The Potato Aphid Effector Me10 Targets Plant Defense to Enhance its Performance
Authors:Ritu Chaudhary, Jennifer Goodrich
Mentor:Isgouhi Kaloshian, Professor of Nematology, University of California, Riverside
Aphids are important agricultural pests. During feeding on host plants, aphids secret copious amount of saliva. Aphid saliva contains large number of proteins which are delivered into plant cells and modulate plant defense responses. The proteins in the potato aphid (Macrosiphum euphorbiae) saliva were identified using mass spectrometry (MS). Among these, was a protein encoded by the gene Me10. Expressing Me10 in planta enhances aphid reproduction compared to control plants. Sequence analysis indicated that this gene is uncharacterized, has no known function, and homologous sequences exist only in aphid species. To determine the function of Me10, a yeast two-hybrid screen was performed to identify tomato proteins interacting with Me10. Me10 was used as a bait to screen a tomato cDNA library prepared from healthy leaves and leaves fed on by aphids. About six million cDNA clones were screened and 58 interacting clones were identified. Restriction digestion analysis indicated that only 33 were distinct clones. The cDNA containing plasmids were isolated from these clones and tested again for interaction with Me10. Seventeen clones were found to be true interactors. All 17 clones were sequenced and sequence information showed that the large majority of these clones represented the TFT-7 gene. TFT7 gene encodes a 14-3-3 protein which is known to be involved in plant immunity. Our results indicate that aphid salivary protein Me10 directly targets a plant defense component likely to suppress plant immune responses.