Expression Profiling and Functional Analysis of Candidate Odorant Receptors in Galeruca daurica

Abstract

Galeruca daurica (Joannis) is an oligophagous pest in the grasslands of Inner Mongolia, China, which feed mainly on Allium spp. Odorant receptors (ORs) play an important role in the olfactory system in insects, and function together with olfactory co-receptor (ORco). In this study, 21 OR genes were identified from the transcriptome database of G. daurica adults, and named GdauOR1-20 and GdauORco. The expression profiles were examined by RT-qPCR and RNA interference (RNAi) and electroantennogram (EAG) experiments were conducted to further identify the olfactory functions of GdauOR4, GdauOR11, GdauOR15, and GdauORco. It was found that 15 GdauORs (OR1, OR3-6, OR8, OR11-13, OR15, OR17-20, and ORco) were mainly expressed in antennae, and the expression levels of GdauORs in adults were affected by age. When GdauOR4, GdauOR15, and GdauORco were silenced by RNAi, the electrophysiological responses to host plant volatiles were significantly decreased in G. daurica. This study lays a necessary foundation for clarifying the mechanism on finding host plants in G. daurica.

Evaluation of the Toxicity of Chemical and Biogenic Insecticides to Three Outbreaking Insects in Desert Steppes of Northern China

“…In recent years, outbreaks of O. asiaticus, M. palpalis, and G. daurica have become frequent in the northern China steppes due to livestock overgrazing, extreme climate change, and consequent land desertification [33,37]. These pest species prefer to live on heavilygrazed steppes and mainly feed on gramineaceous and liliaceous plants such as stipa, wild rye, and allium [16,27,28]. The outbreaks have brought remarkable grass yield losses and led to grassland deterioration, thereby adversely affecting animal husbandry production and the development of the grassland industry.…”

“…The leaf beetle, G. daurica, feeds exclusively on Allium species (Liliaceae) in the desert steppes of the Inner Mongolia grasslands in China [25]. Sudden outbreaks of this pest were initially reported to have caused great losses to pasture in 2009 and damage has increased extensively year by year [26][27][28]. These three key insects have one generation annually and over winter lay eggs, which hatch in spring when the pastures turn green and grow.…”

MicroRNA miR‐285 modulates the metamorphosis in Galeruca daurica by targeting Br‐C

“…Since its abrupt outbreak in 2009, it has caused serious damage to grasslands 34,35 . Previous studies on this pest have mainly focused on host plants, 35 life history, 36 genetic diversity, 37,38 cold resistance, 39–42 olfaction, 43–45 diapause, 46–50 and miRNAs 51–53 . More recently, Duan et al .…”

“…Since its abrupt outbreak in 2009, it has caused serious damage to grasslands. 34,35 Previous studies on this pest have mainly focused on host plants, 35 life history, 36 genetic diversity, 37,38 cold resistance, [39][40][41][42] olfaction, [43][44][45] diapause, [46][47][48][49][50] and miRNAs. [51][52][53] More recently, Duan et al verified that two miR-NAs, let-7-5p and miR-2765-3p, modulated the reproductive diapause of this beetle through targeting Kr-h1 and FoxO, respectively.…”