Contrasting responses of cuticular bacteria of Pardosa pseudoannulata under cadmium stress.

Although research into how spiders respond to cadmium (Cd)-induced toxicity is ongoing, little is known about the effects of Cd contamination on the exogenous microorganisms of spiders. The current study used 16 S rRNA gene sequencing to evaluate the richness and structure of external bacterial communities in the wolf spider Pardosa pseudoannulata under long- and short-term Cd stress. Our results showed that Proteobacteria and Acidibacter were the dominating bacterial phylum and genus. The alpha diversity analysis showed that the high background of Cd concentration (Cd) reduced bacterial alpha diversity, and short-term Cd (SCd) stress elevated bacterial richness and diversity. Hub bacterial genera, including Stenotrophobacter, Hymenobacter, Chitinophaga, and Bryobacter, were identified by co-occurrence network analysis and showed high connectance with other bacterial genera. Further investigation revealed 15 and 14 bacterial taxa that were classified distinctively under SCd and Cd stresses. Interestingly, functional prediction analysis showed that Cd stress enhanced some crucial pathways involved in specialized functions, including manganese oxidation and aromatic compound degradation. Random forest and correlation analyses found that the spider's molting time was the dominant driver affecting bacterial phyla (i.e., Proteobacteria and Planctomycetes) and genera (e.g., Acidibacter, Reyranella, and Haliangium). Collectively, this comprehensive analysis creates new perspectives to investigate the divergent responses of microbial communities in the spiders' external habitat under Cd stress, and provides valuable viewpoints for Cd pollution evaluation and control.

Effects of wild, local, and cultivated tobacco varieties on the performance of Spodoptera litura and its parasitoid Meteorus pulchricornis.

BACKGROUND: Plant domestication can alter plant and insect interactions and influence bottom-up and top-down effects. However, little is known about the effects of wild, local, and cultivated varieties of the same plant species in the same region on herbivores and their parasitoids. Here, six tobacco varieties were selected: wild Bishan and Badan tobaccos, local Liangqiao and Shuangguan sun-cured tobaccos, and cultivated Xiangyan 5 and Cunsanpi. We examined how wild, local, and cultivated tobacco types affect the tobacco cutworm herbivore Spodoptera litura and its parasitoid Meteorus pulchricornis. RESULTS: Levels of nicotine and trypsin protease inhibitor in leaves and the fitness of S. litura larvae varied significantly among the varieties. Wild tobacco had the highest levels of nicotine and trypsin protease inhibitor, which reduced the survival rate and prolonged the development period of S. litura. The tobacco types significantly influenced the life history parameters and host selection of M. pulchricornis. The cocoon weight, cocoon emergence rate, adult longevity, hind tibia length, and offspring fecundity of M. pulchricornis increased, whereas the development period decreased from wild to local to cultivated varieties. The parasitoids were more likely to select wild and local varieties than cultivated varieties. CONCLUSION: Domestication of tobacco resulted in reduced resistance to S. litura in cultivated tobacco. Wild tobacco varieties suppress S. litura populations, adversely affect M. pulchricornis, and may enhance bottom-up and top-down control of S. litura. © 2023 Society of Chemical Industry.

Integrated transcriptome and metabolome analysis reveals molecular responses of spider to single and combined high temperature and drought stress.

