Genetic Variation Among Colletotrichum graminicola Isolates from Four Hosts Using Isozyme Analysis

Abstract

Anthracnose basal rot (ABR) is a serious disease of turfgrasses that is caused by the pathogen Colletotrichum graminicola. The relationships of isolates causing ABR on turfgrasses to those causing disease on important crop hosts (maize, sorghum) remain unresolved. Genetic variation among isolates from annual bluegrass, creeping bentgrass, maize, and sorghum was evaluated based on host origin and geographic origin. Isozymes were used to estimate the genetic variation of the isolates. Five enzyme systems comprising 16 alleles from 5 loci were used. Allele frequencies, genetic distance, and linkage disequilibrium values were calculated for isolates based on both host and geographic origin. Isolates from creeping bentgrass and annual bluegrass were the most closely related based on Nei's genetic distance, while isolates from maize and sorghum were the most distantly related, consistent with their known species-level relationship. Isolates from annual bluegrass and creeping bentgrass had different genetic distances to isolates from both maize and sorghum. Annual bluegrass isolates from different geographic regions had the smallest genetic distance values observed in this study, indicating a very close relationship regardless of geographic origin. Based on these data, it appears that host origin, not geographic origin, plays a more important role in the genetic diversity of these fungi.

Molecular Analysis in the differentiation of Colletotrichum gloeosporioides isolates from the cashew and mango trees

“…1), demonstrating strict uniformity between the isolates from the cashew in the enzyme systems studied. In C. graminicola, Horvath and Vargas Jr. (2004) * CMA (cashew tree-MA), CPE (cashew tree-PE), CPB (cashew tree-PB), MMA (mango tree-MA), MPE (mango tree-PE), MPB (mango tree-PB).…”

Unraveling Evolutionary Relationships Among the Divergent Lineages of Colletotrichum Causing Anthracnose Disease in Turfgrass and Corn

“…Several conflicting hypotheses were proposed concerning the evolution and diversity of C. graminicola, but no theory has generally been accepted as an accurate representation of the species history. Molecular data were used to suggest a close connection between C. sublineolum and isolates of Colletotrichum causing anthracnose in annual bluegrass turf (6,30), whereas another study supported an association between isolates from creeping bentgrass turf and those from corn (6). Results from other research groups supported a separate lineage of turfgrass pathogens, diverged from corn and sorghum isolates, which share a single ancestor (12,19,25,31).…”

Patterns of Diversity in Populations of the Turfgrass Pathogen Colletotrichum cereale as Revealed by Transposon Fingerprint Profiles

“…Because genetic variability between isolates of C. cereale may influence the trajectory of anthracnose disease of turfgrass, a comprehensive understanding of how C. cereale populations are organized and distributed across their geographic range could enhance the development and implementation of effective disease management strategies. At present only limited population‐level data, derived from randomly amplified polymorphic DNA (RAPD) or isozyme markers, are available for the fungus (Backman et al, 1999; Browning et al, 1999; Chen et al, 2002; Horvath and Vargas, 2004), although two major lineages, designated clades A and B, have been recognized on the basis of intergenic transcribed spacer (ITS) nucleotide sequences (Crouch et al, 2005) and a multiple gene genealogical approach (Crouch et al, 2006). Currently, few apparent biological patterns are readily ascribable to this divergence, and uncertainty exists as to whether the two groups are genetically isolated.…”