Understanding how plants regulate water loss is important for improving crop productivity. Tight control of stomatal opening and closing is essential for the uptake of CO2 while mitigating water vapor loss. The opening of stomata is regulated in part by homotypic vacuole fusion, which is mediated by conserved homotypic vacuole protein sorting (HOPS) and vacuolar SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptors) complexes. HOPS tethers apposing vacuole membranes and promotes the formation of trans-SNARE complexes to mediate fusion. In yeast, HOPS dissociates from the assembled SNARE complex to complete vacuole fusion, but little is known about this process in plants. HOPS-specific subunits VACUOLE PROTEIN SORTING39 (VPS39) and VPS41 are required for homotypic plant vacuole fusion, and a computational model predicted that post-translational modifications of HOPS may be needed for plant stomatal vacuole fusion. Here, we characterized a viable T-DNA insertion allele of VPS39 which demonstrated a critical role of VPS39 in stomatal vacuole fusion. We found that VPS39 has increased levels of phosphorylation at S413 when stomata are closed versus open, and that VPS39 function in stomata and embryonic development requires dynamic changes in phosphorylation. Among all HOPS and vacuolar SNARE subunits, only VPS39 showed differential levels of phosphorylation between open and closed stomata. Moreover, regions containing S413 are not conserved between plants and other organisms, suggesting plant-specific mechanisms. Our data are consistent with VPS39 phosphorylation altering vacuole dynamics in response to environmental cues, similar to well-established phosphorylation cascades that regulate ion transport during stomatal opening.
Nitrogen (N) is an essential macronutrient for plant growth and yield, yet optimizing nitrogen use efficiency remains a challenge in agriculture. To better understand the regulatory basis of plant responses to N availability, we constructed a maize-specific nitrogen uptake efficiency gene regulatory network (mNUEGRN) comprising 1625 protein–DNA interactions (PDI) between 70 promoters and 301 transcription factors using enhanced yeast one-hybrid assays. We also projected a sorghum NUE GRN (spNUEGRN) based on maize orthologs and analyzed N-responsive subnetworks in both species using transcriptome profiling under N stress of early deprivation and recovery. Cross-species comparison with an existing Arabidopsis GRN revealed about 18% conserved interaction, corresponding to 11% of the mNUEGRN, particularly within the nitrate assimilation pathways. Notably, bZIP18 and bZIP30 emerged as central regulators in mNUEGRN, forming highly connected feed-forward loops (FFLs). From our time series data, we identified 19 236 and 23 864 differentially expressed genes in maize and sorghum, respectively. Gini correlation analysis uncovered 764 and 638 FFLs in mNUEGRN and spNUEGRN, respectively, of which 22 FFLs in maize and 35 in sorghum were identified in both leaf and root for each species. These FFLs may represent candidate regulatory motifs that contribute to modulating transcriptional responses under fluctuating N conditions, but their potential roles require further investigation. Together, our findings reveal evolutionarily conserved and species-specific regulatory strategies that mediate early N responsiveness, offering a foundation for engineering crops with improved NUE.
The evolutionary mechanisms underlying ecological divergence between closely related species remain a central question in biology. Scirpus mariqueter is a coastal halophyte thriving in the saline intertidal zone and exhibits marked adaptive differences compared to its freshwater relative Bolboschoenus planiculmis. However, the genomic and physiological bases of its salt tolerance remain poorly understood. We generated high-quality genome assemblies for both species and investigated the anatomical and physiological innovations underpinning S. mariqueter's adaptation to extreme environments. Morphological analyses revealed that S. mariqueter evolved specialized traits—including denser leaf palisade tissues, enhanced stem aerenchyma, and compact root cortices—synergistically limiting salt intrusion. Using chromosome-level genomes, we identified lineage-specific expansions in S. mariqueter of gene families critical for salinity tolerance, including those regulating carbohydrate metabolism, photosynthetic fidelity, and reactive oxygen species (ROS) detoxification. Strikingly, germin-like protein (GLP) and wound-induced protein (WIP) families contain tandem repeats mediating ROS scavenging and cell wall integrity, underwent adaptive expansion, paralleling anatomical innovations. Physiological profiling under salt stress confirmed S. mariqueter's unique capacity to maintain photosynthetic activity and carbohydrate production, directly linking genomic adaptations to functional resilience. This study reveals an adaptive strategy whereby structural modifications, diversification of stress-responsive gene families, and metabolic stability collectively enable S. mariqueter to thrive in saline ecosystems.
