Comparative Transcriptional Analysis of the Host-Specialized Aphids Aphis gossypii (Hemiptera: Aphididae)

Abstract

Host specialization is an ubiquitous character in aphid populations. Many polyphagous aphid populations usually consist of several subpopulations that have strong fidelity to a specific host or a subset of host range. Host specialization is an evolutional result of food habit of insects. However, genetic basis and molecular mechanism of host specialization are still unclear. In this study, we presented a comparative analysis on global gene expression profiles of three lineages of Aphis gossypii Glover: cotton-specialized (CO), cucurbit-specialized (CU), and CU reared on cowpea (CU-cowpea), using RNA-Seq method. More than 157 million clean reads and 38,398 different unigenes were generated from transcriptomes of these three aphid lineages. The 1,106 down- and 2,835 up-regulated genes were found between CO and CU, and 812 down- and 14,492 up-regulated genes between CU-cowpea and CU. Differentially expressed genes between CO and CU were enriched in sugar metabolism, immune system process, pathogen infection or symbiosis, and salivary secretion. Genes associated with cytochrome P450, major facilitator superfamily, and salivary effector were differentially expressed between CO and CU, which might be involved in determining host specialization. UDP-glycosyltransferases genes were sensitive to host shift. Carboxylesterases and digestion-related protease genes were related to both the host specialization and host shift of aphids. Expression levels of 22 out of 24 genes of CO and CU measured by RT-qPCR method were as similar as the results from RNA-seq method. This study provides a road map for future study on molecular mechanism of host specialization in aphids.

The molecular mechanisms that determine different degrees of polyphagy in the Bemisia tabaci species complex

“…However, more than 15,000 genes (>40%) were found to be differentially expressed when these two populations were compared to the population feeding on the novel host cowpea. This time, the differentially expressed genes were mostly enriched in the KEGG super-pathways "organismal systems" and "cellular processes," indicating a significant stress-response (Zhang et al, 2017). It is interesting to note that this response was quite similar in its characteristics to the non-adaptive plastic response that "Type IV" B. tabaci species presented when switching to feed on a novel/non-suitable host plants ( Figure S3d), raising the possibility for the existence of an hemipteran common "stress-response tool-box.…”

Transcriptome profiling revealed potentially important roles of defensive gene expression in the divergence of insect biotypes: a case study with the cereal aphid Sitobion avenae

“…RNA extraction and cDNA synthesis for each sample were conducted following the above-mentioned method. The gene NADH was chosen as the reference gene because of its consistent expression in all samples in this study and in our previous studies [ 96 ]. Specific primers for each gene were designed by using Beacon Designer version 8.0 (Premier Biosoft, Palo Alto, CA) (Table S 6 ).…”

“…Specific primers for each gene were designed by using Beacon Designer version 8.0 (Premier Biosoft, Palo Alto, CA) (Table S 6 ). As described in [ 96 ], 20 μL volume reactions contained 10 μL SYBR Premix Ex Taq II (TaKaRa), 2 μL cDNA, 1 μL each forward and reverse primer (10 μM), and 6 μL ddH2O. All qRT-PCR reactions were performed on a Roche LightCycler® 480 II system (Roche Diagnostics Ltd., Rotkreuz, Switzerland).…”

Elevated rates of positive selection drive the evolution of pestiferousness in the Colorado potato beetle (Leptinotarsa decemlineata, Say)

“…High rates of positively selected genes in CPB, L. tumamoca and L. peninsularis , are notable as these species expanded onto host plants, with L. tumamoca and L. peninsularis expanding into families outside of Solanaceae (Jolivet et al 1988). Recent experiments have shown dramatic regulatory changes in detoxification pathways following host shifts in plant‐feeding arthropods (Dermauw et al., 2013; Govind et al., 2010; Müller et al., 2017; Yu et al., 2016; Zhang et al., 2017). Additionally, other comparative genomic studies have found similar evidence of positive selection in detoxification genes related to host plant utilization (Simon et al., 2015; Gloss et al, 2019; Okamura et al., 2019).…”