Plant, Cell & Environment最新文献

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.

Fungal endophytes can alter plant resistance against herbivores by indirectly influencing plant secondary metabolism or through direct effects of their own metabolism. However, the role of fungal endophytes in conifer defences to insect herbivores remains largely unknown. We characterised the endophytic fungal communities and terpene concentrations of 30 white spruce families across two sites. We determined the effects of fungal endophytes on a defoliating insect, eastern spruce budworm, by testing the budworm responses to media amended with fungal endophytes or exposing them to their volatile organic compounds. We further examined whether the changes in the endophytic fungal communities and abundance alter the terpene concentrations of white spruce by inoculating seedlings with endophytic fungi. Terpene and fungal community compositions in mature trees varied among families and sites. The bioassays showed fungal endophytes can kill budworms or reduce their fitness due to the toxicity of fungal mycelium or volatile compounds. The inoculation experiments demonstrated that the changes in fungal communities and abundance can alter the terpene concentrations in seedlings. We developed a "Plant Partnership Hypothesis" to reflect the role of fungal endophytes in plant resistance to insect herbivores, demonstrating a co-evolutionary relationship among fungal endophytes, tree defences, and insect herbivores.

Herbivore elicitors, most of which identified thus far are from the oral secretions (OS) of herbivores, are important in herbivore-induced plant defense. However, whether and how larval OS of the striped stem borer (SSB), Chilo suppressalis, a devastating pest on rice, induce plant defenses remains largely unknown. We found that treating plants with SSB OS enhanced levels of phosphorylated OsMPK3/4/6, JA, JA-Ile, ethylene, and ABA in rice, which subsequently induced the production of defense compounds, such as trypsin protease inhibitors, and decreased the growth of SSB larvae. Digestion by proteinase K decreased the induction activity of SSB OS on rice defense, but it still activated OsMPK6, JA, ABA, and ethylene pathways, and enhanced plant SSB resistance. Treating plants with SSB OS fractions that did not contain fatty acid-amino acid conjugates (FACs) activated OsMPK3/4/6, JA, ABA, and ethylene pathways, whereas treating plants with other OS fractions containing FACs did not. Bioassays revealed that impairing the JA or ABA signaling pathway in rice decreased plant SSB resistance. These results demonstrate that both proteins/peptides and non-proteins/peptides-but not FACs-in SSB OS play a central role in inducing rice defenses by activating signaling pathways mediated by JA, ABA, and ethylene.

Drought is a critical risk factor that impacts rice growth and yields. Previous studies have focused on the regulatory roles of individual transcription factors in response to drought stress. However, there is limited understanding of multi-factor stresses gene regulatory networks and their mechanisms of action. In this study, we utilised data from the JASPAR database to compile a comprehensive dataset of transcription factors and their binding sites in rice, Arabidopsis, and barley genomes. We employed the PyTorch framework for machine learning to develop a nine-layer convolutional deep neural network TFBind. Subsequently, we obtained rice RNA-seq and ATAC-seq data related to abiotic stress from the public database. Utilising integrative analysis of WGCNA and ATAC-seq, we effectively identified transcription factors associated with open chromatin regions in response to drought. Interestingly, only 81% of the transcription factors directly bound to the opened genes by testing with TFBind model. By this approach we identified 15 drought-responsive transcription factors corresponding to open chromatin regions of targets, which enriched in the terms related to protein transport, protein allocation, nitrogen compound transport. This approach provides a valuable tool for predicting TF-TAG-opened modules during biological processes.

As the most prevalent RNA modification in eukaryotes, N⁶-methyladenosine (m⁶A) plays a crucial role in regulating various biological processes in plants, including embryonic development and flowering. However, the function of m⁶A RNA methyltransferase in moso bamboo remains poorly understood. In this study, we identified two m⁶A methyltransferases in moso bamboo, PheMTA1 and PheMTA2. Overexpression of PheMTA1 and PheMTA2 significantly promoted root development and enhanced salt tolerance in rice. Using the HyperTRIBE method, we fused PheMTA1 and PheMTA2 with ADARcd^E488Q and introduced them into rice. RNA sequencing (RNA-seq) of the overexpressing rice identified the target RNAs bound by PheMTA1 and PheMTA2. PheMTA1 and PheMTA2 bind to OsATM3 and OsSF3B1, which were involved in the development of root and salt resistance. Finally, we revealed the effects of transcription or alternative splicing on resistance-related genes like OsRS33, OsPRR73, OsAPX2 and OsHAP2E, which are associated with the observed phenotype. In conclusion, our study demonstrates that the m⁶A methyltransferases PheMTA1 and PheMTA2 from moso bamboo are involved in root development and enhance plant resistance to salt stress.

