Morphological and Molecular Characterization of and the Newly Recorded Cyst Nematode, Associated with Chinese Cabbage in Korea.

The sugar beet cyst nematode, is a well known pathogen on Chinese cabbage in the highland fields of Korea. However, a race of cyst forming nematode with close morphological resemblance to was recently isolated from the same Chinese cabbage fields. Morphological species differentiation between the two cyst nematodes is challenging, with only minor differences between them. Thus, this study described the newly intercepted population, and reviewed morphological and molecular characteristics conceivably essential in differentiating the two nematode species. A comparison of morphometric measurements of both infective juveniles and vulval cones of cysts showed significant differences between the two cyst nematodes. When total RNA and genomic DNA were extracted from a mixed field population, I genes and ITS regions were clearly amplified with primers of the two species, suggesting that population collected from the Chinese cabbage field consisted of a mixture of two species. I and ITS of were predominantly amplified from nucleotides prepared from monoxenic population whereas those of were strongly detected in monoxenic cultures. Thus, this study confirms the coexistence of the two species in some Chinese cabbage fields; and the presence of in Korea is reported here for the first time.