anjiang tan yongping huang

Understanding the mechanism of Bt resistance is one of the key elements of the effective application of Bt in pest control. The lepidopteran model insect, the silkworm, demonstrates qualities that make it an ideal species to use in achieving this understanding. We screened 45 strains of silkworm (Bombyx mori) using a Cry1Ab toxin variant. The sensitivity levels of the strains varied over a wide range. A resistant strain (P50) and a phylogenetically related susceptible strain (Dazao) were selected to profile the expressions of 12 Bt resistance-related genes...

MicroRNAs (miRNAs) are a class of endogenous, non-coding, regulatory RNA molecules that post-transcriptionally regulate gene expression by binding to the 3'UTRs of mRNA targets and thus cause their degradation or translational inhibition. In insects, important roles of miRNAs in various biological processes have been demonstrated in Drosophila melanogaster. However, biological roles of miRNAs are barely unveiled in the majority of insect species due to limited genetic tools. In the present study, we introduce the transgenic miRNA sponge (miR-SP) technology combining with the binary GAL4/UAS system in the domesticated silkworm, Bombyx mori, to exploit the biological function of an evolutionally conserved miRNA, let-7...

The PAR-domain protein 1 (PDP1) is essential for locomotor activity of insects. However, its functions in insect growth and development have not been studied extensively, which prompted our hypothesis that PDP1 acts in energy metabolism. Here we report identification of TcPDP1 in the red flour beetle, Tribolium castaneum, and its functional analysis by RNAi. Treating larvae with dsTcPDP1 induced pupae developmental arrestment, accompanied by accelerated fat body degradation. dsTcPDP1 treatments in adults resulted in reduced female fecundity...

Insect development and metamorphosis are regulated by the coordination of ecdysone and juvenile hormones. Insect microRNAs (miRNAs) also act in insect development and metamorphosis by regulating genes in the ecdysone cascade. Although hundreds of insect miRNAs have been identified, the physiological functions of most remain poorly understood. Here, we report that a conserved insect miRNA, microRNA-281 (miR-281), regulates the ecdysone receptor (EcR), in an isoform-specific manner in the silkworm Bombyx mori...

Transgene-based genetic sexing methods are being developed for insects of agricultural and public health importance. Male-only rearing has long been sought in sericulture because males show superior economic characteristics, such as better fitness, lower food consumption, and higher silk yield. Here we report the establishment of a transgene-based genetic sexing system for the silkworm, Bombyx mori. We developed a construct in which a positive feedback loop regulated by sex-specific alternative splicing leads to high-level expression of the tetracycline-repressible transactivator in females only...

The current identification of microRNAs (miRNAs) in insects is largely dependent on genome sequences. However, the lack of available genome sequences inhibits the identification of miRNAs in various insect species. In this study, we used a miRNA database of the silkworm Bombyx mori as a reference to identify miRNAs in Helicoverpa armigera and Spodoptera litura using deep sequencing and homology analysis. Because all three species belong to the Lepidoptera, the experiment produced reliable results. Our study identified 97 and 91 conserved miRNAs in H...

MucK is a member of the major facilitator super family (MFS) and is within a subgroup involved in the uptake of organic acids. Here, we provide the first evidence that mucK is required for normal body color pattern in insect larvae. In the cts mutant strain of Bombyx mori (Linnaeus), the larval anal plates, prothoracic tergum, and the head are reddish brown, as opposed to the white color found in the wild type. Positional cloning of the cts gene was carried out and it was mapped within 90kb on the 16th chromosome...

The Asian corn borer, Ostrinia furnacalis, is a serious pest of corn, sorghum, and cotton in China and other Asian countries. The present study is the first attempt to establish the transgenic line in O. furnacalis using a piggyBac transposon, which will shed light on the future genetic control of O. furnacalis. A piggyBac vector pBac[A3EGFP] was constructed to express enhanced green fluorescence protein (EGFP)under the control of Bombyx mori actin3 promoter. Transient EGFP expression was detected 48 h after preblastodermic microinjection of pBac[A3EGFP] and the excision assay showed the transgenic vector was precisely excised...