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Title: PHYLOGENETIC STUDIES OF CORN AND RICE STRAINS OF ACIDOVORAX AVENAE SUBSP. AVENAE BY DNA/DNA HYBRIDIZATION

Author
item POSTNIKOVA, ELENA - UNIV. NEBRASKA
item Schaad, Norman

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2002
Publication Date: 6/1/2002
Citation: POSTNIKOVA, E., SCHAAD, N.W. PHYLOGENETIC STUDIES OF CORN AND RICE STRAINS OF ACIDOVORAX AVENAE SUBSP. AVENAE BY DNA/DNA HYBRIDIZATION. Phytopathology. 92:S66. 2002.

Interpretive Summary:

Technical Abstract: Acidovorax avenae subsp. avenae (Aaa) is the causal agent of diseases of several important economic crops, including bacterial streak of corn (Zea mays) and bacterial stripe of rice (Oryza sativa). To determine the phylogenetic relationship of these two pathogens, a highly reproducible S1 exonuclease DNA/DNA hybridization technique was used. DNA was purified by a modified Marmur method and only DNA with an 260/280 absorbence ratio of 1.8 or greater was used. DNA of the neopathotype strain from corn (ATCC 19860) and a rice strain (ATCC 19882) were labeled with sup33/sup P. Unlabelled DNA was used from six strains from each of corn and rice of different origins, including the United States, India, Japan, and Nigeria. Homologies between strains originating from the same two hosts were very high; 95-99 percent (%) for corn and 87-97 percent (%) for rice. Comparisons of strains between the two pathogenic groups revealed a mean homology of 45 percent (%) (range 42 - 58). Based on a species requirement of 70 percent (%) homology or greater, these results show that the A. avenae pathogens from corn and rice should be reclassified as separate species.