title: Expression of small RNA in Aphis gossypii and its potential role in the resistance interaction with melon.
abstract: BACKGROUND
  The regulatory role of small RNAs (sRNAs) in various biological processes is an active area of investigation; however, there has been limited information available on the role of sRNAs in plant-insect interactions. This study was designed to identify sRNAs in cotton-melon aphid (Aphis gossypii) during the Vat-mediated resistance interaction with melon (Cucumis melo).
  
  
  RESULTS
  The role of miRNAs was investigated in response to aphid herbivory, during both resistant and susceptible interactions. sRNA libraries made from A. gossypii tissues feeding on Vat⁺ and Vat⁻ plants revealed an unexpected abundance of 27 nt long sRNA sequences in the aphids feeding on Vat⁺ plants. Eighty-one conserved microRNAs (miRNAs), twelve aphid-specific miRNAs, and nine novel candidate miRNAs were also identified. Plant miRNAs found in the aphid libraries were most likely ingested during phloem feeding. The presence of novel miRNAs was verified by qPCR experiments in both resistant Vat⁺ and susceptible Vat⁻ interactions. The comparative analyses revealed that novel miRNAs were differentially regulated during the resistant and susceptible interactions. Gene targets predicted for the miRNAs identified in this study by in silico analyses revealed their involvement in morphogenesis and anatomical structure determination, signal transduction pathways, cell differentiation and catabolic processes.
  
  
  CONCLUSIONS
  In this study, conserved and novel miRNAs were reported in A. gossypii. Deep sequencing data showed differences in the abundance of miRNAs and piRNA-like sequences in A. gossypii. Quantitative RT-PCR revealed that A. gossypii miRNAs were differentially regulated during resistant and susceptible interactions. Aphids can also ingest plant miRNAs during phloem feeding that are stable in the insect.
authors.affiliation: College of Agricultural Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America. sus56@psu.edu
authors.forename: Sampurna
authors.initials: S
authors.lastname: Sattar
authors.forename: Charles
authors.initials: C
authors.lastname: Addo-Quaye
authors.forename: Yan
authors.initials: Y
authors.lastname: Song
authors.forename: James A
authors.initials: JA
authors.lastname: Anstead
authors.forename: Ramanjulu
authors.initials: R
authors.lastname: Sunkar
authors.forename: Gary A
authors.initials: GA
authors.lastname: Thompson
mesh_terms: D000818:Animals; D001042:Aphids / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D001483:Base Sequence; D028463:Cucumis melo / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation; D035683:MicroRNAs / Q000235:genetics; D010940:Plant Proteins / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D017423:Sequence Analysis, RNA
chemical_list: D035683:MicroRNAs; D010940:Plant Proteins; D018749:RNA, Plant; D034741:RNA, Small Interfering