Journal of Plant Pathology Archive

Abstract:

Saffron (Crocus sativus, Iridaceae), a crop widely grown in Iran, was checked in 2011-2015 for the presence of potyviruses collecting a total of 890 leaf tissue samples. DAS- or ACP-ELISA were performed using a Potyvirus genus-specific and other commercial kits (DSMZ, Germany) against 16 different viruses, including three potyviruses, i.e. bean yellow mosaic virus (BYMV), turnip mosaic virus (TuMV) and soybean mosaic virus (SMV), previously reported from C. sativus (Grilli Caiola and Faoro, 2011). The results showed that 641 samples (> 70%) reacted positively only with Potyvirus genus-specific and bean common mosaic virus (BCMV)-specific antibodies. The coat protein (CP) gene and 3'-terminal sequence of the saffron potyvirus was amplified using generic potyvirus primers PV21/T7 and PV1/SP6 (Mackenzie et al., 1998). The deduced CP sequence shared only 69% amino acid identity to BCMV. The complete 9693 nt genome sequence [excluding poly(A)tail] of isolate Ir-Kh1 was obtained by primer walking and deposited in GenBank (accession No. KY562565). Whole genome nucleotide sequence analysis showed highest identity value of 69% with East Asian passiflora virus (EAPV, KP114137) and 68% with SMV (AJ310200), bean common mosaic necrosis virus (BCMNV, HG792063) and wisteria vein mosaic virus (WVMV, AY656816). Based on the current species demarcation criteria for Potyviridae 2 (Adams et al., 2005), the saffron-infecting virus is a new species in the Potyvirus genus tentatively named saffron latent virus (SaLV), grouping into the BCMV subgroup of the genus. The presence of SaLV was verified in all 70 ELISA-positive samples by RT-PCR using SaLV-specific primer pair For/Rev (5'-ACCATACATTGCAGAGACAGC-3'/ 5'- CGAAAGGTGGTAGAACCACTC-3'), designed on the CP gene. The high prevalence of SaLV may be due to vegetative propagation of saffron, which cannot undergo an effective selection becaue of the latencey of infections.