Strawberry red leaf phytoplasma was found in strawberry plants from production fields in Lules (Tucumán province) and Bella Vista (Corrientes province), Argentina. Characteristic strawberry red leaf symptoms were stunting, young leaves with yellowing at the edges, mature leaves which curled and were reddish at the abaxial face, flower and fruit deformation and death. The pathogen was detected with phytoplasma-universal primer pairs P1/P7 followed by R16F2n/R16R2 as nested primers in 13 diseased plants. Based on RFLP and sequence analysis of the amplified 16S rRNA gene, the phytoplasma was related to the 16SrXIII group (Mexican periwinkle virescence).In silicothe RFLP profile of all the samples analysed revealed the presence of a unique pattern, showing that the novel phytoplasma is different from all the phytoplasmas currently composing the 16SrXIII group. The phylogenetic analysis was consistent with RFLP analysis as the strawberry red leaf phytoplasma was grouped within the 16SrXIII group, but formed a particular cluster. On this basis, the Strawberry red leaf phytoplasma associated with strawberry red leaf disease was assigned to a new subgroup, 16SrXIII-F.

Strawberry plants showing symptoms of lethal redness disease were found in production fields located in Tucumán province, Argentina. The presence of phytoplasmas was confirmed by PCR of 16S rDNA gene using phytoplasma universal primers. According to the 16S rDNA gene sequence identity, the four isolates analysed are related to the X-disease group (16SrIII) (identity ~99 %). These results were confirmed by in silico RFLP, actual RFLP and also by phylogenetic analyses of the 16S rDNA gene. This new phytoplasma was named as Strawberry X-Redness (StrawXR). The results from virtual and actual RFLP analyses of 16S rDNA gene revealed the presence of subgroup 16SrIII-J and three new 16SrIII subgroups. This is the first record of phytoplasmas from X-disease group associated strawberry in Argentina. These results confirm the prevalence of X-disease group and also contribute to the knowledge of diversity of phytoplasmas in this region.

Herein, we report the draft genome sequence of “ Candidatus Phytoplasma pruni” strain ChTDIII (subgroup 16SrIII-B). The final assembly consists of 790,517 nucleotides organized in 67 contigs (minimal size, 1 kb), with a G+C content of 29.4% and encoding 672 proteins.