Eucalyptus, one of the most widely planted plantation tree species globally, is primarily found in tropical and subtropical regions and contributes significantly to economic and social benefits. With advances in sequencing technologies, there is an increasing demand for the systematic analysis of multi-omics data among Eucalyptus species to enhance genetic breeding efforts. Although several early genomic databases have been established for eucalyptus, they have not been updated in a timely manner and lack recent multi-omics data, rendering them insufficient for current research needs. To address this gap, we developed the eucalyptus multi-omics database (EucaMOD, http://eucalyptusggd.net/eucamod), a comprehensive resource for cross-omics studies. In this study, we functionally annotated 45 eucalyptus genomes and structurally annotated 15, conducting comparative genomics and pan-proteomics analyses across all genomes. Additionally, we analyzed eucalyptus transcriptome, epigenome, and variome data through standardized workflows, enabling the in-depth mining and reanalysis of multi-omics datasets. EucaMOD is the most comprehensive multi-omics database for eucalyptus to date and includes data from 45 genomes (39 species), 870 mRNA-seq samples, 17 miRNA-seq samples, 52 epigenomic datasets (histone modifications and transcription factor binding), and genetic variation data from 1219 samples. To support functional genomics and molecular breeding research, the database is organized into the following 11 modules: Home, Species, Genomics, Comparative genomics, Pan-proteomics, Transcriptomics, Epigenetics, Variomics, Tools, Download, and Help. EucaMOD also offers online analysis tools for data mining, providing free public services to aid eucalyptus gene function and genetic engineering studies.
Post-harvest loss of fruits and vegetables poses significant challenges to food security and economic sustainability, primarily due to ripening-associated excessive softening that shortens shelf life and increases susceptibility to pathogens. N-glycans, N-glycoproteins, and their processing enzymes are integral to various plant processes, including fruit ripening. Among these, α-D-mannosidase (α-Man) and β-D-N-acetylhexosaminidase (β-Hex) are key ripening-specific enzymes that modulate fruit softening. Previously, we have shown that RNAi-mediated suppression of α-Man or β-Hex improves fruit shelf life and firmness in both climacteric and non-climacteric fruits. However, the underlying molecular and biochemical basis of fruit softening regulation by α-Man and β-Hex was not well understood. In this study, we developed transgenic tomato (Solanum lycopersicum) plants by silencing α-Man and β-Hex simultaneously using RNAi. Suppression of these enzymes reduces N-glycoprotein degradation, downregulates pectin dissolution, and inhibits ripening-related gene expression. RNAi fruits exhibited enhanced shelf life, greater firmness, reduced reactive oxygen species (ROS) accumulation and increased resistance against post-harvest pathogens without affecting plant growth, fruit development, yield, or nutritional quality. To further explore the molecular mechanism of α-Man and β-Hex function, we purified and quantified N-glycans in RNAi fruits and other ripening-impaired mutants, identifying key N-glycan species. We also carried out iTRAQ-based quantitative proteome profiling to investigate the abundance of proteins in ripened fruit affected by silencing of α-Man and β-Hex. Molecular insights revealed that N-glycan processing and degradation are key events during ripening, influencing cell wall softening, fruit redox state, and post-harvest quality attributes. This study highlights the potential of co-silencing α-Man and β-Hex as a novel approach to extending the shelf life of fruits, regardless of their climacteric behavior, without compromising quality or yield.
