Eleonora Satta

Molecular detection and identification of 16SrII group and aster yellows phytoplasmas associated with longan witches’ broom syndrome in Vietnam

Longan witches’ broom syndrome is one of the most devastating epidemic in the majority of longan-growing areas of Vietnam. Main symptoms are small and roll upwards leaves, shortened internodes, and witches’ broom. Diverse etiology is reported for this syndrome enclosing viruses and eriophyoid mites. In this work, using a DNA approach based on 16S rDNA gene, phytoplasmas belonging to 16SrII and 16SrI groups were associated with longan witches’ broom syndrome, corroborating previous findings in Vietnam and in other longan-growing countries of other phytoplasmas associated with the same syndrome.

Interaction between cold atmospheric plasma and phytoplasmas in micropropagated infected periwinkle shoots

Plasma activated water (PAW) was employed to treat phytoplasma infected micropropagated periwinkle shoots to verify effects on symptomatology and phytoplasma presence. The preliminary results indicate that PAW do not induce shoot toxicity, and allow an improved detection of phytoplasma presence in shoots and also in liquid phytoplasma isolation medium. The reduced symptomatology and the lack of colony formation from liquid isolation medium induce to speculate that PAW interact with phytoplasmas and/or endophytes viability. Research to verify these aspects are in progress.

Detection and multigene characterisation of a ‘Candidatus Phytoplasma prunorum’-related phytoplasma associated with witches’ broom symptoms in pineapple fruit

Pineapple samples showing witches’ broom symptoms in the leaves at the top of the fruit were analysed to verify phytoplasma presence. 16SrX group phytoplasmas were detected after nested PCR amplification with specific primers and RFLP analyses. Sequencing of 16Sr DNA allows verification that phytoplasmas from pineapple show a 99% shared identity with ‘Candidatus Phytoplasma prunorum’. Further characterisation of the phytoplasma on ace, imp and secY genes by RFLP analyses on amplicons obtained in nested PCR assays enable the differentiation of the strain infecting pineapple from those detected in fruit trees in Europe and used as reference strains. This is the first report of phytoplasmas belonging to the 16SrX-B group from a species different from pome and stone fruit worldwide.