تنوع ژنتیکی، میزبانی و جغرافیایی ویروس‌های برگ ‌قاشقی ‌باقلا، زردی بافت مرده باقلا و کوتولگی بافت مرده باقلا در ایران

Viral diseases of legumes charaterized by yellowing, stunting and leaf rolling cause heavy losses to legume crops. The causal agents of these diseases are Bean leaf roll virus (BLRV) of the genus Luteovirus; family Luteoviridae, Faba bean necrotic yellow virus (FBNYV) and Faba bean necrotic stunt virus (FBNSV) both from the genus Nanovirus, family Nanoviridae, which are widespread in legume species throughout Iran. These viruses are transmitted by aphids in a persistent manner. In the present research, genetic variation, host range and geographical diversity of BLRV, FBNYV and FBNSV isolates were investigated. Samples of Vicia faba, Pisum sativum, Cicer arietinum, Medicago sativa, Lens culinaris, Trifolium spp., Portulaca spp, Glycyrrhiza glabra,Trigonella foenum-graecum and Phaseolus vulgaris showing symptoms of yellowing, dwarfing and leaf rolling were collected from the fields of Markazi, Fars, Hamedan, Kerman, Lorestan, Khuzestan, Kohgiluye-va-Boyerahmad, Golestan, Mazandaran, Chaharmahal-va-Bakhtiyari, Zanjan and Qazvin provinces in 2015-2017. Total nucleic acid was extracted from symptomatic samples and subjected to RT-PCR using BLRV specific primers amplifying fragments of approximately 389, 390 and 560 bp in size from the CP, read through (RTD) and noncoading region of BLRV. The amplified fragments were cloned and sequenced. PCR using specific primers amplifying fragments of approximately 520 and 990 bp in size from the CP and MP regions of the FBNYV and 1000 and 980 bp in size from the Rep and MP regions of the FBNSV was carried out and the amplified fragments were sequenced. Comparison of obtained nucleotide (nt) and amino acid (aa) sequences of Iranian isolates of BLRV, FBNYV and FBNSV with corresponding nt and aa sequences of other isolates available in GenBank showed 98-100% aa and 97.71-100% nt sequence similarity in BLRV CP, 88-99% aa and 87-95% nt sequence similarity in RTD of BLRV, 68.8-84.66% nt sequence similarity in noncoading region of BLRV and 92.31-97.04% aa and 85.33-95.66% nt sequence similarity in DNA-S fragment of FBNYV, 88.6-100% aa and 83.58-99.09% nt sequence similarity in DNA-M fragment of FBNYV and 95-100% aa and 94.32-100% nt in DNA-R fragment of FBNSV, 83.93-100% aa and 76.79-99.69% nt sequence similarity in DNA-M fragment of FBNSV, respectively. Phylogenetic analyses indicated that all Iranian BLRV, FBNYV and FBNSV isolates constituted a group district from the group formed by non-Iranian BLRV, FBNYV and FBNSV isolates.