The relative expression of <i>Helicoverpa armigera</i> HMGR (HaHMGR) and vitellogenin in <i>H.</i><i>armigera</i> after injecting dsRNA.

<p>(A) Histograms represent the expression of HaHMGR after injecting HaHMGR double-stranded RNA (dsHaHMGR). (B) The expression of vitellogenin after injecting dsHaHMGR. The enhanced green fluorescent protein double-stranded RNA (dsEGFP) treatment group was used as a negative control, and nuclease-free water was used as a blank control. Values with the same letter are not significantly different at the <i>P</i>>0.05 level (ANOVA followed by Tukey’s post-hoc test).</p

Effect of dsHaHMGR on fecundity, larval production and number of spermatophores in <i>Helicoverpa armigera</i>.

<p>Two-day-old female pupae were treated with 1 µg of HaHMGR double-stranded RNA (dsHaHMGR) or enhanced green fluorescent protein double-stranded RNA (dsEGFP) (negative control). One female treated with dsRNA (dsHaHMGR or dsEGFP) was paired with an untreated male in a small cage (N = 30). Values are expressed in absolute terms as a percentage or as the mean ± SD. Values with the same letter are not significantly different at the <i>P</i>>0.05 level (ANOVA followed by Tukey’s post-hoc test).</p

Neighbor-joining phylogenetic tree of the amino acid sequences of HMGR by Molecular Evolutionary Genetics Analysis Software Version 4.0 (MEGA4).

<p>The branches were statistically evaluated by bootstrap analysis. All sequences were from GenBank.</p

Effects of <i>Helicoverpa armigera</i> HMGR (HaHMGR) RNA interference (RNAi) on the oviposition of <i>H.</i><i>armigera</i>.

<p>Twenty dsRNA-treated or nuclease-free water-treated females were mated with untreated males in cages (40 cm×30 cm×30 cm). The enhanced green fluorescent protein double-stranded RNA (dsEGFP) treatment group was used as a negative control. Nuclease-free water was used as a blank control. Histograms represent the average oviposition per female. Values with the same letter are not significantly different at the <i>P</i>>0.05 level (ANOVA followed by Tukey’s post-hoc test).</p

RNAi Silencing of the HaHMG-CoA Reductase Gene Inhibits Oviposition in the <i>Helicoverpa armigera</i> Cotton Bollworm

<div><p>RNA interference (RNAi) has considerable promise for developing novel pest control techniques, especially because of the threat of the development of resistance against current strategies. For this purpose, the key is to select pest control genes with the greatest potential for developing effective pest control treatments. The present study demonstrated that the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase; HMGR) gene is a potential target for insect control using RNAi. HMGR is a key enzyme in the mevalonate pathway in insects. A complete cDNA encoding full length HMGR (encoding an 837-aa protein) was cloned from <i>Helicoverpa armigera</i> (Lepidoptera: Noctuidae). The HaHMGR (<i>H. armigera</i> HMGR) knockdown using systemic RNAi <i>in vivo</i> inhibited the fecundity of the females, effectively inhibited ovipostion, and significantly reduced vitellogenin (Vg) mRNA levels. Moreover, the oviposition rate of the female moths was reduced by 98% by silencing HaHMGR compared to the control groups. One-pair experiments showed that both the proportions of valid mating and fecundity were zero. Furthermore, the HaHMGR-silenced females failed to lay eggs (approximate 99% decrease in oviposition) in the semi-field cage performance. The present study demonstrated the potential implications for developing novel pest management strategies using HaHMGR RNAi in the control of <i>H. armigera</i> and other insect pests.</p></div

Comparison of gene expression level between the two libraries.

<p>For comparing gene expression level between the two libraries, each library was normalized to 1 million tags. Red dots represent transcripts more prevalent in the phenol treatment library, green dots show those present at a lower frequency in the infected tissue and blue dots indicate transcripts that did not change significantly. The parameters “FDR<0.001” and “log2 Ratio≥1” were used as the threshold to judge the significance of gene expression difference.</p

Length distribution of non-redundant consensus sequences.

*<p>N50 = median length of all unigenes; **Mean size = average length of all unigenesGO and COG classification</p

Primers used in Real-time RT-PCR.

<p>Primers used in Real-time RT-PCR.</p

Differentially expressed genes in phenol tissue library.

<p>The “X” axis represents fold-change of DEGs in the PT library. The “y” axis represents the number of unique tags (log 10).</p

Summary for the <i>Chironomus kiiensis</i> transcriptome in phenol treated (PT) and control (CK) libraries.

<p>Summary for the <i>Chironomus kiiensis</i> transcriptome in phenol treated (PT) and control (CK) libraries.</p