微RNA (microRNAs,miRNA)、小干扰RNA (small interfering RNA,siRNA) 是真核生物体内触发RNA干扰 (RNA interference,RNAi) 的两种非编码小RNA。两种非编码RNA生物合成通路在黑腹果蝇、埃及伊蚊、家蚕以及其他昆虫中具有广泛研究，但在膜翅目昆虫尤其是寄生蜂中少见。蝶蛹金小蜂是蝴蝶蛹期寄生蜂。本研究通过蝶蛹金小蜂基因组对miRNA、siRNA合成通路鉴定并分析。结果表明除siRNA通路中R2D2、Argonaute-2基因在基因组中分别具有2、3个拷贝，两个通路其他关键基因均只有1个拷贝。结构域保守性分析表明蝶蛹金小蜂相关蛋白与其他物种同源蛋白具有相似结构。对膜翅目昆虫Dicer、Argonaute基因进化分析表明siRNA通路相关基因进化速率更快。但与其他膜翅目昆虫相反，蝶蛹金小蜂中Dicer-2基因进化速率比Dicer-1基因更低。表达分析显示miRNA通路基因在蝶蛹金小蜂成虫中表达量更高而siRNA通路基因表达模式各不相同。本研究为了解寄生蜂miRNA、siRNA生物合成通路及其作用机制提供新的认识。

    Various rice lines have been genetically modified with genes from Bacillus thuringiensis (Bt) to continuously produce Bt insecticidal proteins against lepidopteran larvae. The Bt insecticidal protein constantly expresses in the plants to create an opportunity for non-target herbivores to acquire and convey the protein to their predators or parasitoids across trophic levels. This paper evaluates the effects of Bt rice (namely, Kemindao 1 (KMD1) and Kemindao 2 (KMD2)) expressing Cry1Ab as compared to its non-Bt control line, Xiushui 11 on non-target predator Orius tantilus (a generalist predatory anthocorid of thrips) under laboratory and field conditions. To measure several biological parameters such as total nymphal duration and fecundity of this bug, it was reared on thrips and pollens of KMD1 and KMD2 as compared to their control under laboratory conditions. By comparison with the control, Bt rice did not significantly affect main life-history characteristics (total nymphal duration, female adult longevity, oviposition period and fecundity) of this anthocorid preying on Bt rice-fed thrips along with Bt rice pollens, except that the fecundity of this predator for KMD1 was distinctly lower as compared with KMD2 or the control. Enzyme-linked immunosorbent assay (ELISA) results showed that no Cry1Ab protein was detected in this predator fed on thrips or rice pollen from Bt rice but was in Bt rice pollens. With the beat plate, plastic bag and color trap sampling methods, two-year field monitoring of O. tantilus abundance demonstrated that Bt rice had no significant detrimental effects on the population dynamics and seasonal average densities of this predatory anthocorid as compared with the control. Thus, it is suggested that growing our tested Bt rice (KMD1 and KMD2) producing Cry1Ab will pose a negligible risk to the anthocorid, O. tantilus.

   The whitefly Bemisia tabaci is a species complex, of which two invasive species, called MEAM1 and MED whiteflies, have invaded many parts of the world in the past 30 years and replaced native whitefly populations in many regions of invasions including many areas in China. One of the possible reasons for the invasion is that MEAM1 and MED whiteflies are more fecund than the native species. However, factors that affect reproduction and the molecular mechanism of vitellogenesis among various B. tabaci cryptic species are not clearly known. In this study, cDNAs of vitellogenin (Vg) genes were sequenced from native B. tabaci Asia II 1 and invasive B. tabaci MED in China. The deduced amino acid sequences were 2 182 residues in Asia II 1 and 2 217 residues in MED. Compared to the Vg gene cDNA sequence of Asia II 1 species, the Vg gene in MED could be cleaved at least into four subunits, with deduced molecular weight of 50, 90, 150 and 190 kDa, respectively. However, only two different subunits were cleaved between residues 459 and 460 in the Asia II 1. In addition, more than two serine-rich stretches located in both the N-terminal and the C-terminal region in invasive species. More GHN domains were revealed only in the N-terminal region of B. tabaci MED. Vg gene expression pattern was characterized using quantitative real-time (qRT)-PCR to compare the dynamic of vitellogenin gene mRNA level. Vg gene transcription reached the peak level at 13 d after eclosion in B. tabaci Asia II 1, 3 d later than that in MED and another invasive species of the B. tabaci complex MEAM1. We assumed that the present difference of Vg gene expression pattern is due to the different regulation pattern of vitellogenesis among species of the B. tabaci complex. These results provide useful information to reveal the mechanisms of reproduction in whitefly species complex.

