From genome to proteome: Comprehensive identification of venom toxins from the Chinese funnel-web spider (Macrothelidae: Macrothele yani).

Macrothelidae is a family of mygalomorph spiders containing the extant genera Macrothele and Vacrothele. China is an important center of diversity for Macrothele with 65 % of the known species occurring there. Previous work on Macrothele was able to uncover several important toxin compounds including Raventoxin which may have applications in biomedicine and agricultural chemistry. Despite the importance of Macrothele spiders, high-quality reference genomes are still lacking, which hinders our understanding and application of the toxin compounds. In this study, we assembled the genome of the Macrothele yani to help fill gaps in our understanding of toxin biology in this lineage of spiders to encourage the future study and applications of these compounds. The final assembled genome was 6.79 Gb in total length, had a contig N50 of 21.44 Mb, and scaffold N50 of 156.16 Mb. Hi-C scaffolding assigned 98.19 % of the genome to 46 pseudo-chromosomes with a BUSCO score of 95.7 % for the core eukaryotic gene set. The assembled genome was found to contain 75.62 % repetitive DNA and a total of 39,687 protein-coding genes were annotated making it the spider genome with highest number of genes. Through integrated analysis of venom gland transcriptomics and venom proteomics, a total of 194 venom toxins were identified, including 38 disulfide-rich peptide neurotoxins, among which 12 were ICK knottin peptides. In summary, we present the first high-quality genome assembly at the chromosomal level for any Macrothelidae spider, filling an important gap in our knowledge of these spiders. Such high-quality genomic data will be invaluable as a reference in resolving Araneae spider phylogenies and in screening different spider species for novel compounds applicable to numerous medical and agricultural applications.

Transcriptome sequencing of wolf spider Lycosa sp. (Araneae: Lycosidae) venom glands provides insights into the evolution and diversity of disulfide-rich toxins.

Wolf spiders in the genus Lycosa are important pest predators in agroforestry ecosystems, capable of feeding on a wide range of pests through the use of complex venom which can to quickly immobilize and kill prey. Because of these characteristics the toxins in wolf spiders venom may prove to be natural sources for novel drug development and biopesticides. To better understand the toxins in Lycosa venom we sequenced the transcriptome from venom glands from an undescribed species of Lycosa and comparatively analyzed the data using known protein motifs. A series of 19 disulfide-rich peptide (DRP) toxin sequences were identified and categorized into seven groups based on the number and arrangement of cysteine residues. Notably, we identified three peptide sequences with low identity to any known toxin, which may be toxin peptides specific to this species of Lycosa. In addition, to further understand the evolutionary relationships of disulfide-rich peptide toxins in spider venom, we constructed phylogenetic trees of DRP toxins from three spiders species and found that the Lycosa sp. DRPs are comparatively diverse with previous research results. This study reveals the toxin diversity of wolf spiders (Lycosa sp.) at the transcriptomic level and provides initial insights into the evolution of DRP toxins in spiders, enriching our knowledge of toxin diversity and providing new compounds for functional studies.

Transcriptome-based analyses reveal venom diversity in two araneomorph spiders, Psechrus triangulus and Hippasa lycosina.

The spiders Psechrus triangulus and Hippasa lycosina are widely distributed in Yunnan Province, China, and are important natural enemies of agricultural pests, yet studies regarding the composition of their venom are lacking. In this study, cDNA libraries were constructed from venom gland tissue of P. triangulus and H. lycosina and used for transcriptomic analysis. From the analysis, 39 and 31 toxin-like sequences were predicted for P. triangulus and H. lycosina, respectively. The predicted neurotoxin sequences were categorized according to cysteine sequence motifs, and the predicted neurotoxin sequences of P. triangulus and H. lycosina could be classified into 9 and 6 toxin families, respectively. In addition, potential acetylcholinesterase, hyaluronidase, and astaxanthin-like metalloproteinases were identified through annotation. In summary, transcriptomic techniques were invaluable in mining the gene expression information from these two spider species to explore the toxin composition of their venom and determine how they differ. Studies of this type provide essential baseline data for studying the evolution and physiological activities of spider toxins and for the potential development of medicinal compounds.