生命科学最新文献

RNA silencing and autophagy play crucial roles in maintaining cellular homeostasis and defending against viral infections in diverse eukaryotic hosts. In response to RNA silencing defenses, the majority of plant viruses have evolved viral suppressors of RNA silencing (VSRs). Cassava mosaic geminiviruses (CMGs) are a group of bipartite begomoviruses that cause significant losses to the staple food crop cassava (Manihot esculenta Crantz). The AC4 protein, encoded by CMGs, is a well-characterized VSR; however, the precise mechanism underlying its suppression of RNA silencing remains unclear. This study demonstrates that AC4 expression impedes tasiRNA biogenesis. Moreover, the AC4 protein has been observed to interact with both SGS3 and its partner RDR6, which are essential for the synthesis of trans-acting small interfering RNAs and the amplification of RNA silencing. Notably, these interactions do not disrupt the association between AtSGS3 and AtRDR6 but instead induce their degradation. Furthermore, the AC4-mediated degradation of AtSGS3 is suppressed by an autophagy inhibitor, and AC4 enhances autophagy activity. The results indicate that the autophagy pathway is involved in AC4-mediated degradation of SGS3. These findings reveal a previously unidentified mechanism by which AC4 exploits autophagy to attenuate host RNA silencing, thereby impacting plant development and fulfilling its VSR function. This study offers new insights into the intricate relationship between RNA silencing and autophagy.

Nornicotine content is very low in tobacco, accounting for less than 5% of total alkaloids. Nicotine conversion refers to the process by which nornicotine is synthesised spontaneously and in large quantities from nicotine. CYP82E4 is the only key enzyme gene involved in nicotine conversion, but it is unclear by what mechanism plants regulate the expression of this gene and thus change the phenotype of nicotine conversion. By comparing single-base resolution DNA methylomes of senescent leaves from NC-L and its high converter variant NC-H, we found two differentially methylated regions (DMRs) in CYP82E4 of NC-H. The bisulfite sequencing PCR (BSP) assay demonstrated that the DNA methylation levels in two specific segments of CYP82E4 were 39%-52% lower for NC-H than for NC-L. Furthermore, treatment with the DNA methylase inhibitor 5-azacitidine resulted in a decrease in DNA methylation levels of CYP82E4 and the change of nicotine conversion phenotype from norconverter tobacco to high converter tobacco. Similarly, the MET1 mutation significantly reduced the DNA methylation level of CYP82E4 and transformed the nicotine conversion phenotype. These findings suggest that DNA methylation plays a crucial regulatory role in nicotine conversion, with decreased methylation levels in CYP82E4 being significant factors in nicotine conversion.

Germination represents the first major transition in plants, and seed dormancy influences germination timing. However, the mechanism by which variations in seed dormancy due to genetic variation or the maternal environment influence germination timing has not been studied in depth. In this study, the effects of temperature during seed maturation (maternal temperature) and genetic variation on weedy rice seedling emergence in a field environment were evaluated. The experiments were repeated for 4 years using seeds collected from weedy rice groups, which represented different degrees of seed dormancy. The maternal temperature was evaluated via the yearly variation in the field temperature. Genetic variation had a greater effect on seedling emergence during unfavourable seasons than during favourable seasons. A higher maternal temperature delayed seedling emergence during favourable seasons. The notable impact of global warming on seedling emergence has been confirmed over the past 15 years, and this impact will continue even under the sustainable CO₂ emission scenario. Maternal effects have long-term effects on seedling emergence at relatively high maternal temperatures, and these effects may increase under global warming.

Outside Front Cover: The cover image is based on the article Crucial Role of Aluminium-Regulated Flavonol Glycosides (F2-Type) Biosynthesis in Lateral Root Formation of Camellia sinensis by Sanyan Lai et al., https://doi.org/10.1111/pce.15372.

Terrestrial plants naturally produce chemical signals to attract beneficial insects or repel harmful pests. These inherent plant attributes offer promising opportunities for eco-friendly pest control in agriculture, particularly through the push-pull intercropping technique. However, our understanding of potential repellent plants and their effective chemical signals remains limited. In this study, we evaluated multiple plant species for their repellent properties, identified effective volatile organic compounds, and investigated the mechanisms for controlling the fungus gnat Bradysia odoriphaga in Chinese chives. Among the 12 species tested, Mentha haplocalyx, Ocimum basilicum and Pelargonium graveolens demonstrated strong repellent effects, making them promising candidates as 'push' plants. Eight major volatile compounds were identified as effective repellents, with 1,8-cineole being the most efficient. 1,8-cineole consistently exhibited repellent effects against the fungus gnats across various concentrations and exposure durations. Transcriptomic analysis revealed that exposure to 1,8-cineole upregulated genes is associated with energy production processes, suggesting that the fungus gnats can detect and actively avoid this compound. Field experiments further confirmed the effectiveness of this strategy, as intercropping chives with M. haplocalyx significantly reduced fungus gnat infestations. This study presents a novel intercropping approach for managing fungus gnats and offers valuable insights into sustainable eco-friendly pest management practices in agriculture.

