Genome diversity and characterization of Colletotrichum from maize and sorghum
Abstract
Based on mating preference, host-specificity, and DNA fingerprinting, it has been proposed that maize and sorghum pathotypes of the fungus Colletotrichum are different species. My aim was to use molecular-genetics to examine relatedness and speciation in these pathotypes. Though unique RAPD markers were detected, hybridization showed that none corresponded to pathotype-specific genes. Genomic subtraction also failed to yield pathotype-specific sequences. Sequence of rDNA indicated the pathotypes were 99% homologous. Reassociation kinetics confirmed the results from rDNA sequencing. On the basis of these results, it appears that maize and sorghum pathotypes are more closely related than expected. I conclude that Colletotrichum from maize and sorghum belong to the category of a semi-species. On an evolutionary scale, though phenotypically distinct, they have only recently begun to diverge at the level of nucleotide sequence.
Degree
Ph.D.
Advisors
Hanau, Purdue University.
Subject Area
Genetics|Molecular biology|Plant pathology|Microbiology
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