Phytoplasmas are obligate bacterial pathogens transmitted by phloem-feeding insects and responsible for severe diseases in numerous crops worldwide. In Iran, insect-associated phytoplasma transmission pathways remain poorly resolved, particularly at fine phylogenetic and vector-specific scales. Here, we investigated phytoplasma strains detected in four plant species, grapevine (Vitis vinifera), soybean (Glycine max), barberry (Berberis vulgaris), and the weed Conyza canadensis, and in three potential insect vectors (Tropidocephala prasina, Eysarcoris ventralis, and Nysius graminicola) collected from distinct agroecosystems across Iran. Phytoplasmas were characterized by using nearly full-length 16S rRNA gene sequences and a multilocus dataset of protein-coding genes obtained through a targeted next-generation sequencing approach. Five phytoplasma strains belonging to ribosomal groups 16SrI, 16SrVI, 16SrIX, and 16SrXII were identified, including two novel ribosomal subgroups, 16SrI-AS and 16SrIX-K. Several previously unreported plant–phytoplasma and insect–phytoplasma associations were documented. Comparative phylogenetic analyses revealed that ribosomal and multilocus markers capture complementary evolutionary signals, with protein-coding genes providing additional resolution beyond 16S-based classification. These findings highlight the potential role of diverse hosts and polyphagous insects, not yet confirmed as vectors, in phytoplasma circulation and underscore how high-throughput next-generation sequencing and multilocus approaches advance our understanding of phytoplasma diversity and evolution.
Trivellone et al. (Sat,) studied this question.