A group of plant proteins, expansins, have been identified as wall-loosening factors and as facilitators of cell expansion in vivo. The root knot nematode Meloidogyne javanica establishes a permanent feeding site composed of giant cells surrounded by gall tissue. We used quantitative PCR and in situ localization to demonstrate the induction of a tomato (Lycopersicon esculentum cv. VF36) expansin (LeEXPA5) expression in gall cells adjacent to the nematode feeding cells. To further characterize the biological role of LeEXPA5 we have generated LeEXPA5-antisense transgenic roots. The ability of the nematode to establish a feeding site and complete its life cycle, the average root cell size and the rate of root elongation were determined for the transgenic roots, as well as the level of LeEXPA5 expression in non-infected and nematode-infected roots. Our results demonstrated that a decrease of LeEXPA5 expression reduces the ability of the nematode to complete its life cycle in transgenic roots. We suggest that a plant-originated expansin is necessary for a successful parasitic nematode-plant interaction.
Bibliographical noteFunding Information:
Acknowledgments Tali Z Gal and Elitsur R. Aussenberg contributed equally to this work. This work was supported by an Israeli Science Foundation Grant (number 522/02-1) to HK and YK. We thank Dr. Jim Haseloff (Department of Plant Sciences, University of Cambridge, UK) for donating the pBIN m-gfp5-ER plant transformation vector and Dr. Ruth Markus and Mrs. Miri Zarhi from the Department of Statistics at the Volcani Center for the statistical analysis.
- Cell wall
- Egg mass
- Giant cell
- Root growth