title: Expanding and exploring the diversity of phytoplasmas from lucerne (Medicago sativa).
abstract: Phytoplasmas are a group of insect-vectored bacteria responsible for disease in many plant species worldwide. Among the crop species affected is the economically valuable forage species lucerne. Here we provide comprehensive molecular evidence for infection in multiple lucerne plants by a phytoplasma not previously known from this plant species. This phytoplasma had a >99% genetic similarity to an unclassified 16S rRNA subgroup previously reported as Stylosanthes little leaf from Stylosanthes spp. and was genetically and symptomatically distinct from a co-occurring but less common 16SrIIA group phytoplasma. Neighbour-joining analyses with publicly available sequence data confirmed the presence of two distinct phytoplasma lineages in the plant population. No PCR detections were made among 38 individuals of 12 co-occurring weed species. Sequence analysis revealed that all nine PCR detections from among 106 individuals of five Hemiptera insect species from the site, three of which had previously been reported as likely vectors, were false positives. This study demonstrates the importance of sequencing to complement PCR detection and avoid potentially inaccurate conclusions regarding vectors, highlights that sampling over a wide spatio-temporal scale is important for vector and alternative host studies, and extends to eight the number of phytoplasma 16 Sr groups known from lucerne.
authors.affiliation: Graham Centre for Agricultural Innovation (Charles Sturt University &NSW Department of Primary Industries), NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Pine Gully Rd, Wagga Wagga, NSW 2650, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Gopurenko
authors.affiliation: Graham Centre for Agricultural Innovation (Charles Sturt University &NSW Department of Primary Industries), PO Box 883, Orange, NSW 2800, Australia.
authors.forename: Murray J
authors.initials: MJ
authors.lastname: Fletcher
authors.affiliation: Graham Centre for Agricultural Innovation (Charles Sturt University &NSW Department of Primary Industries), PO Box 883, Orange, NSW 2800, Australia.|State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|Institute of Applied Ecology, Fujian Agriculture &Forestry University, Fuzhou 350002, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Graham Centre for Agricultural Innovation (Charles Sturt University &NSW Department of Primary Industries), PO Box 883, Orange, NSW 2800, Australia.|State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|Institute of Applied Ecology, Fujian Agriculture &Forestry University, Fuzhou 350002, China.
authors.forename: Geoff M
authors.initials: GM
authors.lastname: Gurr
mesh_terms: D004269:DNA, Bacterial / Q000235:genetics; D000455:Medicago sativa / Q000382:microbiology*; D010802:Phylogeny; D045582:Phytoplasma / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S