Skip to main content
ARS Home » Research » Publications at this Location » Publication #210725
Title: Identification of viral and phytoplasmal agents responsible for diseases affecting plants of Gaillardia Foug. in Lithuania

Author
item VALIUNAS, D - VILNIUS LITHUANIA
item SAMUITIENE, M - VILNIUS LITHUANIA
item NAVALINSKIENE, M - VILNIUS LITHUANIA
item Davis, Robert

Submitted to: Research Journal of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2007
Publication Date: 6/15/2008
Citation: Valiunas, D., Samuitiene, M., Navalinskiene, M., Davis, R.E. 2008. Identification of viral and phytoplasmal agents responsible for diseases affecting plants of Gaillardia Foug. in Lithuania. Agronomy Journal. 6:109-111.

Interpretive Summary: Economically important ornamental plants worldwide are adversely affected by diseases caused by viruses and phytoplasmas. Phytoplasmas are cell wall-less bacteria that are carried from plant to plant by phloem-feeding insects, mainly leafhoppers. The present work was initiated to expand knowledge concerning the biodiversity of phytoplasmas and viruses infecting herbaceous ornamental plants and to address disease problems arising in botanical gardens and in the floriculture industry in Baltic countries. Using indicator plant inoculations, electron microscopy, and serology, we found that plants of Gaillardia spp. were infected by cucumber mosaic virus. Using molecular methods for detection and identification, we found that a phytoplasma with a widely spread new disease, which we termed gaillardia yellows; the phytoplasma is related to clover phyllody disease phytoplasma known in Europe and North America. These results expand the known biodiversity of viruses and phytoplasmas infecting Gaillardia species and identified a virus and a phytoplasma involved in increasing disease incidence in the Baltic region’s floriculture industry. This report will be of interest to diagnostics laboratories and research scientists monitoring disease incidence and to regional commercial floriculture.

Technical Abstract: Gaillardia plants exhibiting symptoms characteristic of viral and phytoplasmal diseases were collected at botanical gardens and floriculture farms in Lithuania. Cucumber mosaic virus was isolated from diseased plants exhibiting symptoms characterized stunting, color breaking and malformation of flowers. The virus was characterized based on electron microscopy, serology, and reactions of inoculated test-plants. Symptoms of general leaf yellowing and general stunting of plants, and virescence and phyllody of flowers were associated with infection by a phytoplasma. Phytoplasmal 16S rRNA gene sequences were amplified in polymerase chain reactions (PCRs) primed by phytoplasma universal primer pairs P1/P7 and R16F2n/R16R2. RFLP analysis of the 1.2 kbp rDNA product, subjected to single enzyme digestions with nine restriction endonucleases, revealed that the Gaillardia plants were infected by a phytoplasma (gaillardia yellows, GaiY) nbelonging to group 16SrI (aster yellows phytoplasma group), subgroup I–C (clover phyllody, CPh, phytoplasma subgroup). 16S rDNA sequence alignments and phylogenetic analysis confirmed that the GaiY phytoplasma was closely related to CPh phytoplasma. Gaillardia naturally can be infected by broad biodiversity of phytoplasma stains belonging to subgroups 16SrIII–B (clover yellow edge subgroup), 16SrI–A (aster yellows subgroup), and 16SrI–C in Lithuania.