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Molecular mechanisms mediating plant-aphid interactions

Aphids are one of the main pests of many crops worldwide. These specialized insects cause important economic loses and their management has negative effects on the environment. In Iowa, one of the main pests of soybean is the soybean aphid, which was accidentally introduced in the US in the year 2000. While some important work had been done regarding the biology and ecology of the insect, the soybean-insect interaction had not been analyzed at the molecular level before we started with this project.

We are specifically interested in understanding the soybean defense mechanisms that are effective against these insects, and the adaptive strategies utilized by the soybean aphid (Aphis glycines) to successfully colonize soybean. We have characterized the effects of aphid feeding on soybean’s transcriptome and metabolome. We demonstrated that soybean utilizes chemical and physical defenses against the insect, and determined the phytohormone signals that regulate this response. We also identified a counter-defense mechanism triggered by aphids that take advantage of phytohormone antagonisms and results in suppression of plant defenses in compatible interactions. Some of these counter-defense mechanisms seem to be triggered during other plant-insect interactions, suggesting that they could be targeted as general strategies of aphid control.

Initial work in this area derived from the collaboration with Dr. Tylka (Plant Pathology, ISU) and Dr. O’Neal (Entomology, ISU). A significant collaboration with Dr Lee (Chemistry, ISU) resulted in the development of a novel MS-imaging technique applicable to soybean leaves.

Accumulation of isoflavones in response to soybean aphid feeding

Mass spectrometry imaging of isoflavone accumulation in soybean leaves in response to aphid feeding.

Figure from Hohenstein et al (2019) Front. Plant Sci. 10:310