Artemisia argyi, a perennial herb of the Asteraceae family, possesses significant therapeutic and economic value. We present a 7.88 Gb chromosome-level haplotype-resolved genome assembly, revealing its unique evolutionary trajectory. The karyotype (2n = 34) of A. argyi is that of an autotetraploid, which underwent gametic chromosome fusion prior to species-specific whole-genome duplication (WGD-3). The genome exhibits pronounced multivalent chromosome pairing and frequent recombination among homologous groups. Asymmetrical evolution following WGD-3 is a hallmark feature, evidenced by imbalanced allelic gene loss and widespread neofunctionalization. The terpene synthase (TPS) gene family exemplifies this pattern, having expanded through four duplication events in A. argyi. Recent tandem duplications and allelic functional differentiation have generated substantial gene functional diversity. Notably, we identified a tandem-duplicated six-copy ADS homolog (AarADS)—a key TPS gene in the artemisinin biosynthetic pathway of Artemisia annua (AanADS)—localized exclusively to a single chromosome in A. argyi. Unlike AanADS, which converts farnesyl pyrophosphate (FPP) to amorpha-4,11-diene, AarADS catalyzes FPP to α-bisabolol. Evolutionary analysis suggested that AanADS acquired its specialized function via a derived mutation in the A. annua lineage. This study elucidates the genomic evolution underpinning A. argyi's distinctive medicinal properties.
C4 photosynthesis alleviates the limitation caused by the oxygenase activity of Rubisco by partitioning photosynthetic functions between two distinct cell types: bundle sheath cells (BSCs) and mesophyll cells (MCs). These cell types perform different steps of photosynthesis using specialized machinery, accompanied by differential expression of chloroplast genes. To uncover the underlying molecular mechanisms for this differentiation, we isolated BSCs and MCs and compared their chloroplast transcriptomes, focusing on the chloroplast NADH dehydrogenase-like (NDH) complex, which is enriched in BSCs. To investigate whether RNA stabilization contributes to differential gene expression, we analyzed RNA footprints that reflect the binding of pentatricopeptide repeat (PPR) proteins to their RNA targets. We could not detect cell-type-specific accumulation of footprint RNAs. We then focused on transcriptional regulation, specifically on an operon that starts with the rps15 gene. The operon includes six ndh genes and the psaC gene encoding a photosystem I subunit. Transcript levels of all genes in this operon were higher in BSCs than in MCs, suggesting coordinated regulation as a transcriptional unit. Based on the genomic location of the rps15 gene within inverted repeats near the junctions on both sides of the small single copy region, we demonstrated that rps15, through two distinct promoters, is sufficient to drive preferential accumulation of downstream transcripts in BSCs.
Fruit ripening is regulated by a complex regulatory network, including internal factors and epigenetic modification. Until now, the role of histone methylation in grape fruit ripening is unclear, especially for H3K4me3 modification. H2O2 treatment promotes the ripening of grape berries, but how it regulates fruit ripening and whether it affects H3K4me3 modification is poorly understood. Here, to study the relationship between H2O2 and H3K4me3 modification in fruit ripening, a comprehensive analysis of anti-H3K4me3 ChIP-seq and RNA-seq of grape berries after H2O2 treatment was performed. The results revealed that H2O2 treatment led to changes in expression patterns and H3K4me3 modification in heat shock protein 18.2 (VvHSP18.2), ethylene-responsive transcription factor 75 (VvERF75), and E3 ubiquitin-protein ligase PUB23 (VvPUB23). Overexpression of VvHSP18.2 promoted grape fruit ripening. Among them, VvHSP18.2 positively regulates grape fruit ripening. The potential histone H3K4 demethyltransferase (lysine-specific demethylase JMJ14) with reduced expression after H2O2 treatment was further identified. VvJMJ14 is located in the cytoplasm and negatively regulates grape fruit ripening. VvJMJ14 does not directly interact with VvHSP18.2, VvERF75, and VvPUB23, but promotes their transcription by affecting the H3K4me3 levels in their promoter region after H2O2 treatment. Overall, these results demonstrate that VvJMJ14 is a H3K4 demethyltransferase that promotes the expression of VvHSP18.2, VvERF75, and VvPUB23 by regulating H3K4me3 levels, thereby accelerating H2O2-induced fruit ripening in grape. This study provides a reference for the study of H2O2 regulation of fruit ripening at the epigenetic regulation level.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：