Science China Life Sciences最新文献

Plants have developed fine-tuned cellular mechanisms to respond to intracellular and extracellular signals, which are crucial for their development and adaptation to the ever-changing environment. These cellular responses are often mediated by the highly dynamic cytoskeletal network, including actin filaments and microtubules in plant cells. The cytoskeleton quickly rearranges its organization, through dynamic disassembly and assembly, in response to intrinsic and extrinsic stimuli, which further impacts a variety of cellular activities. In this review, we summarized the roles and regulatory mechanisms of the cytoskeleton in cell morphogenesis, organogenesis, and plant environmental adaptation. We next discussed the relationship between the cytoskeleton and the upstream signals, as well as the research on the cytoskeleton and its relevance in agriculture. Finally, we highlight the key questions remaining to be investigated and put forward some future perspectives in the field.

Germ granules are biomolecular condensates composed of RNA and proteins that play crucial roles in RNA metabolism and post-transcriptional gene regulation. C. elegans germ granules consist of multiple distinct subcompartments, including P granules, Mutator foci, Z granules, SIMR foci, P-bodies, D granules, and E granules. Among these condensates, the E granule, which is nonrandomly positioned within the germ granule, is required for the production of a specialized class of small interfering RNAs (siRNAs). However, the mechanisms underlying E granule formation and its functional significance remain largely unexplored. In this study, via the use of TurboID-based proximity labeling technology combined with an RNAi-based reverse genetic screen, we identified two novel components of the E granule, EGC-2/C27B7.5 and EGC-3/F59G1.8, which initiate E granule assembly. The depletion of EGC-2 or EGC-3 disrupts the perinuclear localization of the EGO and PICS complexes, both of which are enriched in E granules and are required for E-class siRNA and piRNA biogenesis, respectively. Small RNAomic analyses revealed that both EGC-2 and EGC-3 promote the production of 5' E-class siRNA, whereas piRNA accumulation is inhibited by EGC-3. Taken together, our results elucidate the roles of EGC-2 and EGC-3 in maintaining E granule integrity and small RNA homeostasis. Additionally, the combination of proximity labeling technology and reverse genetic screening provides a robust strategy for studying the assembly of biomolecular condensates.

Feed efficiency is a critical economic trait that influences the productivity, profitability, and sustainability of the livestock industry. The gut microbiota plays a significant role in enhancing intestinal health through various mechanisms, including morphology development, immune responses, dietary nutrient digestion and absorption, and host energy metabolism. These processes ultimately promote animal body weight gain and feed efficiency. Over the past few decades, increasing evidence has underscored the importance of gut microorganisms and their metabolites in animal feed efficiency. However, the mechanisms underlying microbial contribution to this trait remain poorly understood, thereby hindering the development of microbial strategies to enhance animal production efficiency. In this review, we focus on the current research findings related to feed efficiency-associated microbiota in the domestic animals that are most commonly used for human food production. We also discuss the potential molecular mechanisms through which the gut microbiome and postbiotics contribute to feed efficiency, aiming to provide novel insights into future research directions on animal gut microbiome and the development of feasible microbial products to improve feed efficiency in the livestock industry.

The mammalian species on the Tibetan Plateau are diverse and abundant, yet our understanding of their gut microbiome and antibiotic resistome remains limited. Here, we used metagenomics to analyse the gut microbiota of 2,561 mammals from the Tibetan Plateau, covering 14 species across six orders. Using de novo metagenome assembly, we reconstructed a total of 112,313 high- to medium-quality metagenomic assembly genomes (MAGs), representing 21,902 microbial species, 86% of which were unclassified. More than 8,000 nonredundant antibiotic resistance genes (ARGs) encompassing 28 types were identified in the gut microbiome of Tibetan Plateau mammals. We further conducted a risk assessment of these ARGs, identifying 334 nonredundant ARGs with high-risk characteristics related to human health. Importantly, seven cross-species horizontal gene transfer events involving high-risk ARGs were identified, three of which occurred between human and nonhuman mammalian gut microbiota. Additionally, we found that the abundance of ARGs in human gut microbiomes on the Tibetan Plateau was greater than that in those from eastern China, Europe, and the United States, whereas the abundance of ARGs in livestock gut microbiomes from the Tibetan Plateau was lower than that in livestock gut microbiomes from those regions. This study reveals that the gut microbiota of Tibetan Plateau mammals is a largely unexplored resource and a significant reservoir of ARGs, offering crucial insights into microbiome research and demonstrating potential public health implications.

Porcine deltacoronavirus (PDCoV) exploits both human aminopeptidase N (hAPN) and porcine APN (pAPN) as receptors, with a higher affinity for hAPN than for pAPN through conserved interaction sites. However, despite this affinity, PDCoV is rarely pathogenic to humans, suggesting that the utilization dynamics of APN homologs by PDCoV are distinct, which is crucial in cross-species transmission but poorly understood. Here, we employed single-virus tracking to visualize and dissect the entry dynamics of PDCoV facilitated by APN. It was discovered that APN homologs bind PDCoV simultaneously, yet the times required for the initiation of membrane fusion and internalization differ significantly. Although high-affinity hAPN, rather than low-affinity pAPN, accompanies PDCoV during internalization, low-affinity pAPN initiates PDCoV internalization approximately 20 s faster than high-affinity hAPN, with caveolae-mediated endocytosis being more predominant and productive. Depending on the cell species, low-affinity pAPN induced a 5% to 25% greater proportion and a 0.6 to 4.3 min faster cell surface fusion, contributing to efficient infection. In contrast, high-affinity hAPN resulted in a 5% to 25% greater proportion and a 5 to 15 min faster endosomal fusion, potentially promoting immune evasion. We further demonstrated that the binding affinities between the PDCoV receptor-binding domain (RBD) and APN homologs are key determinants of the differential kinetics, driving flexible transitions between the two fusion pathways. This receptor affinity-selective PDCoV entry kinetics evolves an optimal balance of immune evasion and rapid infection, underscoring the potential for PDCoV interspecies transmission and the need for its vigilant surveillance.