Poster Session: Diseases of Plants - Disease Detection and Diagnosis
492-P
Characterization of Ophiosphaerella species causing spring dead spot disease of bermudagrass in South Carolina and Buenos Aires, Argentina.
A. CANEGALLO (1), S. B. Martin (1), W. J. Park (1), P. Agudelo (2), L. McCarty (2), J. Kerrigan (2), L. Tredway (3), R. Cantoro (4)
(1) Pee Dee Research & Education Ctr, Florence, SC, U.S.A.; (2) Clemson University, Clemson, SC, U.S.A.; (3) Syngenta Lawn and Garden, Zebulon, NC, U.S.A.; (4) Universidad Catolica Argentina, Buenos Aires, Argentina
Spring dead spot (SDS) disease is an important root disease of bermudagrass (Cynodon spp.)in the transition zone habitats around the world. Causal agents have been identified in the U.S. as Ophiosphaerella korrae (OK), O. herpotricha (OH), and O. narmari, but not in Argentina. Pure cultures were obtained from symptomatic roots from six different bermudagrass cultivars from 24 different golf courses in SC, and 21 different golf courses, polo fields and sod farms in Argentina. The ITS region of genomic ribosomal DNA extracted from mycelial tissue was amplified using the primers specific for OK: OKITS1 and OKITS2 and OH: OHITS1 and OHITS2, to identify the causal agents of SDS of bermudagrass in South Carolina and Argentina. In SC, OKITS primers amplified a 454-bp fragment from 207 cultures out of 216 while in Argentina OHITS primers amplified a 454-bp fragment on all of 145 cultures. PCR products were purified and fragments sequenced for phylogenetic analysis among locations within SC and Argentina. This comparative study of the nucleotide sequences of the ITS region does not show significant differences within a geographical region. But, there were significant genetic differences corresponding to location when isolates of OH and OK from Oklahoma and Missouri were compared with the Argentine (OH) and SC (OK) isolates. Also there was no evidence of correlations between Ophiosphaerella spp. with cultivars.