Characterization of Rag5-Mediated Resistance in Soybean to Soybean Aphid
Abstract
Soybean aphid (Aphis glycines) is an economically important pest of soybean (Glycine max) in the U.S. Crop loss due to aphid infestation is estimated annually at $3.6-$4.9 billion. Current management strategies include scouting, genetic control and chemical control, all of which are time consuming and expensive. Host Plant Resistance (HPR) provides an attractive alternative to control aphid populations by suppressing their growth and reproduction in plants. The discovery of several Rag genes (Resistance to Aphis glycines, 1-6) in soybean has allowed breeders to develop and deploy soybean aphid-resistant cultivars. However, the mechanisms of resistance associated with the Rag genes are yet to be identified. The plant introduction (PI) 567301B contains the Rag5 gene that confers antixenotic resistance indicating the presence of a host factor that alters insect behavior resulting in poor aphid performance. PI 563701B plants display resistance to aphids in whole plant assays and not in detached leaf assays suggesting that Rag5-mediated resistance is systemic and is induced in plant sections other than leaves. In this study, the source of Rag5-mediated resistance was identified as the stem. Furthermore, treatment of PI 567301B detached leaves with kaempferol resulted in reduced aphid populations. Electrical penetration graph studies do not show a vast difference between aphid feeding behavior on PI 567301B whole plants and detached leaves thus indicating that kaempferol glycoside maybe the cause of Rag5 resistance.
Degree
M.S.
Advisors
Nalam, Purdue University.
Subject Area
Botany|Plant Pathology
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