Frontiers in Plant Science最新文献

Mitogen-activated protein kinase kinase kinases (MAPKKKs) are central components of the MAPK cascade and play crucial roles in plant growth, development, and stress responses. Nevertheless, the evolutionary dynamics and functional diversification of this gene family within the Asteraceae lineage remain poorly characterized. In this study, we conducted a comprehensive comparative genomic analysis of the MAPKKK family across ten representative Asteraceae species. A total of 1,009 MAPKKK genes were identified and phylogenetically classified into three subfamilies-RAF, MEKK, and ZIK-which were further subdivided into 14 distinct clusters. Structural analysis revealed considerable variation in intron length and gene architecture among subfamilies and species. All Asteraceae MAPKKK genes were grouped into 64 orthologous gene groups (OGGs), including 16 conserved, 28 variable, and 30 rare OGGs. Conserved OGGs comprised 296 genes, accounting for 29.34% of the total MAPKKK genes, and were subject to significantly stronger purifying selection compared with dispensable genes. Chromosomal localization and synteny analyses indicated that whole-genome duplication (WGD) events were the primary drivers of MAPKKK family expansion, with conserved genes retained preferentially under stronger selective constraints than those arising from small-scale duplication (SSD) events. Collinearity analysis further showed that conserved genes constituted over 47.91% of syntenic gene pairs, underscoring their high evolutionary conservation. Promoter analysis identified stress-responsive cis-elements as the most abundant category, representing 41.6% of all detected elements, highlighting the potential role of MAPKKKs in environmental adaptation. Transcriptomic and qRT-PCR assays in sunflower under drought, salt, and alkaline stresses revealed several MAPKKK genes with distinct and stress-specific expression profiles, such as the conserved genes Hann_MAPKKK16 and Hann_MAPKKK135. Together, these results provide important insights into the evolutionary mechanisms governing MAPKKK family expansion and functional specialization, advancing our understanding of stress adaptation in Asteraceae species.

Chromium (Cr) contamination in agricultural soils represents a serious challenge to rice productivity and food security, underscoring the need for innovative approaches to improve Cr-tolerance and alleviate its detrimental effects on plant growth and development. Recently, nanotechnology has been increasingly used to improve the tolerance of plants exposed to metal stress. In view of the beneficial roles of nanoparticles in mitigating metal stress in plants, this study was conducted to assess the effectiveness of cerium dioxide nanoparticles (CeO₂ NPs) in alleviating Cr-induced toxicity in rice plants. Chromium stress (100 µM) and CeO₂ NPs (100 ppm) were applied at the seed stage by soaking the seeds in their respective solutions for 12 h prior to sowing. Chromium stress markedly increased the contents of thiobarbituric acid-reactive substances (TBARS) by 67%, hydrogen peroxide (H₂O₂) by 62%, superoxide anion (O₂•^-) by 58%, and methylglyoxal (MG) by 63% compared with control plants. In contrast, Cr stress significantly reduced the concentrations of starch (51%), sucrose synthase (49%), amylase (68%), chlorophyll (69%), and RuBisCO (67%). However, the application of CeO₂ NPs markedly enhanced plant growth and biomass accumulation, alleviated oxidative stress, and stimulated antioxidant enzyme activities in rice plants subjected to Cr stress. Overall, these results demonstrate that the application of CeO₂ effectively alleviates Cr-induced stress in rice plants and offers promising prospects for advancing NP-based phytoremediation strategies.

Introduction: PSS1 encoding a glycine-rich integral plasma membrane protein plays a pivotal role in nonhost resistance of Arabidopsis against the soybean pathogens, Phytophthora sojae and Fusarium virguliforme. Notably, P. sojae fails to penetrate the wildtype Col-0 ecotype but not the pss1 mutant. To elucidate the molecular basis of PSS1-mediated nonhost immunity, we employed a miniTurbo-based proximity labeling approach.

Methods: The miniTurbo fused to either wild-type PSS1 or its mutant variant, PSS1^G119D, and expressed in the pss1 knockout mutant background. Seedlings were challenged with or without P. sojae zoospores and biotinylated proteins were isolated for mass spectrometry analysis. Col-0 and PSS1^G119D lines served as controls to validate labeling specificity and biological relevance.

Results: Prior to infection, spatial proximity between PSS1 and the plasma membrane H(⁺)-ATPase 6 transporter was detected; however, this association was not observed following P. sojae challenge. Several candidate PSS1-associated proteins were predominantly localized to the plastid and cytosol, suggesting a possible redistribution of PSS1 during infection, potentially to facilitate nonhost immunity. PSS1 is also associated with thioglucoside glucohydrolase 1 (TGG1), a key enzyme in glucosinolate (GLS) metabolism, and to coproporphyrinogen III oxidase (LIN2), involved in tetrapyrrole biosynthesis and reactive oxygen species (ROS) production linked to defense-related cell death.

