عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The Iranian isolate of tomato leaf curl virus (TLCV-Ir; GenBank Acc. No. AY297924) is a whitefly (Bemisia tabaci) transmitted begomovirus causing leaf curl disease of tomato in Iranshahr (Sistan and Baloochestan province, Iran). To test the infectivity of a full-length 2763 nucleotide DNA of this virus, a partial dimer (head-to-tail) was constructed in the binary vector pBin19 and transferred into Agrobacterium tumefaciens strain C58. A range of potential hosts including Lycopersicon esculentum, Nicotiana tabacum, N. benthamiana, Datura stramonium and some other indicator plants were agroinoculated with a bacterial culture of this construct. Mild curling and yellowing symptoms were observed on newly developed leaves of tomato plants within 30 to 45 days post-inoculation (dpi). However, the next phase of symptom development on tomato occurred 2-3 months after inoculation and produced elongated spindly shoots, smaller leaves and severe leaf cupping on the newly developed leaves. N. benthamiana plants agroinoculated with TLCV-Ir alsoshowed severe symptoms including leaf curling and leaf cupping within 21 to 30 dpi. No symptoms were observed on other agroinoculated plants but dot blot and PCR analysis using TLCV-Ir-specific probes and primers, respectively, confirmed the presence of viral DNA in Datura stramonium and N. tabacum plants indicating that these plants are symptomless hosts of the TLCV-Ir. On the basis of host range, symptom severity, timing of symptom appearance and the level of replication of the virus in host plants in comparison with a severe isolate of TLCV, i.e., the Australian isolate of TLCV, TLCV-Ir is considered as a mild isolate. Transmission of TLCV-Ir from agro-infected tomato plants to healthy tomato seedling was achieved with one adult of B. tabaci and the inoculated plants showed typical symptoms of the disease. The infectious clone of TLCV-Ir can be used as a source of this virus in various studies including screening of resistance cultivars.