MSA - Ecology/Pathology
Tarnowski, Tara L. , Ploetz, Randy C. .
Diversity in Colletotrichum gloeosporioides populations causing mango anthracnose exhibit unique host specialization.
Colletotrichum gloeosporioides causes blossom blight, leaf anthracnose and fruit anthracnose on mango, causing severe economic loss each year worldwide. Previous work using RAPD markers suggests that some diversity exists in C. gloeosporioides populations on mango. To further assess population structure of the pathogen causing disease on mango, isolates were collected in 2007-2008 from symptomatic inflorescences, leaves, and fruit from several locations in South Florida. DNA sequence data from three loci, the ITS1-5.8S-ITS2, mating type allele (MAT1-2), and a randomly generated DNA fragment adjacent to a microsatellite locus (pTT5), were used in phylogenetic analysis to generate single locus and multilocus phylogenies. Isolates were resolved into two main clades, one containing most leaf and inflorescence isolates, and one containing most fruit isolates along with isolates from other tropical fruit hosts. Pathogenicity tests were performed to assess differences in virulence of isolates from different clades on inflorescences, leaves, and fruit. Several isolates from each clade were inoculated on developing inflorescences and leaf shoots in the field, and on harvested mature fruit, from cv. ‘Keitt’. Disease severity was rated over time and area under the disease progress curve (AUDPC) measurements used in ANOVA analysis. Results indicate that significant differences exist in virulence between the populations. This study shows that populations exist in C. gloeosporioides that are specialized pathogens of different host organs. This knowledge advances our understanding of the diversity and complexity within the C. gloeosporioides species complex. Identifying specialized populations within the pathogen clarifies the epidemiology of the disease and assists in disease management.
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1 - University of Florida, Plant Pathology, Tropical Research and Education Center, 18905 SW 280th ST, Homestead, Florida, 33031, USA
2 - University of Florida, Plant Pathology (Tropical Research and Education Center), PO Box 111569, Homestead, Florida, 330313314, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood B/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 11:15 AM