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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Crop Germplasm Research » Research » Publications at this Location » Publication #267363
Title: Genetic diversity and pathotype determination of Colletotrichum sublineolum isolates causing anthracnose in sorghum

Author
item Prom, Louis
item PERUMAL, RAMASAMY - Kansas State University
item ERATTAIMUTHU, SARADHA - Kansas State University
item LITTLE, CHRISTOPHER - Kansas State University
item NO, EUN-GYU - Texas A&M University
item Erpelding, John
item ROONEY, WILLIAM - Texas A&M University
item ODVODY, GARY - Texas Agrilife
item MAGILL, CLINT - Texas A&M University

Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2012
Publication Date: 1/31/2012
Citation: Prom, L.K., Perumal, R., Erattaimuthu, S.R., Little, C.R., No, E., Erpelding, J.E., Rooney, W.L., Odvody, G.N., Magill, C.W. 2012. Genetic diversity and pathotype determination of Colletotrichum sublineolum isolates causing anthracnose in sorghum. European Journal of Plant Pathology. 133:671-685.

Interpretive Summary: Anthracnose is one of the most important fungal diseases of sorghum worldwide. In this study, we determine the genetic similarity of 232 isolates of the anthracnose pathogen collected between 2002 and 2004 from Texas, Arkansas, Georgia, and Puerto Rico. The results showed that genetic similarity among the isolates was high ranging from 0.78 to 1.00. Similar isolates were put in groups. From each group, a single isolate was selected and the race of the isolate was determined based on the disease reactions of 14 sorghum lines. Two of the isolates selected did not give consistent results, whereas, 17 new races were established from the remaining 18 isolates. Sorghum lines BTx378 and QL3 were resistant to all isolates and BTx623 and TAM428 were infected by all the selected isolates in both years. Because of the pathogen's ability to change rapidly, common sets of sorghum lines and common ways of naming these different races of the pathogen could help direct planting of appropriate lines and aid in the development of long lasting forms of resistant sorghum.

Technical Abstract: 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, Arkansas, Georgia, and Puerto Rico. Analysis 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 for 20 isolates were determined using 14 sorghum lines previously used in Brazil and the United States and 4 from Sudan. Production of light and inconsistent symptoms on all host differentials over two years of greenhouse testing excluded two isolates from pathotype assignment. Seventeen new pathotypes were established from the remaining 18 isolates. Differentials BTx378 and QL3 were resistant to all isolates and BTx623 and TAM428 were universally susceptible both years. Each of these lines had shown differential responses in prior studies, an indication that the pathogen population has sufficient diversity to adapt rapidly to changes in resistant host lines deployed. Common sets of differentials and a standardized nomenclature could help direct planting of appropriate lines and aid in the development of more durable forms of resistance.