PEPPER LEAF CURL DISEASE CAUSED BY TOMATO YELLOW LEAF CURL SARDINIA VIRUS ON PEPPER IN SOUTHERN ITALY

An outbreak of pepper leaf curl disease (PLCD) was observed in pepper crops under plastic tunnels in the Ionian coast of Basilicata region in summer and autumn 2008. Diseased plants showed stunting, flower abortion, light mosaic, leaf distorsion, marginal leaf chlorosis and upward leaf curling. The disease reached, in some instances, a 50% incidence. Large Bemisia tabaci populations were observed on the crop. Assays for the presence of Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV) were performed to idendtify the etiological agent. About 200 symptomatic samples were collected from different locations and assayed by DASELISA using a combined reagent detecting TYLCV, TYLCSV and other Begomoviruses, 176 of which reacted positively. To discriminate among TYLCSV, TYLCV or other Begomoviruses, 15 ELISA-positive samples were analyzed by PCR using a couple of synthetic oligonucleotides allowing the amplification of the whole coat protein (CP) gene. RFLP analysis of the 1008 bp long PCR product showed the presence of only TYLCSV in all assayed samples. The molecular characterization of the sequenced CP gene revealed that this isolate shares a similarity of 97 % with the corresponding sequence of a tomato TYLCSV isolate from Sicily and is almost identical with the pepper isolate CAB-It recovered in the same area in 2007. The wide and further spreading of PLCD in the monitored area is to be connected with the presence of tomato crops, of weed hosts alternative to pepper, and with the strong presence of the B biotype of B. tabaci.