Keke Salt Lake is located in the Qaidamu Basin of China. It is a unique magnesium sulfate-subtype hypersaline lake that exhibits a halite domain ecosystem, yet its microbial diversity has remained unstudied. Here, the microbial community structure and diversity was investigated via high-throughput sequencing of the V3–V5 regions of 16S rRNA genes. A high diversity of operational taxonomic units was detected for Bacteria and Archaea (734 and 747, respectively), comprising 21 phyla, 43 classes, and 201 genera of Bacteria and 4 phyla, 4 classes, and 39 genera of Archaea. Salt-saturated samples were dominated by the bacterial genera Bacillus (51.52%–58.35% relative abundance), Lactococcus (9.52%–10.51%), and Oceanobacillus (8.82%–9.88%) within the Firmicutes phylum (74.81%–80.99%), contrasting with other hypersaline lakes. The dominant Archaea belonged to the Halobacteriaceae family, and in particular, the genera (with an abundance of >10% of communities) Halonotius, Halorubellus, Halapricum, Halorubrum, and Natronomonas. Additionally, we report the presence of Nanohaloarchaeota and Woesearchaeota in Qinghai–Tibet Plateau lakes, which has not been previously documented. Total salinity (especially Mg²⁺, Cl^–, Na⁺, and K⁺) mostly correlated with taxonomic distribution across samples. These results expand our understanding of microbial resource utilization within hypersaline lakes and the potential adaptations of dominant microorganisms that allow them to inhabit such environments.

Green mold caused by Penicillium digitatum is one of the most serious postharvest diseases of citrus fruit, and it is ubiquitous in all citrus growing regions in the world. Sterol 14α-demethylase (CYP51) is one of the key enzymes of sterol biosynthesis in the biological kingdom and a prime target of antifungal drugs. Mutations in CYP51s have been found to be correlated with resistance to azole fungicides in many fungal species. To investigate the mechanism of resistance to prochloraz (PRC) in P. digitatum, the PRC sensitivity was determined in vitro in this study to assess the sensitivity of 78 P. digitatum isolates collected in Hubei province. The results showed that 25 isolates were prochloraz-resistant (PRC-R), including six high-resistant (HR) strains, twelve medium-resistant (MR) and seven low-resistant (LR) strains. A sequence analysis showed no consistent point mutations of PdCYP51A in the PRC-R strains, but four substitutions of CYP51B were found, Q309H in LR strains, Y136H and Q309H in HR strains, and G459S and F506I in MR strains, which corresponded to the four sensitivity levels. Based on the sequence alignment analysis and homology modeling followed by the molecular docking of the PdCYP51B protein, the potential correlation between the mutations and PRC resistance is proposed.

Background: Penicillium italicum(blue mold) is one of citrus pathogens causing undesirable citrus fruit decay even at strictly-controlled low temperatures (< 10 °C) during shipping and storage.P. italicumisolates with considerably high resistance to sterol demethylation inhibitor (DMI) fungicides have emerged; however, mechanism(s) underlying such DMI-resistance remains unclear. In contrast to available elucidation on anti-DMI mechanism forP. digitatum(green mold), howP. italicumDMI-resistance develops has not yet been clarified.Results: The present study prepared RNA-sequencing (RNA-seq) libraries for twoP. italicumstrains (highly resistant (Pi-R) versus highly sensitive (Pi-S) to DMI fungicides), with and without prochloraz treatment, to identify prochloraz-responsive genes facilitating DMI-resistance. After 6 h prochloraz-treatment, comparative transcriptome profiling showed more differentially expressed genes (DEGs) in Pi-R than Pi-S. Functional enrichments identified 15 DEGs in the prochloraz-induced Pi-R transcriptome, simultaneously up-regulated inP. italicumresistance. These included ATP-binding cassette (ABC) transporter-encoding genes, major facilitator superfamily (MFS) transporter-encoding genes, ergosterol (ERG) anabolism component genesERG2,ERG6andEGR11(CYP51A), mitogen-activated protein kinase (MAPK) signaling-inducer genesMkk1andHog1, and Ca²⁺/calmodulin-dependent kinase (CaMK) signaling-inducer genesCaMK1andCaMK2. Fragments Per Kilobase per Million mapped reads (FPKM) analysis of Pi-R transcrtiptome showed that prochloraz induced mRNA increase of additional 4 unigenes, including the other twoERG11isoformsCYP51BandCYP51Cand the remaining kinase-encoding genes (i.e.,Bck1andSlt2) required for Slt2-MAPK signaling. The expression patterns of all the 19 prochloraz-responsive genes, obtained in our RNA-seq data sets, have been validated by quantitative real-time PCR (qRT-PCR). These lines of evidence in together draw a general portrait of anti-DMI mechanisms forP. italicumspecies. Intriguingly, some strategies adopted by the present Pi-R were not observed in the previously documented prochloraz-resistantP. digitatumtranscrtiptomes. These included simultaneous induction of all majorEGR11isoforms (CYP51A/B/C), over-expression ofERG2andERG6to modulate ergosterol anabolism, and concurrent mobilization of Slt2-MAPK and CaMK signaling processes to overcome fungicide-induced stresses.Conclusions: The present findings provided transcriptomic evidence onP. italicumDMI-resistance mechanisms and revealed some diversity in anti-DMI strategies betweenP. italicumandP. digitatumspecies, contributing to our knowledge onP. italicumDMI-resistance mechanisms.

A nanoparticle-based fluorescence immunochromatographic test strip (FITS) coupled with a hand-held detector for highly selective and sensitive detection of phosphorylated acetylcholinesterase (AChE), an exposure biomarker of organophosphate (OP) pesticides and nerve agents, is reported. In this approach, OP–AChE adducts were selectively captured by quantum dot-tagged anti-AChE antibodies (Qdot–anti-AChE) and zirconia nanoparticles (ZrO₂ NPs). The sandwich-like immunoreactions were performed among the Qdot–anti-AChE, OP–AChE and ZrO₂ NPs to form a Qdot–anti-AChE–OP–AChE–ZrO₂ complex, which was detected by recording the fluorescence intensity of Qdots captured during the test line. Paraoxon was used as the model OP pesticide. Under optimal conditions, this portable FITS immunosensor demonstrates a highly linear absorption response over the range of 0.01 nM to 10 nM OP–AChE, with a detection limit of 4 pM, coupled with good reproducibility. Moreover, the FITS immunosensor has been validated with OP–AChE spiked human plasma samples. This is the first report on the development of ZrO₂ NP-based FITS for the detection of the OP–AChE adduct. The FITS immunosensor provides a sensitive and low-cost sensing platform for on-site screening/evaluating OP pesticides and nerve agents poisoning.