Expression of the Tomato Leaf Curl Geminivirus C4 Gene Produces Viruslike Symptoms in Transgenic Plants

Transgenic tobacco and tomato plants expressing the C4 gene from tomato leaf curl geminivirus (TLCV), under the control of the cauliflower mosaic virus 35S promoter, developed virus-disease-like phenotypes. Plants transformed with a frame-shift version of the C4 gene construct appeared normal but produced levels of transcript similar to those of plants expressing the C4 gene. Thus, the abnormal plant phenotypes result from translation of the C4 gene. These results support the hypothesis that the C4 open reading frame of TLCV encodes a protein involved in the development of disease symptoms during viral infection.