Background: Predatory mites (Acari: Phytoseiidae) are the most important beneficial arthropods used in augmentative biological pest control of protected crops around the world. However, the genomes of mites are far less well understood than those of insects and the evolutionary relationships among mite and other chelicerate orders are contested, with the enigmatic origin of mites at one of the centres in discussion of the evolution of Arachnida.Results: We here report the 173 Mb nuclear genome (from 51.75 Gb pairs of Illumina reads) of the predatory mite,Neoseiulus cucumeris, a biocontrol agent against pests such as mites and thrips worldwide. We identified nearly 20.6 Mb (~ 11.93% of this genome) of repetitive sequences and annotated 18,735 protein-coding genes (a typical gene 2888 bp in size); the total length of protein-coding genes was about 50.55 Mb (29.2% of this assembly). About 37% (6981) of the genes are unique toN. cucumerisbased on comparison with other arachnid genomes. Our phylogenomic analysis supported the monophyly of Acari, therefore rejecting the biphyletic origin of mites advocated by other studies based on limited gene fragments or few taxa in recent years. Our transcriptomic analyses of different life stages ofN. cucumerisprovide new insights into genes involved in its development. Putative genes involved in vitellogenesis, regulation of oviposition, sex determination, development of legs, signal perception, detoxification and stress-resistance, and innate immune systems are identified.Conclusions: Our genomics and developmental transcriptomics analyses ofN. cucumerisprovide invaluable resources for further research on the development, reproduction, and fitness of this economically important mite in particular and Arachnida in general.

In the post-antibiotic era, the Bacillus-based direct-fed beneficial microorganisms are emerging as a cornerstone for sustainable animal farming. This study aimed to screen and evaluate Bacillus strains with probiotic potential for use as feed additives. A total of 394 Bacillus strains were initially screened based on their extracellular enzyme production (cellulase, protease, and amylase) and antibacterial activities against Escherichia coli, Staphylococcus aureus, and Salmonella enterica. Two strains, Bacillus velezensis FJAT-10508 and FJAT-13563, were selected and subsequently subjected to in vitro probiotic characterization, safety assessment, and whole-genome analysis. The results demonstrated that both strains exhibited α-hemolysis, acceptable antibiotic susceptibility profiles, absence of invasion and cytotoxicity effect on the Caco-2 cells, and no mobile virulence or antibiotic resistance genes, indicating their safety as probiotic candidates. High endospore-forming efficiencies (72.4–90.8%), strong auto-aggregation (74–85%) and co-aggregation abilities (52–82%) were observed. In addition, both strains showed considerable tolerance to simulated gastrointestinal conditions, with vegetative cell and endospore survival rates of 28.33–38.33% and 85–89.67% at pH 2.0, and 38.33–43.33% and 90.33–96.33% in 0.3% bile salts, respectively. Overall, B. velezensis FJAT-10508 and FJAT-13563 demonstrated robust in vitro probiotic properties, supporting their potential application as reliable Bacillus-based feed additives.

The aim of this study was to acquire endospore-former(s) for aquatic animal feed based on the probiotic potential in vitro, including the anti-pathogen spectrum, gastrointestinal fluid tolerance, antioxidant activity, enzyme-producing ability, and basic safety assessment. The strain Bacillus velezensis FJAT-57093 was found to exhibit the strongest antibacterial ability against Aeromonas hydrophila in the agar well diffusion inhibition assays from 111 Bacillus-like strains. Moreover, the results showed that the compounds of the strain FJAT-57093 enriched by acid precipitation might be the main antibacterial metabolites. The strain FJAT-57093 also exhibited antibacterial effects against the aquatic pathogens Photobacterium damselae, Edwardsiella tarda, Vibrio parahaemolyticus, and Vibrio vulnificus. The safety assessment revealed that the strain FJAT-57093 was non-hemolytic and susceptible to ten antibiotics. The putative virulence and antibiotic resistance genes predicted were predominantly intrinsic to the FJAT-57093 genome. Furthermore, the strain FJAT-57093 demonstrated a tolerance of acid and bile salt under the simulated gastrointestinal tract conditions, extracellular enzyme-producing abilities, as well as an auto-aggregation rate of 45.88% at 24 h and co-aggregation rates with the aforementioned five aquatic pathogens, ranging from 14.87% to 58.55%. Additionally, its extracellular metabolites displayed strong antioxidant activities, with ABTS⁺ and DPPH radical scavenging rates of up to 99.82% and 42.74%, respectively. In summary, the strain B. velezensis FJAT-57093 was found to possess strong antibacterial activities against multiple aquatic pathogens and desirable in vitro probiotic properties.

Pseudostellaria heterophylla is one of the Chinese herbal medicines with high medicinal and economic values. From 2019 to 2021, postharvest green mold disease was observed with an incidence of 2~5%...