|IVANAUSKAS, A - Nature Research Centre|
|VALIUNAS, D - Nature Research Centre|
|JOMANTIENE, R - Nature Research Centre|
|PICCIAU, L - Universita Di Torino|
Submitted to: Zemdirbyste-Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2014
Publication Date: 9/30/2014
Citation: Ivanauskas, A., Valiunas, D., Jomantiene, R., Picciau, L., Davis, R.E. 2014. Possible insect vectors of phytoplasmas affiliated with subgroups 16SrI-B, 16SrI-C, 16SrIII-B and 16SrIII-P in Lithuania. Zemdirbyste-Agriculture. 101:313-320.
Interpretive Summary: Phytoplasmas are small bacteria that lack rigid cell walls and are instead bounded only by a single membrane. These bacteria cause many seriously damaging diseases in hundreds of plant species around the world. Phytoplasmas are spread from plant-to-plant by insects that acquire the phytoplasmas by feeding in the veins of diseased plants, thus acquiring the phytoplasmas. The acquired phytoplasma cells multiply in the body of the insect vector and eventually become incorporated into insect saliva, which is then injected into a plant’s veins. Since the geographical extent of spread of phytoplasmas, the frequency of new infections in individual plants, and the species of plants that become infected by a phytoplasma are all dependent upon the identities and feeding preferences of specific insects, it becomes important to learn the identities of the specific insects that carry and spread different phytoplasmas. In this work, we identified insect species that are carrying phytoplasmas within their bodies, and have identified the different phytoplasmas that each insect species carries. The results revealed several insect species as potential vectors (insects that are capable of spreading phytoplasmas). The findings provide the first stage in determining the identities of insects involved in the spread of specific phytoplasmal diseases and will be of interest to plant pathologists, entomologists, diagnosticians, and quarantine agencies worldwide.
Technical Abstract: Phytoplasma strains affiliated with groups 16SrI, 16SrIII, 16SrV, and 16SrXII have been found in Lithuania, but still little is known about insects that could transmit them. In this study, four phytoplasma strains belonging to phytoplasma subgroups 16SrI-B, 16SrI-C, 16SrIII-B and 16SrIII-P were identified in five known insect species and in one unidentified Aphrodes species occurring in Lithuania. Phytoplasma strains of subgroup 16SrI-C were found in the unidentified Aphrodes species, and in Lepyronia coleoptrata and Philaenus spumarius. Phytoplasma strain belonging to subgroup 16SrIII-P was detected in Aphrodes sp., and a phytoplasma of subgroup 16SrIII-B was found in Anaceratagallia ribauti. Phytoplasma subgroup 16SrI-B strains were found in Aphrodes sp., Aphrophora alni, Cicadella viridis, L. coleoptrata, and P. spumarius. These findings indicate that tested individuals of the above mentioned insect species fed on plants infected with phytoplasmas and that these species could possibly act as vectors or occasional hosts for the diverse phytoplasmas. Results from transmission trials revealed that Euscelis incisus is capable of vectoring subgroup 16SrI-C phytoplasma strains that are found in Lithuania. The data open a new pathway toward understanding the spread of phytoplasmal diseases in the country, and toward eventual design of effective disease management strategies. This work is intended to provide base data for further experiments aimed at determining the identities of insect vectors of phytoplasmas in Lithuania.