High temperature and drought are abiotic stresses restricting many arthropods' survival and growth. Wolf spiders are poikilothermic arthropods that are vital in managing insects and pests. Nonetheless, investigating changes in spiders under temperature and drought stress are limited, especially at the molecular and gene expression levels. The study found that the combined effects of high temperature and drought stress significantly reduced survival rates and raised superoxide dismutase and malondialdehyde levels in the wolf spider Pardosa pseudoannulata. An integrated transcriptome and metabolome analysis showed that differentially expressed genes and metabolites were highly enriched in pathways involved in the proteolysis and oxidation-reduction process. The gene expression profiles displayed that heat shock protein (HSP) families (i.e., small heat shock protein, HSP70, HSP90, and HSP beta protein) were up-regulated under temperature and/or drought stresses. Additionally, a conjoint analysis revealed that under the combined stress, several important enzymes, including maltase-glucoamylase, glycerol-6-phosphate transporter, alanine-glyoxylate transaminase, and prostaglandin-H2 D-isomerase, were altered, affecting the metabolism of starch, sucrose, amino acids, and arachidonic acid. The protein interaction network further confirmed that under the combined stress, metabolic processes, peptide metabolic processes, and ATP generation from ADP were up-regulated, indicating that spiders could accelerate the metabolism of carbohydrates and proteins to combat stress and maintain homeostasis. Overall, this work showed that exposure to a combination of pressures might cause distinct defensive reactions in spiders and offered novel perspectives to research the molecular underpinnings of spider adaptation to a changing climate.

Metabolome analysis reveals the toxic effects of cadmium exposure on the egg sac of spider Pardosa pseudoannulata.

The investigation of the toxic effects of cadmium (Cd) on rice field invertebrates has attracted accumulating attention. Spider grants a novel insight into the impacts of Cd stress on invertebrates, but the effects of Cd-induced toxicity and molecular response mechanism of related metabolites in spider's egg sacs remain elusive. This investigation found that Cd stress distinctively decreased vitellogenin (Vg) content and hatched spiderlings numbers in the egg sac of Pardosa pseudoannulata. In addition, Cd stress exerted oxidative stress in the egg sac, manifested as the increase of superoxide dismutase and malondialdehyde levels. Further results showed that Cd exposure could affect egg sacs' energy metabolism, including protein and lipid contents. Metabolome analysis generated 73 up-regulated and 63 down-regulated differentially expressed metabolites (DEMs), mainly affecting phenylalanine metabolism, alpha-linolenic acid metabolism, pentose phosphate pathway, and biosynthesis of amino acids. Specifically, pathway analysis showed that Cd exposure down-regulated several key factors, including tyrosine, L-phenylalanine, O-phospho-L-serine, and L-cystathionine, and inhibited the metabolism of amino acids in the egg sacs. The subsequent correlation analysis found that three metabolite indicators, 9-Oxo-ODE, PG (17:0/18:2), and PE (17:0/20:5), were the dominant contributors to the egg sec's properties (i.e., Vg content and gained spiderlings). Collectively, this study hopes to provide valuable data for the protection of rice field spiders and offer novel perspectives for Cd pollution assessment and management.

Transcriptomic analysis of cadmium toxicity and molecular response in the spiderling of Pirata subpiraticus.

Cadmium (Cd) is a kind of toxic heavy metal widely distributed in the environment, posing life-threatening challenges to organisms. The paddy field spider is a natural enemy of pests and an essential component of rice biodiversity. Nonetheless, the effects of Cd stress on the postembryonic development of spiders and its detailed mechanism remain to be investigated. In the present study, we found that Cd stress posed adverse impacts on the growth indicators (e.g., carapace length, development duration, and survival rate) and increased the levels of three antioxidants (i.e., superoxide dismutase, glutathione S-transferase, and glutathione peroxidase) in the spiderlings of Pirata subpiraticus. An in-depth transcriptome analysis was employed in the study, and the results displayed that differentially expressed genes (DEGs) involved in postembryonic morphogenesis, development involved in symbiotic interaction, postembryonic development, and growth were distinctively altered under Cd stress. Further enrichment analysis showed that Cd exposure could activate the apoptosis pathway in the spider via the up-regulation of several key factors, including caspase-10, α-tubulin, actin, etc. In addition, we demonstrated that the increased level of glutathione-related enzymes in spiderlings was caused by the activation of glutathione metabolic pathway. The altered hedgehog signaling pathway might affect cell proliferation, tissue patterning, and development of spiderlings. Further protein interaction network displayed that Cd stress could affect multiple biological processes in spiderlings, particularly cellular response to stimulus and system development. To sum up, this study can provide multi-level perspectives to understand the toxicity of Cd on the growth and development of spiders.