Abstract
The study was undertaken to observe the phytoplasma incidence in carrot (Daucus carota), cabbage (Brassica oleracea var.
capitata) and onion (Allium cepa) plants during 2017 in Punjab, Pakistan. Phytoplasma induced symptoms such as yellowness,
proliferation, phyllody and stunted growth were observed on studied plants. Moreover, pleomorphic phytoplasma bodies were
seen in phloem cells of infected plant samples using electron microscopy. The presence of phytoplasma in infected plant
samples was further confirmed by nested PCR amplification of 16SrDNA using universal primer pairs (P1/P7 and RI6F2n/R2).
Amplicons of 1.8 Kbp and 1.2 Kbp were obtained in PCR, visualized on 1.5 % agarose gel electrophoresis. Restriction
Fragment Length Polymorphism (RFLP) profiles and Sequencing proved that pattern of studied vegetables isolates is same
with Sesamum phyllody reference strain of 16SrII-D subgroup. The phylogenetic analysis confirmed the 99-100% sequence
homology to Peanut witches-broom phytoplasma strain of 16SrII-D subgroup. Various insect species were collected from
vegetable fields of three above mentioned crops. Among those, Empoasca spp. O. albicinctus, A. bigutula and Nervosa spp.
were resulted phytoplasma positive while some other species of unknown leafhoppers and aphids were negative. The PCR
positive insect vectors could be involved in transmission of phytoplasma in vegetables. This is the first report of vegetable
association with phytoplasma and their potential insect vectors.
