Phytoplasmas diversity and identification of new aster yellows subgroup (16SrI) associated with weed species in Argentina.

Symptoms of phytoplasma infection were observed in different weed species, , , and , collected from diverse geographical regions in Argentina. To confirm the association of phytoplasma infection with symptomatic plants, PCR, RFLP and phylogenetic analyses based on 16S rRNA-encoding sequences were performed. In this work, we report the presence of phytoplasmas from group 16SrVII (subgroup 16VII-B) infecting and and from group 16SrIII (subgroup 16SrIII-X) , , and . Phytoplasmas from the aster yellows group were detected infecting and . Analysis of 16S rRNA-encoding genes revealed the presence of two distinct operons, (16SrI-B) and newly described , which is different from the reference RFLP patterns of all previously established 16SrI-subgroups. A single operon sequence analysis reveals the presence of simple infection and confirms a description of a novel subgroup. On the basis of these results we propose a designation of new subgroup 16SrI-(B/AJ) AJ (-AJ). To our knowledge, this is the first report of phytoplasmas infecting ¸ and .