title: RNA Interference of Odorant-Binding Protein 2 (OBP2) of the Cotton Aphid, Aphis gossypii (Glover), Resulted in Altered Electrophysiological Responses.
abstract: Aphis gossypii (Glover) (Hemiptera: Aphididae) is a highly invasive pest that feeds primarily on phloem resulting in severe economic loss to growers. A. gossypii has cosmopolitan distribution with broad host range, polyphenism, parthenogenetic mode of reproduction, vectoring abilities, and host alteration which has profound influence on its management. Odorant-binding proteins (OBPs) in insects are involved in olfaction, playing a key role in orienting the insect for feeding or oviposition. Recent studies revealed that OBP2 is found in both sensilla trichodea and sensilla basiconica and is preferentially binds to plant volatiles, thus playing crucial roles in host-seeking, detection of oviposition attractants, etc., However, information about the role of OBP2 in A. gossypii (AgOBP2) is still unavailable. In this study, we cloned and characterized OBP2, ortholog from A. gossypii, and the full-length AgOBP2 complementary DNA (cDNA) consisted of 859 bp with an open reading frame of 732 bp. Phylogenetic analysis resulted in grouping of AgOBP2 protein with members of the tribe Aphidini. Further, diet-mediated delivery of double-stranded RNA for AgOBP2 induced silencing, which was evaluated at 48 and 96 h. The reverse transcriptase real-time quantitative polymerase chain reaction (RTq-PCR) results revealed that the level of AgOBP2 messenger RNA (mRNA) was significantly reduced (55-77 %) in dsAgOBP2 treatment after 96 h as compared to the untreated control. The same was reiterated by the electrophysiological responses in the aphids which was reduced (>50 % at 0.25 μg/μl concentration) as compared to the untreated control. Thus, our results showed the potential of gene silencing, possibly to interfere with the odorant perception of A. gossypii for RNAi-mediated pest management. The results from our study provided the first evidence that AgOBP2 play crucial roles in host-seeking, detection of oviposition attractants, etc.; as a result, we suggests that OBP2 could potentially serve as a practicable target for RNAi-mediated gene silencing in hemipteran insect pest control.
authors.affiliation: Division of Biotechnology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore, 560 089, India. rebijith@gmail.com.
authors.forename: K B
authors.initials: KB
authors.lastname: Rebijith
authors.affiliation: Division of Biotechnology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore, 560 089, India. asokaniihr@gmail.com.
authors.forename: R
authors.initials: R
authors.lastname: Asokan
authors.affiliation: Division of Biotechnology, Indian Institute of Horticultural Research, Hessaraghatta Lake Post, Bangalore, 560 089, India. ranjithahande@gmail.com.
authors.forename: H Ranjitha
authors.initials: HR
authors.lastname: Hande
authors.affiliation: Division of Horticultural Science, Indian Council of Agricultural Research (ICAR), New Delhi, 110 012, India. ddghort@gmail.com.
authors.forename: N K Krishna
authors.initials: NK
authors.lastname: Kumar
authors.affiliation: Department of Biotechnology and Bioinformatics, Kuvempu University, Shivamoga, 577 451, India. krishnav@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Krishna
authors.affiliation: Division of Insect Physiology, National Bureau of Agriculturally Important Insects, Bangalore, 560 024, India. vinusumathi@gmail.com.
authors.forename: J
authors.initials: J
authors.lastname: Vinutha
authors.affiliation: Division of Insect Physiology, National Bureau of Agriculturally Important Insects, Bangalore, 560 024, India. rmenon101@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Bakthavatsalam
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids / Q000145:classification / Q000235:genetics / Q000502:physiology*; D020868:Gene Silencing; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010572:Pest Control, Biological; D010802:Phylogeny; D034622:RNA Interference; D018035:Receptors, Odorant / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
chemical_list: D019476:Insect Proteins; D018035:Receptors, Odorant; C045648:odorant-binding protein
keywords: Aphis gossypii; Gene silencing; Invasive; Odorant-binding proteins; Oviposition; RNAi