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United States Department of Agriculture

Agricultural Research Service

Research Project: GENOME SEQUENCE-BASED STRATEGIES FOR DETECTION & IDENTIFICATION OF PLANT PATHOGENIC PHYTOPLASMAS & SPIROPLASMAS, & VASCULAR WALLED BACTERIA

Location: Molecular Plant Pathology

Title: New subgroup 16SrIII-V phytoplasmas associated with false-blossom diseased cranberry (Vaccinium macrocarpon) plants and with known and potential insect vectors in New Jersey

Authors
item Lee, Ing Ming
item Polashock, James
item Bottner, Kristi
item Bagadia, Prachi -
item Rodriguez-Saona, Cesar -
item Zhao, Yan
item Davis, Robert

Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 6, 2014
Publication Date: June 1, 2014
Citation: Lee, I., Polashock, J.J., Bottner-Parker, K.D., Bagadia, P.G., Rodriguez-Saona, C., Zhao, Y., Davis, R.E. 2014. New subgroup 16SrIII-V phytoplasmas associated with false-blossom diseased cranberry (Vaccinium macrocarpon) plants and with known and potential insect vectors in New Jersey. European Journal of Plant Pathology. 139:393-400.

Interpretive Summary: Cranberries are a major commercial crop in several US states. New Jersey cranberry production ranks third after Wisconsin and Massachusetts. Cranberry false-blossom (CBFB) disease had been the major threat to the cranberry industry in the first half of the 20th century but it has been largely controlled through the efforts of scientists from the United States Department of Agriculture in cooperation with New Jersey and Massachusetts State Experimental Stations. However, recently the disease reappeared sporadically in commercial cranberry farms and it may pose potential economic impacts on the steadily growing cranberry industry in New Jersey. Previous electron microscopy studies of diseased cranberry tissue indicated that the disease was associated with a cell wall-less bacteria. Because of a lack of molecular tools for identification of the presumed disease pathogen, it is almost impossible to conduct a large scale investigation of the extent of disease spread. In the present study we examined numerous CBFB infected plants as well as leafhopper vectors from cranberry farms in New Jersey and identified the associated pathogen through employed molecular procedures. Based on molecular analysis of ribosomal gene sequences of the presumed pathogen, we clarified for the first time the pathogen identity and confirmed that a bacterial pathogen (phytoplasma) was directly associated with the disease. This information should facilitate the development of specific molecular probes for detecting the associated phytoplasmas in both cranberry and the vectors, and thus make if feasible to conduct a large-scale survey of dissemination and distribution of the disease and to monitor the influx of potential vectors. This information will aid extension workers and plant diagnostician in the development of an effective control measure for this re-emerging disease and will aid implementation of quarantine regulation.

Technical Abstract: The identity of the presumed phytoplasmal pathogen associated with cranberry false-blossom disease has never been fully clarified. In the present study a molecular-based procedure was employed to determine the identity of the phytoplasma. Tissues of cranberry plants exhibiting cranberry false-blossom symptoms were collected from multiple bogs on each of three randomly selected commercial cranberry farms in New Jersey. Leafhoppers, including the known vector Limotettix vaccinii (Van Duzee) (=Scleroracus vaccinii, Euscellis striatulus) and the sharp-nosed leafhopper Scaphytopius magdalensis (Provancher), a known vector of blueberry stunt disease, were collected from two different farms in New Jersey. Nested PCR assays and RFLP analysis of 16S rRNA gene sequences were employed for the detection and identification of the associated phytoplasmas. All of 20 cranberry plants sampled and five out of 14 batches of leafhoppers tested positive for phytoplasma. Virtual RFLP and sequence analyses revealed that all the associated phytoplasmas were members or variants of a new subgroup, 16SrIII-V. Phylogenetic analysis of 16S rRNA sequences indicated that cranberry false-blossom phytoplasma strains represented a lineage distinct from other 16SrIII subgroups. This is the first report that a new phytoplasma is associated with cranberry false-blossom disease and associated with both leafhopper species in New Jersey.

Last Modified: 8/29/2014
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