Assessment of Diversity in Claviceps africana and Other Claviceps Species by RAM and AFLP Analyses

Abstract

Genetic diversity among isolates of Claviceps africana, the sorghum ergot pathogen, and isolates of other Claviceps spp. causing ergot on sorghum or other hosts, was analyzed by random amplified microsatellite (RAM) and amplified fragment length polymorphism (AFLP) analyses. Of the RAM primer sets tested, one revealed polymorphism in C. africana isolates, with Australian and Indian isolates possessing a unique fragment. AFLP analysis, in addition to clearly distinguishing Claviceps spp., revealed polymorphisms in C. africana. A group of isolates from the United States, Puerto Rico, and South Africa exhibited 95 to 100% similarity with one another. Several isolates from Isabela, Puerto Rico were 100% similar to an isolate from Texas, and another isolate from Puerto Rico was identical with one from Nebraska. Australian and Indian isolates showed greater than 90% similarity with isolates from the United States., Puerto Rico, and South Africa. A number of polymorphisms existed in the United States group, indicating that the recently introduced population contains multiple genotypes. Isolates of C. sorghicola, a newly described sorghum pathogen from Japan, were very distinct from other species via RAM and AFLP analyses, as were isolates from outgroups C. purpurea and C. fusiformis. Both RAM and AFLP analysis will be useful in determining future patterns of intercontinental migration of the sorghum ergot pathogen, with the AFLP method showing greater ability to characterize levels of intraspecific variation.

Analysis of genetic and aflatoxin diversity among Aspergillus flavus isolates collected from sorghum seeds

“…ISSR markers traditionally show a higher level of polymorphism than RAPD markers and have been used extensively in fungal population analysis . Using ISSR fingerprints, genetic diversity has been observed and reported for previous studies of A. flavus as well as A. terreus . Similar to our observed ITS haplotype association, analysis of ISSR patterns within our sample population revealed the presence of two main clusters.…”

Analysis of molecular diversity in Crinipellis perniciosa with AFLP markers

“…Amplified fragment length polymorphism (AFLP) markers have been used to genetically characterize plant, nematode, bacterial, and fungal populations (Majer et al, 1996;Tooley et al, 2000). AFLPs are thought to be selectively neutral, are usually inherited in a Mendelian fashion, and are more reproducible between laboratories than RAPDs (Jones et al, 2002).…”

Molecular identification and characterization of Fusarium spp. associated with wheat grains

“…The ISSR method is a robust PCRbased technique that produces dominant molecular markers by DNA amplification of putative microsatellite regions (Zietkiewicz et al, 1994). ISSR markers showed a higher level of polymorphism than RAPD markers (Esselman et al, 1999) and have been used extensively in fungal population analysis (Tooley et al, 2000). Three ISSR markers were used to characterize 19 F. verticillioides isolates in terms of their genetic variability and their mycotoxigenic profiles.…”