Vernonia brasiliana is a wild species frequently found in Brazilian savanna areas, also known as "cerrado" areas. In pasture fields, shrubs were observed displaying typical symptoms induced by phytoplasmas, which were characterized by shoot proliferation, mild leaf chlorosis and deformed leaves. Molecular detection revealed the presence of phytoplasmas in approximately 80% of the symptomatic plants. Identification by computer-simulated RFLP allowed the classification of phytoplasma strains as representatives of 'Candidatus Phytoplasma pruni', taxonomic subgroups 16SrIII-B and 16SrIII-J. Moreover, phylogenetic analysis evidenced perfect agreement with virtual RFLP. Both phytoplasmas found in diseased vernonia plants have been reported in diverse commercial species cultivated in Brazil, including many vegetables and an extensive number of crops. These findings identify V. brasiliana as a new host of phytoplasmas affiliated with the subgroups 16SrIII-B and 16SrIII-J and suggest this species as a probable reservoir and possible inoculum source of phytoplasmas.

Brachiaria spp. are the most important and widely used warm season grasses for pasture, but are also important weeds for most economic crops in the tropics. During phytoplasma surveys in pasture fields, asymptomatic plants of Brachiaria decumbens were collected for inspection. Nested PCR detected phytoplasmas in more than 90% of sampled plants. Based on computer-simulated RFLP and a similarity coefficient calculation, a subgroup 16SrIII-J phytoplasma was molecularly characterized. Phylogenetic analysis was consistent with virtual RFLP identification. Representatives of this subgroup have been identified in diverse Brazilian regions encompassing various commercial crops. Our study revealed B. decumbens as a new host and reservoir of 16SrIII-J phytoplasma. Keywords Diseases of grasses. Mollicutes. Pasture grasses. Yellows diseases Phytoplasmas are wall-less bacteria inhabiting phloem vessels that are associated with numerous diseases widely distributed globally. These bacteria are disseminated by sap-sucking insect vectors and are currently classified in groups and subgroups based on the genetic variability of the 16S rRNA gene (Lee et al. 2000).

Vernonia brasiliana is a wild perennial shrub frequently found in pasture areas. Plants of this species have been observed displaying typical symptoms induced by phytoplasmas, which were characterized by shoot proliferation, deformed leaves and leaf chlorosis. The present study confirmed the presence of phytoplasmas in association with affected plants. Sequencing of the 16S rRNA gene, computer-simulated RFLP analysis and phylogenetic analysis revealed that one of the phytoplasmas identified was representative of novel subgroup. The sequence identity scores between the novel strain and those of previously described 'CandidatusPhytoplasma fraxini'-related strains was 99 %, while similarity coefficient values were lower than 0.97. These findings provide support to delineate the phytoplasma found in vernonia plants as a reference phytoplasma for a novel subgroup designated 16SrVII-F. This representative of the novel subgroup was denominated VbSP phytoplasma (Vernonia brasiliana Shoot Proliferation; GenBank KX342018). The results of the present study revealed V. brasiliana to be a host of phytoplasmas, evidenced a novel phytoplasma associated with phytoplasmal disease in Brazil and extended the knowledge of the genetic diversity existing within the 16SrVII group.

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