Numerous Bt rice lines expressing Cry protein derived from Bacillus thuringiensis Berliner (Bt) have been developed since 1989. However, the potential risks posed by Bt rice on non-target organisms still remain debate. The white-backed planthopper (WBPH), Sogatella furcifera (Horváth), is one of the most economically important insect pests of rice in Asian countries and also one of the main non-target herbivores of transgenic rice. In the current study, impacts of transgenic cry1Ab/vip3H+epsps rice (G6H1) with both insect and herbicide resistance on WBPH were evaluated to ascertain whether this transgenic rice line had potential risks for this sap-sucking pest under laboratory and field conditions. The laboratory results showed that no significant difference in egg developmental duration, nymphal survival rate and female fecundity was found for WBPH between G6H1 and its non-transgenic isoline (XS110). However, the development duration of nymphs was significantly shorter and female longevity significantly longer when WBPH fed on G6H1 by comparison with those on its control. To verify the results found in laboratory, a 3-yr field trial was conducted to monitor WBPH population using both the vacuum-suction machine and beat plate methods. Although the seasonal density of WBPH nymphs and total density of nymphs and adults were not significantly affected by transgenic rice regardless of the sampling methods, the seasonal density of WBPH adults in transgenic rice plots was slightly lower than that in the control when using the vacuum-suction machine. Based on these results both from laboratory and field, it is clear that our tested transgenic rice line will not lead higher population of WBPH. However, long-term field experiments to monitor the population dynamics of WPBH at large scale need to be conducted to confirm the present conclusions in future.

A 2-yr field study was conducted to assess the effects of transgenic japonica rice (KMD1 and KMD2) with a synthetic cry1Ab gene from Bacillus thuingiensis Berliner on population dynamics and seasonal average densities of five thrips species including Stenchaetothrips biformis (Bagnall), Frankliniella intonsa (Trybom), F. tenuicornis (Uzel), Haplothrips aculeatus (Fabricius), Haplothrips tritici (Kurd) and their general predatory flower bug, Orius similis Zheng as compared to the parental control rice line using the white, blue and yellow sticky card traps. Population dynamics and seasonal average densities of these five thrips species and their general predatory flower bug were not significantly affected by rice type. Additionally, the white sticky card trap was suggested to be the most suitable for monitoring the population of these five thrips species and their general predator. These results show that our tested Bt rice lines do not interrupt the population of non-target thrips species and their general predatory flower bug in the field, and also cannot result in more occurrence of these thrips species in the rice ecosystem.

Chlorantraniliprole was introduced into China from 2008 as a novel insecticide to control the rice stem borer, Chilosuppressalis (Walker). Cotesia chilonis (Matsumura) is the major parasitoid of C. suppressalis. We collected sevenpopulations of C. suppressalis and two populations of C. chilonis in different locations in China in 2009 to investigate thelethal effects of chlorantraniliprole on them. The populations of C. suppressalis from different regions showed variousLD50 values ranging from 2.00 to 18.70 ng per larva. Chlorantraniliprole has negligible acute contact toxicity (LC50>500 mgL-1) to C. chilonis and its oral toxicity is also much lower than that of fipronil (>2 800-fold difference in LC50). The resultsindicated that chlorantraniliprole is a good alterative in rice integrated pest management (IPM) programs. The susceptibilitydata of C. suppressalis will be useful for monitoring resistance levels in future.