The Israeli isolate of Tomato yellow leaf curl geminivirus (TYLCV-Is) is a major tomato pathogen, causing extensive crop losses both in the New and Old World. Surprisingly, however, little is known about the molecular mechanisms of TYLCV-Is interactions with tomato cells. Here, we have identified a TYLCV-Is protein, V2, which acts as a suppressor of RNA silencing and which is unrelated to presently known viral suppressors. Specifically, V2, but not other proteins of TYLCV-Is, inhibited RNA silencing of a reporter transgene, GFP. This inhibition elevated the cellular levels of the GFP transcript and the GFP protein, but it had no apparent effect on the accumulation of GFP-specific short interfering RNAs (siRNAs), suggesting that TYLCV-Is V2 targets a step in the RNA silencing pathway which is subsequent to the Dicer-mediated cleavage of dsRNA. Visualization of the sub-cellular localization of TYLCV-Is V2 in plant protoplasts and tissues showed that this protein is associated with cytoplasmic strands and inclusion bodies in the cortical regions of the cell.
Bibliographical noteFunding Information:
We thank Dr. Sondra Lazarowitz for stimulating discussions, Dr. Yiguo Hong for the kind gift of the TYLCV-China C2 cDNA and Ana Mett and Eddy Blasov for excellent technical assistance. This work was supported by a grant from the U.S.–Israel Binational Agricultural Research and Development Fund (BARD) to YG and VC. In addition, the YG laboratory is supported by a grant from the Israel Science Foundation (ISF), and the VC laboratory is supported by grants from National Institutes of Health (NIH), National Science Foundation (NSF), U.S. Department of Agriculture (USDA), and U.S.–Israel Binational Science Foundation (BSF).
- RNA silencing suppressor
- Sub-cellular localization
- Tomato yellow leaf curl virus