18S rRNA and COI haplotype diversity of Trichodorus obtusus from turfgrass in South Carolina

The stubby-root nematode, Trichodorus obtusus , was recently identified on zoysiagrass in South Carolina, USA. In Florida, T. obtusus causes more damage than other stubby-root nematodes encountered in turfgrass. The objective of this study was to use morphological analysis, mitochondrial DNA (COI: cytochrome oxidase 1) and nuclear (18S rRNA) sequence data to study the genetic structure and haplotype diversity of populations recovered from turfgrasses in South Carolina. Numerous morphological differences were observed among populations. Three 18S haplotypes were shared among South Carolina and Florida populations, and six mitochondrial haplotypes were identified in South Carolina samples. Of the six COI haplotypes, four haplotypes were restricted to one population from St Augustinegrass. The lowest haplotype diversity was found in samples from zoysiagrass. Sequences of the COI mtDNA gene of T. obtusus were published in GenBank and represent the first mtDNA sequences for the genus Trichodorus .