Plants have evolved the ability to respond to a diverse range of biotic and abiotic stresses. Often, combining these stresses multiplies the challenge for the plants, but occasionally the combined stress can induce unexpected synergistic defences. In maize, combined flooding and herbivory induces a salicylic acid (SA)-dependent defence against Spodoptera frugiperda (fall armyworm). In this study we used RNAseq and metabolic profiling to show that flavonoids are involved in maize response to combined flooding and herbivory. To assess the role of flavonoids in flood-induced S. frugiperda resistance, we analyzed the maize idf mutant that has compromised expression of chalcone synthase, the first enzyme in flavonoid biosynthesis. This flavonoid-deficient mutant was compromised both in flood-induced S. frugiperda resistance and in SA accumulation. These data revealed an unexpected requirement for flavonoids in SA induction. In contrast to idf, the flavonoid 3' hydroxylase mutant, pr1, showed enhanced SA accumulation after combinatorial treatment, which closely correlated with elevated levels of select flavonoids and the dihydroflavonol reductase, anthocyaninless1 (a1) mutant, was unaffected in its SA-induction. These data indicate that specific flavonoids likely play a role in flood-induced SA accumulation and S. frugiperda resistance.

Salt stress is a major abiotic stress restrict plant growth and distribution. In our previous study, we found the ABI5-BINDING PROTEIN 2a (PagAFP2a) gene was rapidly and significantly induced by salt stress in hybrid poplar (Populus alba × Populus glandulosa), however, its function in salt stress responses was unclear. In this study, we further demonstrated that the PagAFP2a gene expression is significantly induced by salt and ABA treatments. Additionally, the ABA-responsive element (ABRE) binding proteins (PagAREB1s) directly bind to PagAFP2a promoter and activate its expression. Physiological analysis showed that PagAFP2a overexpression (PagAFP2aOE) or PagAREB1-3 knockout (PagAREB1-3KO) significantly reduced salt tolerance whereas PagAFP2a knockout (PagAFP2aKO) or PagAREB1-3 overexpression (PagAREB1-3OE) significantly enhanced salt tolerance in poplar. Correspondingly, salt stress responsive genes were significantly upregulated in PagAFP2aKO and PagAREB1-3OE plants while downregulated in PagAFP2aOE and PagAREB1-3KO plants. Furthermore, we demonstrated that PagAFP2a directly interacts with PagAREB1s and represses its transcriptional activity at the target genes. In summary, our results unveil the PagAFP2a-PagAREB1s module form a negative feedback loop in ABA signaling to fine-tune salt stress responses in Populus.

Soil salinity severely restricts crop quality and yields. Plants have developed various strategies to alleviate salinity stress's negative effects, including polyamine redistribution by polyamine uptake transporters (PUTs). However, the mechanisms by which PUTs alter polyamine translocation processes during salt stress have not been fully elucidated. Here, we show that disruption of PUT2, which is involved in polyamine shoot-to-root transport, results in salt sensitivity phenotypes in tomato. Moreover, yeast one-hybrid screened for an HD-Zip transcription factor HB52 that interacts with PUT2, and loss of function of HB52 also led to increased sensitivity to salt stress, whereas HB52-overexpression lines exhibited improved salt tolerance. Furthermore, molecular analyses demonstrated that HB52 directly activated the expression of PUT2 and facilitated Na⁺ efflux by promoting polyamine shoot-to-root mobility. This study uncovers a synergistic transcriptional regulatory network associated with a homeobox protein regulator that promotes polyamine long-distance transport under salt stress.