Distribution, DNA barcoding and genetic diversity of potato cyst nematodes in Indonesia

Global trading of plant materials, in combination with agricultural practices, may facilitate the spreading of cyst nematodes to so far non-infected areas. Recently Potato Cyst Nematode (PCN) was recognized to be present in Indonesia and both diversity and distribution require further study. Assessment of PCN populations was done by collecting soil samples, determination of morphological characteristics in combination with ITS rDNA and COI mtDNA sequencing. Thirty-seven soil samples were collected from potato fields in the Indonesia archipelago. The results showed the presence of Globodera rostochiensis in 22 out of 37 sampling fields, namely North Sumatra (6 fields), Central Java (12 fields), East Java (3 fields), and -for the first time- in Sulawesi (North Sulawesi) (1 field). The highest observed density was found in Banjarnegara (Central Java), i.e., 872 cysts 100 ml soil−1. Globodera pallida was not recovered. Both ITS and COI characterisation of Indonesian PCN (G. rostochiensis) revealed the virtual absence of sequence variation as compared to most PCN from the rest of the world; the COI sequences were identical to the most common and mostly distributed haplotype around the world. Microsatellite genotyping indicated a higher genetic diversity for populations from East Java than for populations from North Sumatra, suggesting that cysts at the origin of populations in North Sumatra were coming from populations in East Java. These data on species identification, population density, genetic diversity, and distribution of potato cyst nematode over the Indonesian archipelago constitute the very basis for the design of environmentally-sound and effective PCN control strategies.