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ARS Home » Midwest Area » Wooster, Ohio » Corn, Soybean and Wheat Quality Research » Research » Publications at this Location » Publication #302260
Title: Soybean aphid feeding on resistant soybean leads to induction of xenobiotic stress response and suppression of salivary effector genes

Author
item BANSAL, RAMAN - The Ohio State University
item Mian, Rouf
item MICHEL, ANDREW - The Ohio State University

Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2014
Publication Date: 11/16/2014
Citation: Bansal, R., Mian, R.M., Michel, A.P. 2014. Soybean aphid feeding on resistant soybean leads to induction of xenobiotic stress response and suppression of salivary effector genes. BMC Genomics. 15:972.

Interpretive Summary: The soybean aphid is a serious threat to soybean production in Asia and North-America. Host plant resistance (HPR) is an economic and environmentally sustainable method for controlling the soybean aphids. To date, 6 major soybean genes for HPR to soybean aphids have been identified, including Rag1, which is available in commercial cultivars. How soybean aphids molecularly respond to feeding on resistant soybean is unknown, but it could provide clues as to how this insect adapts to HPR. Here, we measured the impact of Rag1 soybean aphid resistance gene on the gene expression of an avirulent biotype of the aphid. We performed next generation RNA-Sequencing to compare and contrast aphid gene expression when fed on near isogenic soybean lines: one with Rag1 (resistant) and the other without (susceptible). Statistical analysis revealed 914 genes with significant differential expression among aphids on resistant and susceptible plants. Most genes with higher expression in aphids on resistant plants were related to stress and detoxification. Genes down-regulated in aphids on resistant plants included genes for infection-promoting effectors present in aphid saliva. The differential expression observed in aphid feeding on Rag1 soybean resembled a pattern typical of xenobiotic challenge. Our data validated the ‘antibiosis’ mode of Rag1 HPR, presumably mediated through toxic secondary metabolites. Additionally, this study identified many aphid genes and gene families at the forefront of its molecular interaction with soybean and further investigation of such interactions using other soybean aphid biotypes may reveal adaptation. Findings from this study will be useful for developing soybean germplasm with aphid resistance.

Technical Abstract: The soybean aphid, Aphis glycines, poses serious challenges to soybean production in Asia, where it is native, and North-America, where it is invasive. To date, 6 major soybean genes for host plant resistance (HPR) to A. glycines have been identified, including Rag1, which is available in commercial cultivars. How A. glycines molecularly responds to feeding on resistant soybean is unknown, but it could provide clues as to how this insect adapts to HPR. Here, we measured the impact of Rag1 soybean on the gene expression of an avirulent biotype of A. glycines. We performed next generation RNA-Sequencing to compare and contrast A. glycines gene expression when near isogenic soybean lines: one with Rag1 (resistant) and the other without (susceptible). Statistical analysis revealed 914 genes (out of a total of 64,860 transcripts) with significant differential expression among A. glycines on resistant and susceptible plants. Most genes with higher expression in A. glycines on resistant plants (N=352) were related to stress and detoxification such as cytochrome P450, glutathione-S-transferase, carboxyesterase, and ABC transporter enzymes. Genes down-regulated in A. glycines on resistant plants (N=562) included genes for infection-promoting effectors present in A. glycines saliva. The differential expression observed in A. glycines feeding on Rag1 soybean resembled a pattern typical of xenobiotic challenge. Our data validated the ‘antibiosis’ mode of Rag1 HPR, presumably mediated through toxic secondary metabolites. Additionally, this study identified many A. glycines genes and gene families at the forefront of its molecular interaction with soybean and further investigation of such interactions using other soybean aphid biotypes may reveal adaptation.