Characterization of 16SrII group phytoplasmas associated with alfalfa (Medicago sativa) witches’ broom disease in diverse areas of Iran

Abstract

Alfalfa witches' broom (AWB) is one of the most important alfalfa diseases in Iran. To characterize 16SrII group phytoplasmas associated with this disease, symptomatic and asymptomatic plants were collected during 2013-2015 and subjected to direct and nested polymerase chain reaction (PCR) using P1/P7, R16mF2/R16mR2 and R16F2n/R16R2. PCR amplicons of ~1.8, ~1.4 and ~1.25 kb respectively, were obtained only from all symptomatic plants. Restriction fragment length polymorphism (RFLP) analysis of R16F2n/R2 amplicons showed that the phytoplasma associated with AWB disease were members of 16SrII group subgroups 16SrII-D and-C. Blast analysis of these amplicon sequences and sequence homology of collected strains and strain sequences retrived from GenBank (AWB strains Chahgeer, Juyom and Bushehr) confirmed that AWB phytoplasmas collected from Bafg, Ardakan, Bahabad and Herat (Yazd province), Nikshahr (Sistan-Baluchestan), Bam, Zarand, Jiroft (Kerman province), Bushehr (Bushehr province), Tabas (South Khorasan province), Jowkar (Hamedan province) and Zardenjan (Esfahan province) cluster with phytoplasma strains enclosed in the 16SrII-D subgroup, while AWB strains from Chahgeer (Yazd province) and Juyom (Fars province) cluster with phytoplasma strains in the 16SrII-C subgroup. Based on these results the predominant strains of 16SrII phytoplasmas associated with AWB disease in Iran were classified in the 16SrII-D subgroup. In Ashkezar and Abarkouh in Yazd province entire alfalfa farm was infected with witches' broom disease. In 3 year alfalfa stands in Ashkezar alfalfa farms were plowed due to high incidence of the disease.

Multilocus sequence analysis of phytoplasma strains of 16SrII group in Iran and their comparison with related strains

“…However, detailed studies have shown that WBDL‐Ir phytoplasma (“ Ca . P. aurantifolia,” 16SrII‐B) and AlfWB‐Y phytoplasma (16SrII‐C) have different natural and experimental host ranges and are vectored by different insects (Esmailzadeh Hosseini, Khodakaramian, Salehi, & Bertaccini, ; Salehi, Izadpanah, & Ebrahim Nesbat, ; Salehi, Izadpanah, Siampour, Bagheri, & Faghihi, ). Phylogenetic analysis of this study also identified WBDL phytoplasma on a sub‐lineage distinct from phytoplasmas of 16SrII‐C.…”

Peach witches’-broom, an emerging disease associated with ‘Candidatus Phytoplasma phoenicium’ and ‘Candidatus Phytoplasma aurantifolia’ in Iran

“…widespread and economically important disease (Esmailzadeh Hosseini et al, 2016), transmitted by the leafhopper Orosious albicinctus (Salehi et al, 1995). Thus, alfalfa and O. albicinctus could be involved in the transmission of 'Ca.…”

The association of 16SrVI and 16SrI phytoplasma groups with carrot seeds and weeds in Ankara and Konya provinces in Turkey

“…The phytoplasmas found in weeds around the world mostly belong to the 16SrI, 16SrII, 16SrXI, 16SrXII, and 16SrXIV groups, but some members of the 16SrIII, 16SrIV, 16SrV, 16SrVI, 16SrVII, 16SrIX, 16SrX, and 16SrXXIX groups have also been identified (Duduk et al 2018). Also, studies have shown that while A. retroflexus weed is infested with the 16SrI group, and 16SrV-B and 16SrXII-A subgroups (Credi et al 2006, Wu et al 2010, Yang et al 2011 (Credi et al 2006, Esmailzadeh Hosseini et al 2016a, 2016b. Infections by 16SrIX-C 'withes`s broom' , 16SrI-(B/AJ), and 16SrXII-A phytoplasma subgroups have been reported in wild plants S. arvensis, C. maculatum, and D. carota wild, respectively (Casati et al 2016, Fernández et al 2020, Sertkaya 2014.…”