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Pathogenic and molecular variability and telia production of Uromyces appendiculatus isolates from the Andean and Middle American centers of domestication of common bean
Abstract
The pathogenic and molecular variability of Uromyces appendiculatus (Pers.) Unger, causal agent of bean rust, was studied in a metapopulation from the two major centers of domestication of common bean (Phaseolus vulgaris L.). Specificity of bean rust pathogen isolates was evaluated using a standard set of 19 bean differentials and on bean landrace differentials. Molecular variability was determined from the Random Amplified Polymorphic DNA analysis. The effect of five leaf wetness periods on infection and the incubation period as well as telia production capability of the pathotypes were studied on the susceptible variety Pinto U.I. 114. U. appendiculatus showed broad pathogenic variability throughout the Andean and Middle American regions. Ninety-four virulence patterns (VP)s were identified; most of them were unique to each country and virulence of isolates ranged from 6 to 13 susceptible standard differentials. The most virulent pathotypes were found in Middle America. Cluster analysis grouped isolates into three major VP groups: predominantly Andean, predominantly Middle American, and mixed Andean and Middle American. The Andean pathogen population was more specific to Andean bean landraces while the Middle American was virulent on bean landraces from both geographic regions. Significant differences among five leaf wetness periods were detected. Most of the isolates required 4 to 6 h wetness duration for infection. No infection was observed after a 2 h leaf wetness period. Telia production capability differed between regions with 54% and 37% of isolates from the Andes and Middle America, respectively, producing telia. No correlation was detected between VPs and either wetness requirements or telia production. The RAPD analysis of U. appendiculatus isolates showed high molecular variability. No specific banding patterns differentiated isolates of Andean from isolates of Middle American populations. Cluster analysis of RAPD banding patterns confirmed the three major VP groups. No banding patterns were associated with either geographic origin or telia production capability. Agreement of clusters derived from virulence and those derived from molecular analysis provided evidence for coevolution between U. appendiculatus and its bean host.
Subject Area
Plant pathology
Recommended Citation
Araya Fernandez, Carlos Manuel, "Pathogenic and molecular variability and telia production of Uromyces appendiculatus isolates from the Andean and Middle American centers of domestication of common bean" (1996). ETD collection for University of Nebraska-Lincoln. AAI9715951.
https://digitalcommons.unl.edu/dissertations/AAI9715951