RNAi Knockdown of a Salivary Transcript Leading to Lethality in the Pea Aphid,Acyrthosiphon pisum

Abstract

Injection of siRNA (small interfering RNA) into parthenogenetic adult pea aphids (Acyrthosiphon pisum) is shown here to lead to depletion of a target salivary gland transcript. The siRNA was generated from double stranded RNA that covered most of the open reading frame of the transcript, which we have called Coo2. The Coo2 transcript level decreases dramatically over a 3-day period after injection of siRNA. With a lag of 1 to 2 days, the siCoo2-RNA injected insects died, on average 8 days before the death of control insects injected with siRNA for green fluorescent protein. It appears, therefore, that siRNA injections into adults will be a useful tool in studying the roles of individual transcripts in aphid salivary glands and suggests that siCoo2-RNA injections can be a useful positive control in such studies.

Predicted Effector Molecules in the Salivary Secretome of the Pea Aphid (Acyrthosiphon pisum): A Dual Transcriptomic/Proteomic Approach

“…One of these proteins, C002 (ACYPI008617), is known to be secreted by the pea aphid during feeding and is necessary for successful feeding on plants. 29,33 The putative salivary sheath protein SHP 28 was also identified in both the enriched EST library and the salivary gland proteome. Two…”

“…Aphids initially secrete a gelling saliva that hardens and forms a protective sheath around the mouthparts, followed by watery saliva which is secreted into the phloem immediately before and during feeding but also into cells as the tip of the mouthparts progress toward the phloem. 21,22 A number of strategies have been employed in an attempt to catalogue and characterize the salivary proteins of various aphid species and include mass spectrometry of collected saliva, 27,28 RNA interference, 29 salivary gland EST analysis, 30 in planta analysis of phloem occlusion mechanisms, 23 plant differential gene expression studies 31 in response to aphid salivary concentrates and in planta expression of candidate salivary effector proteins. 32 The availability of a genome sequence for the pea aphid, Acyrthosiphon pisum, has made this species a particularly good candidate for saliva studies.…”

Aphids alter host-plant nitrogen isotope fractionation

“…It is known that aphid feeding relocates nitrogen within host plants (34,35) and reduces host nitrogen content (30). It is also known that aphids return nitrogen in the form of proteins back to host plants during feeding (26,27,36) and that host-plant responses to feeding by some aphids include measureable changes in the host phloem sap amino acid profile (e.g., refs. 37, 38).…”

“…Movement of nitrogen in this fluid-feeder/host system mostly occurs up the food chain, but some nitrogen, in the form of aphid-derived proteins delivered in watery saliva during aphid feeding, moves in the reverse direction, from fluid-feeder back to host (e.g., refs. [25][26][27].…”

Gene expression in plant according to RNAi treatment of the tobacco whitefly

“…이러한 약제저항성 문제로 인해 미생물농약, 천적, 식물 essential oil, 곤충병원성 곰팡이 등과 같은 생물적 방제방 어 왔지만 (Mutti et al, 2006;Rangasamy and Siegfried, 2012;Sapountzis et al, 2014;Wynant et al, 2014), 위의 두 적용방법 모두 해충방제에 직접 적용하기에 무리가 있 는 방법들이다. 이러한 문제로 인해 최근에는 방제대상 곤 충의 dsRNA를 발현시키는 transgenic plant에 대한 연구가 이루어지고 있다 (Bhatia et al, 2012;Mao et al, 2007).…”