Alternative weed hosts harbors 16SrII group phytoplasmas associated with little leaf and witches’ broom diseases of various crops in India

The disease symptoms characterised by little leaf, phyllody, stunting and branch proliferation were observed during a field survey conducted from June 2015 to January 2016 on common invasive weeds Cleome viscosa (tick weed), Trichodesma zeylanicum (cattle bush) and Tephrosia perpurea (wild indigo), which were found infected with peanut witches’ broom phytoplasmas (16SrII group) strains. Phylogenetically similar phytoplasma strains were also detected in symptomatic samples of Sesamum indicum (sesame), Vigna unguiculata (cow pea), Phaseolus vulgaris (French bean), Dendrocalamus strictus (bamboo) and Carica papaya (papaya) from the same or adjacent fields. This is the first report of 16SrII-D group phytoplasmas (‘Candidatus Phytoplasma aurantifolia’-related strains) associated with witches’ broom disease of C. viscosa, D. strictus and yellow stunting disease of C. papaya. The association of 16SrII-C group phytoplasmas with witches’ broom disease of T. zeylanicum and T. purpurea is also reported for the first time. From the obtained results, it can be inferred that the weed hosts harbors 16SrII group phytoplasma strains associated with little leaf and witches’ broom diseases of economically important grain legume crop species like S. indicum, V. unguiculata and P. vulgaris.