Polymorphisms in salivary‐gland transcripts of Russian wheat aphid biotypes 1 and 2

Abstract

The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko) (Homoptera: Aphididae), is a major pest of small grains. As with plant‐feeding aphids in general, the interaction between RWA and host plants is governed, on the insect side, by proteins and enzymes in saliva. In this work, we examined sequence variations in transcripts encoding proteins and enzymes of RWA salivary glands. We conducted reverse transcription – polymerase chain reaction in RWA biotypes 1 and 2 using primers derived from pea aphid orthologs, and cloned regions of 17 putative salivary gland transcripts. For four of the transcripts, we observed no difference in sequences between the two biotypes. For the other 13 transcripts, for example, the transcripts encoding sucrase, trehalase and protein C002, large amount of variations, both within each biotype and between the two biotypes, were observed. Usually the two biotypes shared only one variant, which was typically the most common variant in both biotypes. Most of the transcripts had more non‐synonymous than synonymous codon changes among their variants. Our results offer possible molecular markers for distinguishing the two biotypes and insights into their evolution.

Proteomic Profiling of Cereal Aphid Saliva Reveals Both Ubiquitous and Adaptive Secreted Proteins

“…The secretion of trehalase into the plant host may provide a mechanism for the aphid to disrupt a potentially threatening signal transduction system. Considerable variation exists among virulent and avirulent biotypes of D. noxia at the proteomic and mRNA transcript/sequence levels [27], [48] suggesting that further studies into the putative role of trehalase as a secreted aphid effector are warranted.…”

Adaptation to Nicotine Feeding in Myzus persicae

“…Out of all differentially expressed genes, predicted sucrases and α-amylases are among those most highly induced by nicotine, with 12- to 14-fold increases in gene expression. Several proteomic studies have identified secreted aphid salivary proteins (Carolan et al, 2011; Carolan et al, 2009; Cooper et al, 2010; Cooper et al, 2011; Cui et al, 2012; Harmel et al, 2008b; Nicholson et al, 2012; Rao et al, 2013; Will et al, 2012). Expression of some of secreted aphid salivary genes is regulated by the host plants on which M. persicae are feeding (Elzinga et al, 2014).…”

A multi‐genome analysis approach enables tracking of the invasion of a single Russian wheat aphid (Diuraphis noxia) clone throughout the New World

“…It has been hypothesized that rapid evolution of RWA salivary proteins may be responsible for the adaptation to these resistant lines (Cui et al . ). With genomics resources now available for many aphid species, the opportunity now exists to examine in more detail the relative contribution of plasticity vs. adaptation in underpinning aphid invasion success.…”