Guangmao Shen

Serine proteases are essential for development and physiology in arthropods. We previously showed that RNAi-mediated silencing of the serine protease gene TcSP3 induces embryonic lethality in the carmine spider mite, Tetranychus cinnabarinus, but the underlying mechanism was unclear. Here, we adopted an integrated strategy—transcriptome sequencing, RT-qPCR validation, and gene-specific RNAi—to pursue two distinct but complementary objectives: (i) to map the downstream transcriptional response to TcSP3 silencing and thereby identify candidate RNAi targets and (ii) to functionally interrogate the leading candidate, TcHKB, in order to infer the lethal mechanism. We additionally performed a preliminary evaluation of the environmental biosafety of the resulting candidate dsTcHKB for RNAi-based mite management. TcSP3 silencing altered 495 genes (464 upregulated and 31 downregulated). Six downregulated candidate genes were validated; among these, silencing TcHKB resulted in the highest egg mortality (53.57%), accompanied by malformation and incomplete development, whereas silencing TcbHLH and Tcngn-1 caused 34.99% and 22.93% mortality. Sequence homology and domain prediction indicate that TcHKB encodes a Sp5-like transcription factor of the Sp/KLF family, suggesting that TcHKB may indirectly affect developmental signaling. The downregulation of TcHKB is therefore proposed as a possible, yet unverified, explanation for the observed embryonic lethality; direct measurements of Sp5, β-catenin, or Wnt pathway activity are still required to confirm this link. For translational application, we also conducted a preliminary biosafety evaluation of dsTcHKB. Under our tested conditions, sequence alignment showed no extensive homology between dsTcHKB and genes of the predatory mite N. barkeri, and direct bioassays detected no adverse effects on its survival, hatchability, or development; the dsRNA additionally degraded almost completely on cowpea leaves within three days. These initial observations address two specific risk aspects—environmental dissipation on cowpea leaves and non-target effects on N. barkeri—but do not yet establish general safety. This study suggests a plausible mechanism for TcSP3/TcHKB-mediated lethality and identifies TcHKB as a candidate RNAi target warranting further biosafety assessment.

Understanding plant-insect interactions can help control the harm of herbivorous pests. According to transcriptome data, transcripts of Solanum lycopersicum responding to feeding by Tuta absoluta were screened for important endopeptidase inhibitors. These genes were annotated as serine-type endopeptidase inhibitors from the potato inhibitor I family, potato type II proteinase inhibitor family, and soybean trypsin inhibitor (Kunitz) family. Based on the analysis of expression patterns, Solyc09g084480.2, Solyc03g020080.2, Solyc03g098760.1, and Solyc01g009020.1 were identified as key genes in the defense system of S. lycopersicum. The major endopeptidase genes such as Tabs008250, Tabs007396, and Tabs005701 in the larval stages of T. absoluta were also detected as potential targets of the plant endopeptidase inhibitors. The interaction mode between these endopeptidase and endopeptidase inhibitors was predicted based on the protein structure construction. This study aims to reveal the molecular response of S. lycopersicum to feeding by T. absoluta with high throughput sequencing and bioinformatics analysis.

Background: Interactions between parasitic insects and their hosts demonstrate the complexity of evolutionary processes. Specifically, the parasitoid wasp Aphidius ervi manipulates its host, the pea aphid Acyrthosiphon pisum, through strategic venom injection to enhance mummification. This study explores how this venom affects the aphid's immune system, particularly targeting the activity of the phenoloxidase (PO) enzyme.Results: Following the injection of venom from A. ervi, significant changes were observed in the expression of immune‐related genes in A. pisum, especially notable expression changes of ApPPOs and a reduction of PO activity. Multi‐omics sequencing identified 74 potential venom proteins in the venom gland of A. ervi, including serine protease homolog 1 (AeSPH1) and serine protease inhibitor (AeSPN1), hypothesized to regulate PO activity. The injection of recombinant protein AeSPH1 and AeSPN1 into the A. pisum hemocoel selectively reduced the expression of ApPPO1, without affecting ApPPO2, and effectively suppressed melanization. Moreover, RNAi targeting AeSPH1 significantly reduced the mummification rate in A. pisum population parasitized by A. ervi.Conclusion: Our findings clarify the complex biochemical mechanisms underlying host‐wasp interactions and highlight potential avenues for developing targeted biological control strategies. © 2024 Society of Chemical Industry.

