Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/15/2002
Publication Date: 12/1/2003
Citation: Moran, P.J., Cheng, Y., Cassell, J.L., Thompson, G.A. 2003. Gene expression profiling of Arabidopsis thaliana in compatible plant-aphid interactions. Archives of Insect Biochemistry and Physiology. 51:182-203. Interpretive Summary: Insects that use needle-like stylets to suck juices out of plants, such as aphids, cause great economic damage to crops and transmit plant pathogens that cause diseases. Plants defend themselves after infestation by making proteins that increase resistance. In order to work, these proteins depend on genes in the plant. We infested a plant closely related to cabbage, broccoli and Brussels sprouts with green peach aphids or cabbage aphids for 72 or 96 hours. We used glass slides containing thousands of spots of DNA and laser scanning to determine which genes were turned on by aphid feeding. We found that aphids stimulated genes that make signals in the plant warning it of attack. Also, aphids increased the levels of genes involved in plant protection against leaf death, and genes that help defend the plant against pathogens. Aphid feeding clearly led to a unique type of defense in our plants. This defense incorporated the genes that the plant can use against both chewing insects like caterpillars and plant disease. This information provides new ideas for improving resistance to aphids and other insects by genetic modification of crop plants.
Technical Abstract: Phloem feeding involves unique biological interactions between the herbivore and its host plant. The economic importance of aphids as pests has prompted research to define the behavioral foundations of feeding, and to isolate sources of resistance to piercing-sucking insects in crops. Little information exists about the molecular nature of plant sensitivity to phloem feeding. Recent discoveries involving elicitation by plant pathogens and chewing insects and studies on phloem feeders suggest that aphids are capable of inducing responses in plants broadly similar to those associated with pathogen infection and wounding. Our past work showed that compatible aphid feeding on leaves of Arabidopsis thaliana induces localized changes in levels of transcripts of genes that are also associated with infection, mechanical damage, chewing herbivory or resource allocation shifts. However, the response profile as a whole is likely specific to feeding by aphids. We used microarray and macroarray gene expression analyses of infested plants to better define this profile. The results suggest that genes involved in oxidative stress, calcium-dependent signaling, and tryptophan and aromatic compound biosynthesis are part of the dynamic response of A. thaliana plants infested for 72 and 96 hours. The use of plant resistance to aphids in crops will benefit from a better understanding of induced responses. The establishment of links between insect elicitation, plant signaling associated with phloem feeding, and proximal resistance mechanisms is critical to further research progress.