First report of a 'Candidatus Phytoplasma phoenicium'-related strain (16SrIX-I) associated with yellowing of Onobrychis viciifolia in Iran

摘要

Onobrychis viciifolia (common sainfoin) is a forage legume which enhances biodiversity within agro-ecosystems and is an important forage crop in Iran. During 2014-16, O. viciifolia plants were observed with symptoms of yellowing (Fig. 1), little leaf and reddening of leaflet margins (Fig. 2), witches’ broom and dwarfing compared with healthy plants (Fig. 3). The disease, known locally as sainfoin yellowing (SY), was observed in Shalamzar and Shahre Kian locations in Chaharmahal and Bakhtiari province, Iran. In each area, three 1,000 m2 fields were selected randomly and sampled at five points within one square metre on a diagonal transect across each of the fields. The number of diseased plants and the total number of plants in each sampled square metre was determined to calculate the extent of the disease; this being 32% in Shalamzar and 22% in Shahre Kian.