The First Report of Globodera rostochiensis Pathotypes Ro5 Occurrence in Poland.

Potato (Solanum tuberosum L. subsp. tuberosum) is one of the most important crops in Poland. During vegetation season, pests and pathogens including a quarantine-significant nematode Globodera rostochiensis (Woll.) Behrens can infect growing plants. Regional surveys have revealed potato cyst nematodes (PCN) to be widely distributed in Poland, with the highest infestation throughout the northwest of the country. Since 1946, only pathotype Ro1 of G. rostochiensis has been recorded. Previous data revealed the occurrence of pathotype Ro5 in three separate provinces. In recent surveys, 22 soil samples from infested fields in northern and western parts of Poland were collected. Each sample comprised 10 kg of soil collected in a grid pattern. Samples of approximately 2 kg were dried for extracting nematodes. The cysts were obtained with an automatic cyst extractor (Mekku Gmbh). A molecular test was performed as a first step to discriminate G. rostochiensis from G. pallida. DNA from 30 cysts per sample was extracted with DNeasy Blood and Tissue KIT (Qiagen). Multiplex PCR analysis with two pairs of primers, GroR-GroF and PaR-PaF (1), was employed. The PCR resulted in a single 315-bp DNA fragment specific for G. rostochiensis. No amplification was shown with primers specific for G. pallida. Bioassays on differential genotypes of potato were carried out to identify the pathotype of G. rostochiensis. Five genotypes of potato: S. vernei hybr. 58.1642/4, S. vernei hybr. 62.33.3, S. vernei hybr. 65.346/19, S. multidissectum hybr. P 55/7, S. kurtzianum hybr. 60.21.19, and two varieties, Desiree and Maris Piper, were inoculated with 22 populations of G. rostochiensis cysts (2). Tests were performed in three replications. Eighteen of the cyst populations were pathotype Ro1 and four were pathotype Ro5. The abundance of cysts in locations where the new pathotype was detected suggests that there is a threat of further spread of G. rostochiensis. Consequently, producers and farmers need to grow resistant potato cultivars to keep nematode population below damaging level. To our knowledge, this is the first report of Globodera rostochiensis Ro5 in Poland. References: (1) A. Fullaondo et al. Nematology 1:157, 1999. (2) J. Kort et. al. Nematologica 23:333, 1977.