Salt stress can seriously affect plant survival. To adapt to salt stress, plants can alter gene expressions and/or pre-mRNA processing patterns, or both. Previous studies could not comprehensively profile stress-responsive pre-mRNA processing patterns due to limitations in traditional sequencing technologies. Now Oxford Nanopore Technologies Direct RNA Sequencing (ONT DRS) can directly sequence full-length native RNAs without requiring reverse transcription or amplification. Thus, it provides accurate profiles of pre-mRNA processing patterns at the single-molecule level. With this technology, we found more than 89 586 novel transcript isoforms in addition to the 44 877 annotated ones in soybean leaves and roots subjected to short-term salt stress. Specifically, we identified 102 191 alternative mRNA processing events and 1216 fusion transcripts corresponding to 549 genomic regions. Interestingly, genes upregulated in roots due to salt stress had longer poly(A) tail lengths and lower m6A modification ratios than controls, and downregulated genes in roots had shorter poly(A) tails. Also, the m6A modification levels changed with prolonged salt stress. Furthermore, the alteration patterns of m6A modifications under salt stress were correlated with the expressions of two m6A erasers. Our results indicated that the reshaped mRNA traits caused by salt stress could play a role in soybean adaptations.

The presence of toxic heavy metals lead (Pb) and cadmium (Cd) in polluted soil damage crop production and consequently harms human and livestock health. Tartary buckwheat (Fagopyrum tataricum) is a potential model plant for heavy metal phytoremediation because of its valuable characteristics of high heavy metal tolerance and abundant biomass production. Here, we report that the Tartary buckwheat FtMYB46-FtNRAMP3 module enhances plant Pb and Cd tolerance. RNA sequencing analysis showed that Pb treatment specifically induced expression of FtNRAMP3, a member of the NRAMP (Natural Resistance-Associated Macrophage Protein) transporter gene family. Further cytological and biochemical analysis revealed that FtNRAMP3 was localised to the plasma membrane and significantly contributed to increased tolerance to Pb and Cd in yeast cells. Consistently, transgenic overexpression of FtNRAMP3 in Arabidopsis significantly increased plant tolerance to Pb and Cd applications, reducing Pb concentration but increasing Cd concentration in the overexpression transgenic plants. Subsequent yeast one-hybrid and electrophoretic mobility shift assays showed that the transcription factor FtMYB46 directly binds to the FtNRAMP3 promoter. Further, FtMYB46 promoted FtNRAMP3 expression and increased plant Pb and Cd tolerance. Overall, this study demonstrates the important role of the FtMYB46-FtNRAMP3 module and its potential value in the phytoremediation of Pb and Cd stress.

The revival mechanism in dormant bacteria is a puzzling and open issue. We propose a model of information diffusion on a regular grid where agents represent bacteria and their mutual interactions implement quorum sensing. Agents may have different metabolic characteristics corresponding to multiple phenotypes. The intra/inter phenotype cooperation is analyzed under different metabolic and productivity conditions. We study the interactions between rapidly reproducing active bacteria and non-reproducing quiescent bacteria. We highlight the conditions under which the quiescent bacteria may revive. The occurrence of revival is generally related to a change in environmental conditions. Our results support this picture showing that revival can be mediated by the presence of different catalyst bacteria that produce the necessary resources.

The innovative HaloTag is a labeling technology that plays a crucial role in advanced fluorescence imaging. However, due to the complexity of plant materials, the application of HaloTag technology in the field of plants is still in its infancy. To expand the application of HaloTag technology in plant cells, we constructed six eukaryotic gene expression vectors with different localizations carrying HaloTag labels, then transformed Arabidopsis thaliana and Nicotiana benthamiana, and finally stained the living cells using HaloTag ligands. Live-cell imaging showed that HaloTag did not affect the localization pattern and biological functions of the target protein, and by improving the experimental conditions, the optimized HaloTag technology could be more effectively applied to plants. Remarkably, we first displayed that the optimized HaloTag technology exhibits superior labeling performance compared to conventional fluorescent proteins, including photostability, monomer properties, multicolor imaging and spatio-temporal differentiated labeling. More importantly, the combination of HaloTag technology with single-particle tracking reveals the specific dynamics of membrane proteins and the changes in the rearrangement of ER-PM connectivity, providing a powerful tool for analyzing protein dynamics. Taken together, this promising HaloTag technology enriches the labeling toolkit for studying spatiotemporal dynamics and various biological processes.

The smut fungus Sporisorium scitamineum is a major pathogen in sugarcane, causing significant agricultural losses worldwide. However, the molecular mechanisms by which its effectors facilitate infection and evade host immunity remain largely unclear. In this study, we identified the sugarcane vacuolar sorting receptor 1 gene (ScVSR1), whose expression negatively correlate with several putative S. scitamineum effector genes in a co-expression network. Overexpression of ScVSR1 in Arabidopsis thaliana reduced resistance to a fungal powdery mildew pathogen, indicating the negative role of ScVSR1 in plant defence. Among the co-expressed S. scitamineum effectors, SsPE15, a secreted cerato-platanin-like protein (CPP), physically interacts with ScVSR1 and is sorted into the prevacuolar compartment (PVC) by interacting with ScVSR1 in plant cells. Deletion of SsPE15 in S. scitamineum enhanced fungal virulence, suggesting that SsPE15 acts as an immune elicitor. Furthermore, the C-terminal domain of the SsPE15, containing the VSR sorting signal, was found to facilitate vesicular location. Notably, fusing this C-terminal domain to the bacterial effector AvrRpt2 significantly reduced AvrRpt2-triggered programmed cell death in Arabidopsis, a process partially dependent on AtVSR1 and AtVSR2. These findings reveal an immune evasion strategy by which S. scitamineum effector SsPE15 hijacks the host's vesicular trafficking system to avoid immune detection.