2012 Annual Report
The majority of research efforts focused on propagating PCN (G. pallida) field populations due to limited numbers of nematode cysts received from Idaho. ARS researchers have bulked up nematode cysts from three field populations and cloned the chorismate mutase (CM) gene from these nematode populations. Sequence analysis revealed that these three field populations contained one predominant GpCM sequence/allele, however, additional sequences/alleles were also identified. Results suggested that genetic variations exist among Idaho field populations. The plan is to clone the GpCM gene from other field populations to have a better understanding of the genetic diversity of G. pallida from Idaho. ARS researchers also cloned the CLE1 parasitism gene from G. pallida. Sequence analysis revealed that both CLE1 and CM genes are relatively conserved between the two PCN (G. rostochiensis and G. pallida) species. RNAi constructs were made targeting the conserved regions of these genes and transformed them into potato. Several transgenic potato lines expressing each of the RNAi construct were obtained. qRT-PCR assays confirmed the expression of dsRNA in the obtained transgenic potato lines. These transgenic potato lines will be tested for infection of both PCN species.