Author
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Dunkle, Larry |
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LIPPS, P - OHIO STATE UNIVERSITY |
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Submitted to: Phytopathology
Publication Type: Abstract Only Publication Acceptance Date: 8/27/2001 Publication Date: 8/27/2001 Citation: DUNKLE, L.D., LIPPS, P.E. PHENOTYPIC VARIABILITY IN CERCOSPORA ZEAE-MAYDIS. PHYTOPATHOLOGY. 2001. Interpretive Summary: Technical Abstract: In the USA, gray leaf spot (GLS) of maize is caused by two genetically distinct forms of Cercospora zeae-maydis: Group I, faster growing isolates that produce cercosporin in culture (F+); and Group II, slower-growing isolates that do not produce detectable amounts of cercosporin (S-). We analyzed single-spore isolates from individual lesions collected from a field in Apple Creek, OH, where both groups have been sympatric for >5 years. Of 175 lesions, 77% yielded F+ isolates and 9% yielded S-. The remaining 14% yielded mixed phenotypes, including an intermediate phenotype (I+), which grew slower (0.6X) than F+ but faster (1.4X) than S- and produced cercosporin 4-6 days later than F+ isolates. A series of monoconidial isolates derived from I+ cultures repeatedly yielded a mixture of phenotypes. RFLP analysis of the ITS regions of rDNA and AFLP analyses failed to indicate that the I+ cultures were heterokaryotic. AFLP profiles of I+ revealed several variable loci in a profile that was otherwise identical to that of F+. Consequences of this phenotypic variability on GLS severity were not determined. |