It has long been disputed whether Tetranychus cinnabarinus and Tetranychus urticae belong to the same genus, with T. cinnabarinus regarded as a red form of T. urticae. However, it is unclear why T. urticae and T. cinnabarinus have different body colors. Since carotenoids are responsible for the color of many organisms, the carotenoid profiles of T. cinnabarinus and T. urticae were compared by HPLC. There was no difference in carotenoid type, but T. cinnabarinus contained significantly more neoxanthin, astaxanthin, α-carotene, β-carotene, and γ-carotene, which may contribute to the deep red color. The transcriptome sequencing of both species identified 4079 differentially expressed genes (DEGs), of which 12 were related to carotenoid metabolism. RNA interference (RNAi) experiments demonstrated that silencing seven of these DEGs resulted in the different accumulation of carotenoid compounds in T. cinnabarinus and T. urticae. In addition, the body of T. urticae turned yellow after two days of feeding with UGT double-stranded RNAs and β-UGT small interfering RNAs. In conclusion, differences in the carotenoid profiles of T. urticae and T. cinnabarinus may be responsible for the different body colors.

BACKGROUND: Global warming is a general trend in the current era. Temperature is one of the most important nonbiological factors that affects the development, life cycle and distribution of arthropods, which are a major component of agriculture pests. This study focused on life‐table parameters and the molecular adaption of Tetranychus cinnabarinus under long‐term thermal stress.RESULTS: The life tables of T. cinnabarinus were constructed at room temperature (26 °C) and high temperature (34 °C). Results showed that although the lifespan of the mites was shortened, the developmental periods of egg, larva and nymph stages were accelerated, and the peak egg‐laying period came earlier at high temperature, which resulted in faster expansion of pest mite population. RNA‐seq was used to reveal the thermal adaption mechanism according to differentially expressed genes. Combined with transcriptome data and quantitative polymerase chain reaction (qPCR) verification, MAPK, CAT, HSP20 and HSP70 were found highly expressed at 34 °C, which were associated with thermal adaption of T. cinnabarinus. RNAi analysis proved that expression of HSP20 was closely related to the survival of mites at high temperature.CONCLUSION: These results indicated that long‐term high temperature treatment was beneficial to the expansion of the T. cinnabarinus population. The genes involved in heat tolerance of T. cinnabarinus such as MAPK‐HSP pathway provides ideas for subsequent control measures. © 2023 Society of Chemical Industry.

In recent years, with the development of the nanomaterials discipline, many new pesticide drug-carrying systems—such as pesticide nano-metal particles, nano-metal oxides, and other drug-carrying materials—had been developed and applied to pesticide formulations. Although these new drug-loading systems are relatively friendly to the environment, the direct exposure of many metal nanoparticles to the environment will inevitably lead to potential effects. In response to these problems, organic nanomaterials have been rapidly developed due to their high-quality biodegradation and biocompatibility. Most of these organic nanomaterials were mainly polysaccharide materials, such as chitosan, carboxymethyl chitosan, sodium alginate, β-cyclodextrin, cellulose, starch, guar gum, etc. Some of these materials could be used to carry inorganic materials to develop a temperature- or pH-sensitive pesticide drug delivery system. Herein, the pesticide drug-carrying system developed based on polysaccharide materials, such as chitosan, was referred to as the pesticide polymer drug-carrying system based on polysaccharide materials. This kind of drug-loading system could be used to protect the pesticide molecules from harsh environments, such as pH, light, temperature, etc., and was used to develop the function of a sustained release, targeted release of pesticides in the intestine of insects, and achieve the goal of precise application, reduction, and efficiency of pesticides. In this review, the recent progress in the field of polysaccharide-based polymer drug delivery systems for pesticides has been discussed, and suggestions for future development were proposed based on the current situation.

Berberine (Ber) is easy to synthesize and has a variety of biological and pharmacological activities. At present, the existing studies on berberine have focused predominantly on its antibacterial activity; its herbicidal activity is rarely reported. In addition, there are a number of preparations of berberine, which are not enough to solve its shortcomings of low solubility and biological activity and the difficult storage of berberine. Here, berberine was combined with carbon dots to obtain carbon dots-berberine (CDs-Ber) nano formulation. The fluorescence quenching results showed that the CDs-Ber nano drug delivery system was successfully constructed, and the fluorescence quenching mechanism of the two was static quenching. The bioassay results showed that CDs had no adverse effects on the growth of barnyard grass (Echinochloa crus-galli) and redroot pigweed (Amaranthus retroflexus), and had high biocompatibility. Berberine and CDs-Ber predominantly affected the root growth of barnyard grass and redroot pigweed and could enhance the growth inhibition effect on weeds, to some extent. The results of the protective enzyme system showed that both berberine and CDs-Ber could increase the activities of Superoxide dismutase (SOD), Peroxidase (POD), and Catalase (CAT) in barnyard grass, and CDs-Ber had a stronger stress effect on barnyard grass than berberine. The determination of the number of bacterial communities in the soil after the berberine and CDs-Ber treatments showed that there was no significant difference in the effects of the two, indicating that CDs-Ber would not have more negative impacts on the environment. The CDs-Ber nano formulation improved the biological activity of berberine, enhanced the herbicidal effect, and was relatively safe for soil colonies.