathogens worldwide because they can infect climacteric and nonclimacteric fruit at the pre and/or postharvest stages. C. truncatum is the major pathogen responsible for anthracnose of green and red bell pepper fruit worldwide. C. brevisporum was recently reported to be a minor pathogen of red bell pepper fruit in Trinidad, but has recently been reported as pathogenic to other host species in other countries. The ability of these phytopathogens to produce and secrete cutinase is required for dismantling the cuticle of the host plant and, therefore, crucial to the necrotrophic phase of their infection strategy. In vitro bioassays using different lipid substrates confirmed the ability of C. truncatum and C. brevisporum isolates from green and red bell peppers to secrete cutinase. The diversity, structure and organization and synteny of the cutinase gene were determined among different Colletotrichum species. Cluster analysis indicated a low level of nucleotide variation among C. truncatum sequences. Nucleotide sequences of C. brevisporum were more related to C. truncatum cutinase nucleotide sequences than to C. gloeosporioides. Cluster patterns coincided with haplotype and there was evidence of significant positive selection with no recombination signatures. The structure of the cutinase gene included two exons with one intervening intron and, therefore, one splice variant. Although amino acid sequences were highly conserved among C. truncatum isolates, diversity “hot spots” were revealed when the 66‐amino acid coding region of 200 fungal species was compared. Twenty cutinase orthologues were detected among different fungal species, whose common ancestor is Pezizomycotina and it is purported that these orthologues arose through a single gene duplication event prior to speciation. The cutinase domain was retained both in structure and arrangement among 34 different Colletotrichum species. The order of aligned genomic blocks between species and the arrangement of flanking protein domains were also conserved and shared for those domains immediately located at the N‐ and C‐terminus of the cutinase domain. Among these were an RNA recognition motif, translation elongation factor, signal peptide, pentatricopeptide repeat, and Hsp70 family of chaperone proteins, all of which support the expression of the cutinase gene. The findings of this study are important to understanding the evolution of the cutinase gene in C. truncatum as a key component of the biotrophic–necrotrophic switch which may be useful in developing gene‐targeting strategies to decrease the pathogenic potential of Colletotrichum species. Low sequence diversity and high evolutionary conservation of the cutinase gene in Colletotrichum truncatum are key to this phytopathogen's infection strategy.