Ribosomal DNA sequence comparisons of Colletotrichum graminicola from turfgrasses and other hosts

The 5.8S ribosomal gene and the flanking internal transcribed spacers (ITS) 1 and 2 from Colletotrichum graminicola isolates causing anthracnose disea se of Agrostis palustris and Poa species were sequenced. Although bootstrap support was not high, two major groups were observed with both UPGMA and p arsimony algorithms, one containing isolates from A. palustris and another with isolates from Poa spp. The ITS sequences were also compared with those of isolates of C. graminicola and C. sublineolum from Sorghum spp., Zea ma ys and Rottboellia cochinchinesis as well as other Colletotrichum species. Except for one isolate from P. annua in Texas, the ITS1 and ITS2 sequences of turfgrass isolates always grouped separately from C. graminicola or C. s ublineolum from non-turfgrass hosts with high bootstrap support. ITS sequen ces of the turfgrass isolates were more similar to those of other species o f Colletotrichum, such as C. coccodes and C. dematium, than they were to C. graminicola isolates from other hosts. Turfgrass isolates have ITS sequenc es which are not identical to those of isolates from Zea mays and Sorghum s pecies demonstrating diversity among fungi conventionally classified as C. graminicola.