Natural phytoplasma infections on fruit, vegetable and weed plants at the same agroecosystem and their molecular properties

Abstract

The phytoplasma associated diseases are an emerging threat to fruit and vegetable crops leading severe yield losses worldwide. Pear (Pyrus communis L.) trees, with symptoms of severe reddening, dwarfing and shoot proliferation were observed in pear orchards of Malatya province of Turkey. Tomato (Solanum lycopersicum L.) plants grown nearby the symptomatic pear orchard displaying leaf rolling, severe flower sterility and purple leaves were observed at the same agroecosystem. To verify the presence and diversity of phytoplasmas, symptomatic pears and tomatoes were sampled and weeds nearby the symptomatic plants were collected. Total plant DNA was purified from midrib of collected leaves using a commercial kit. The DNA samples were analyzed by nested polymerase chain reaction (PCR) using universal primer pairs to amplify 16S rDNA fragments. The phytoplasmas detected in collected samples were differed according to the host. Here we detected and characterized ‘Candidatus Phytoplasma pyri’ belonging to apple proliferation group (subgroup 16SrX-C) from a pear tree, ‘Candidatus Phytoplasma trifolii’ belonging to clover proliferation group (subgroup 16SrVI-A) from a weed (Amaranthus retroflexus) and ‘Candidatus Phytoplasma solani’ belonging to the stolbur phytoplasma group (subgroup 16SrXII-A) from a tomato plant. Direct sequencing of PCR products verified the phytoplasmal nature of the infections. The occurrence of ‘Ca. P. trifolii’ on A. retroflexus is the first report for the world. The irregular presence of the phytoplasmas in fruit and vegetable crops and weeds indicates continuous spread of the phytoplasmas threatening the new crops and new horizons.