PRJNA478017
Glycine max Transcriptome or Gene expression
Soybean aphids are phloem feeding insect pests of soybean. Aphids divert plant assimilates for their nutrition, causing yield losses of up to 50%. One of the management options for soybean aphids is cultivation of resistant soybean varieties. Aphid resistance in soybean is conferred by Resistance to Aphis glycines (Rag) genes with Rag1 and Rag2 being the most studied to date. Under insect attack, plants respond by inducing defenses which primarily consist of morphological, biochemical and molecular mechanisms. Previous studies showed that aphid populations were significantly lower in the double pyramid (Rag1Rag2) genotypes compared to soybean genotypes that contained the Rag1 or Rag2 gene alone. We hypothesized that pyramiding Rag1 and Rag2 in one soybean genotype had an additive or synergistic effect on aphid resistance at the molecular level. To test this idea, the transcriptional response of four near isogenic soybean genotypes (one aphid-susceptible and three aphid-resistant: Rag1, Rag2 and Rag1Rag2) to aphid feeding was measured at 6 and 12 hours, using RNA sequencing. Comparison of mock-treated samples versus aphid-treated samples for each soybean genotype showed that the transcriptional response to feeding by soybean aphids involved unique sets of genes and shared genes respectively at both time points. Biological processes modified due to aphid feeding were distinctive for each of the soybean genotypes at 6 hours but similar among them at the 12 hour time point. The transcriptional response of the Rag1Rag2 soybean genotype to feeding by soybean aphids at both time points involved unique sets of genes that were absent in the Rag1 or Rag2 response; suggesting that pyramiding the Rag1 and Rag2 genes in one soybean genotype has a synergistic effect on aphid resistance at the molecular level. This research will build the knowledge base on aphid resistance, contributing to better management of soybean aphids and optimization of soybean yields.