Abstract
The parasitic plant Cuscuta campestris is dependent on its host for water, assimilates and amino acids. It can be controlled by the herbicide glyphosate, which inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), resulting in shikimate accumulation. In this study, C. campestris was parasitic on transgenic tobacco plants expressing green fluorescent protein (GFP) in the phloem. Changes in [14C]sucrose and GFP accumulation in the parasite were used as indicators of the herbicide's effect on translocation between the host and parasite. Host plants were treated with glyphosate 22 days after sowing. Shikimate accumulation in the parasite 1 day after glyphosate treatment (DAGT) confirmed EPSPS inhibition in C. campestris. No damage was visible in the host plants for the first 3 DAGT, while during that same time, a significant reduction in [14C]sucrose and GFP accumulation was observed in the parasite. Thus, we propose that the parallel reduction in GFP and sucrose accumulation in C. campestris is a result of a glyphosate effect on the parasite's ability to withdraw assimilates from the host.
Original language | English |
---|---|
Pages (from-to) | 790-796 |
Number of pages | 7 |
Journal | Planta |
Volume | 219 |
Issue number | 5 |
DOIs | |
State | Published - Sep 2004 |
Bibliographical note
Funding Information:Fig. 7 Shikimate accumulation in C. campestris, and treated host leaf and apex 72 h after glyphosate treatment (five replicates). Means ± SE Acknowledgments This research was supported in part by grant no. TA-MOU-01-CA20-006 from the U.S.–Israel Cooperative Development Research Program, Bureau for Economic Growth, Agriculture, and Trade, U.S. Agency for International Development. The authors are obliged to D.L. Shaner (USDA, AERC, Fort Collins, CO, USA) and S.O. Duke (USDA ARS, NPURU, University, MS, USA) for their critical review of the manuscript.
Keywords
- 5-Enolpyruvylshikimate-3-phosphate synthase
- Cuscuta
- Glyphosate
- Green fluorescent protein
- Sucrose translocation (inhibition)