Monday, December 11, 2006

Green peach aphid, Myzus persicae (Sülzer), - Arabidopsis ssi2 mutant interactions

Joe Louis, joelouis@ksu.edu1, Venkatramana Pegadaraju,, Jyoti Shah, shah@ksu.edu2, and John C. Reese, jreese@ksu.edu3. (1) Kansas State University, Graduate Student, Department of Entomology, 123 West Waters Hall, Department of Entomology, Manhattan, KS, (2) Kansas State University, Division of Biology, Ackert Hall, Manhattan, KS, (3) Kansas State University, Department of Entomology, 125 West Waters Hall, Department of Entomology, Manhattan, KS

Aphids are phloem-feeders that feed on a variety of plants causing extensive damage. Green peach aphids (GPA), Myzus persicae (Sülzer) (HEMIPTERA: APHIDIDAE), utilize their incredibly slender stylets to penetrate in between the cells and consume copious amounts of photoassimilates present in the phloem sap. The GPA can also act as the vector for economically important plant viruses. We have developed an Arabidopsis-GPA model, in which we use the combined approaches of genetics, genomics and electrophysiological tools to characterize the response of the GPA on Arabidopsis thaliana. The Arabidopsis ssi2 (suppressor of SA insensitivity2) mutant constitutively accumulate high levels of salicylic acid (SA), which confers resistance against pathogens. No-choice test (antibiosis) indicates that there is a significant reduction in the number of GPAs on the ssi2 mutant as compared to the wild type (WT) plant, whereas, the choice test (antixenosis) shows similar numbers of GPAs on both ssi2 mutants and the WT plants. The Electrical Penetration Graph (EPG) technique has been used to monitor the feeding behavior of GPA on the ssi2 mutant and WT plant. It enables us to quantify the different events of stylet penetration, ingestion, salivation and cell puncturing. The EPG results confirms that there is no significant difference in the total duration of the sieve element phase (SEP) spent by GPA on ssi2 mutant and WT plant. Also, counting the number of GPAs treated with ssi2 mutant phloem sap in artificial diet, will help us to elucidate the role of any toxins/chemicals present in phloem sap which adversely affects GPAs reproduction or feeding.

Species 1: Hemiptera Aphididae Myzus persicae (green peach aphid)