Genetic diversity and pathotype determination of Colletotrichum sublineolum isolates causing anthracnose in sorghum

Prom, L.K. and Perumal, R. and Erattaimuthu, S.R. and Little, C.R. and et al, . (2012) Genetic diversity and pathotype determination of Colletotrichum sublineolum isolates causing anthracnose in sorghum. European Journal of Plant Pathology, 133 (3). pp. 671-685.

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Amplified fragment length polymorphism (AFLP) based genetic diversity was analyzed for 232 Colletotrichum sublineolum isolates collected between 2002 and 2004 from three geographically distinct regions of Texas, and from Arkansas, Georgia, and Puerto Rico. Results revealed significant levels of polymorphism (59%) among the isolates. Even so, genetic similarity between isolates was high, ranging from 0.78 to 1.00. Clustering of similar isolates did not correlate with either geographic origin or year of collection. Pathotypes of 20 of the isolates were determined using 14 sorghum lines previously used in Brazil and the United States and 4 from Sudan. Seventeen new pathotypes were established from the 18 isolates that gave uniform and consistent reactions on all host differentials over 2 years of greenhouse testing. Differentials BTx378 and QL3 were resistant to all isolates while BTx623 and TAM428 were universally susceptible both years. Each of these lines had shown differential responses in prior studies indicating that the pathogen population has sufficient diversity to adapt rapidly to changes in resistant host lines deployed. When the 2-step pathotype classification scheme was used, the 18 isolates examined in this study were placed in four pathotype groups (A, C, D and G), which would further then be separated into ten distinct pathotypes. Common sets of differentials and a standardized nomenclature will allow for comparison to be made among pathotypes of C. sublineolum detected from different regions and also could help direct planting of appropriate sorghum lines and aid in the development of more durable forms of resistance.

Item Type: Article
Uncontrolled Keywords: AFLP. Fungal plant pathogen . Host differentials
Author Affiliation: USDA-ARS, Southern Plains Agricultural Research Center, College Station, TX, USA
Subjects: Crop Improvement
Divisions: Sorghum
Depositing User: Mr B Krishnamurthy
Date Deposited: 25 May 2013 12:49
Last Modified: 25 May 2013 12:49
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