China tree yellows phytoplasma (ChTY) is associated with yellowing disease of China tree (Melia azedarach) in Argentina. According to partial 16S rRNA gene analysis, ChTY phytoplasma belongs to 16Sr XIII group, subgroup G. ChTY strains have 98-99% 16S rDNA gene sequence similarity with 16SrXIII-group phytoplasmas, and less than 97.5% when compared to all 'Candidatus Phytoplasma' described so far, except for the novel "Candidatus Phytoplasma hispanicum". However, ChTY strains are differentiated from the latter by additional molecular and biological attributes. The presence of unique features in 16S rDNA sequence distinguishes ChTY from all currently described 'Candidatus Phytoplasma' species. In silico RFLP profile of 16S rDNA (1.2kb) and rpLV-rpsC (1.3kb) genes distinguished ChTY in 16SrXIII-G subgroup within 16SrXIIII group. The phylogenetic analyses based on 16S rDNA, rpLV-rpsC and secA gene sequences, in addition to the restricted host range, characteristic symptoms and geographical distribution, confirm that the ChTY collective strains represent a distinct lineage within the phytoplasma clade and support the description of the novel 'Candidatus Phytoplasma meliae' species with reference strain ChTY-Mo3 (Montecarlo, Argentina).

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.