Submitted to: Entomological Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2007
Publication Date: 12/9/2007
Citation: Quisenberry, S., Ni, X. 2007. Resistant and susceptible responses of cereal hosts to aphid feeding [abstract]. Entomological Society of America Annual Meeting, December 9-12, 2007, San Diego, California.
Interpretive Summary: not required
Technical Abstract: Although cereal host resistance to aphids has been examined extensively, little information is available on etiology of aphid injury and biochemical responses of resistant and susceptible cereal hosts to aphid feeding. Our team examined both aphid and plant factors for the Russian wheat aphid (RWA)-elicited chlorosis formation. The results suggested that chlorophyll loss in wheat seedlings is a Mg-dechelatase-driven process that interrupts normal chlorophyll biosynthesis process by removing Mg from chlorophyll precursor (chlorophyllide a), and degrading it into pheophorbide a. In addition, the responses of RWA-resistant and susceptible wheat, barley, and oat plants to RWA and bird cherry-oat aphid (BCOA) feeding were different. Both oxidation and detoxification responses of cereal hosts to the two aphid species were examined. While the BCOA feeding showed no effect on either oxidation or detoxification enzyme activities in the four cereal genotypes examined, plant responses to the RWA feeding varied. The RWA-feeding elicited the increases of peroxidase activity in the RWA-resistant ‘Halt’ wheat and -susceptible ‘Morex’ barley, but no effect in the RWA-susceptible ‘Arapahoe’ wheat and –resistant ‘Border‘ oat. In addition, the detoxification enzyme assays showed that the RWA feeding caused increase in esterase and superoxide dismutase activities, while the BCOA showed no effect on either esterase or superoxide dismutase activity. The ramification of basic research on insect susceptibility (e.g., chlorosis formation) in integrated pest management will also be discussed.