Conclusions: We hypothesize that PSS1 contributes to a positive feedback loop that enhances multiple defense pathways. Based on consistent enrichment and functional relevance, we nominate TGG1, LIN2, and H(⁺)-ATPase 6 as priority candidates for functional validation in the context of PSS1-mediated nonhost immunity.

Cleome gynandra L. (spider plant) is a traditional leafy vegetable that contains minerals, vitamins, proteins, and phytochemical compounds. However, little is known about the effects of sole KM (kraal manure), GKE (giant kelp extract), and GKE + KM on spider plant leaf mineral composition. This study aimed to determine the effect of sole GKE, KM, and GKE + KM on leaf mineral composition. It is hypothesized that 1 mL/L GKE supplemented with 30 kg/345 m² KM will influence leaf nutrient composition. This hypothesis was tested using a split-plot design across two growing seasons at the University of Fort Hare research farm, to assess treatment-specific effects on macro- and micronutrient accumulation in spider plant leaves. The main plots comprised three levels of KM (0, 30, and 60 kg/345 m²) and subplots comprised five levels of GKE (0, 1, 2, 3, and 4 mL/L), each replicated three times. A two-way analysis of variance test was performed using JMP Pro 18 statistical software package to determine the effects of various levels of GKE and KM application on leaf chemical parameters. Canonical correspondence analysis was performed using R Studio version 4.1.2 (2024). Results showed that application of 30 kg/345 m² KM in season 1 increased (p < 0.05) nitrogen, calcium, magnesium, potassium, sodium, iron, manganese, and zinc. Spider plant treated with 2 mL/L GKE showed increased levels of iron, manganese, and zinc in both summer seasons. Additionally, the combination of 2 mL/L GKE + 30 kg/345 m² KM increased leaf nitrogen, iron, manganese, and zinc. This study confirms that GKE, KM, and GKE + KM play a significant role in leaf mineral uptake.

Introduction: Pests and diseases significantly reduce the quality and yield of corn, while the corn precision pesticide application system is one of the effective measures to solve this problem. However, the detection of corn trumpets in complex farmland environments poses significant challenges due to the high color similarity between corn trumpets and the background, the small target size, and occlusion by corn leaves.

Methods: In this paper, we propose a lightweight HMA-YOLO model to accurately detect corn trumpets in agricultural background based on YOLOv12n model. Firstly, The HCT structure that is based on CNN and Transformer architectures with assignable feature map channels is introduced into the backbone network to extract target feature information and enhance the ability of the model to distinguish between targets and backgrounds. Secondly, an efficient multi-branch and multi-scale feature pyramid network (MBMS-FPN) is developed to enhance the extraction and fusion of deep-level features of targets of varying sizes, which employs the neck heterogeneous kernel selection mechanism and feature weighted fusion module. Finally, an efficient and lightweight asymmetric multi-level channel compression detection head (AMCCDH) is improved to alleviate missed detections caused by occlusion. The AMCCDH improves detection accuracy by deepening the network path of the IoU task branch and expanding its receptive field by using 3×3 depth-wise separable convolutions. Moreover, these three improvement measures all undergo lightweight processing.

Results and discussion: Experimental results show that HMA-YOLO achieves a mAP@0.5 of 91.5%, precision of 89.8%, and recall of 83.7%, operating at 128 FPS with only a model size of 3.1 MB and a parameter count of 1.407M. This model outperforms mainstream object detectors and has been successfully deployed on the NVIDIA Jetson Xavier NX embedded platform, which achieves real-time and efficient detection in resource-constrained environments.

Monomeric compounds from Humulus scandens that effectively inhibit Phytophthora nicotianae were isolated, and their antimicrobial effects were analyzed. Methanol extracts were isolated using a combination of activity tracking and chemical separation methods. Compound structures were identified using NMR and other techniques. Antimicrobial activity against P. nicotianae was assessed via the mycelial growth rate method with mycelial morphology further observed using optical microscopy and scanning electron microscopy. Five compounds were isolated from the ethyl acetate (EtOAc) layer of H. scandens, namely, chromone (compound 1), tectochrysin (compound 2), isorhamnetin (compound 3), hyperoside (compound 4), and Apigenin 7-glucoside (compound 5). All compounds exhibited varying degrees of antimicrobial activity. Compounds 1 and 5 demonstrated superior inhibitory effects, with EC₅₀ values of 51.70 and 31.71 μg/ml and MIC values of 400 and 200 μg/mL, respectively. Microscopic examination revealed that compounds 1 and 5 induced distortion, deformation, shrinkage, collapse, and damage in P. nicotianae mycelia. Additionally, they increased membrane permeability and inhibited mycelial growth by disrupting cellular integrity. This study provides lead compounds for developing green botanical pesticides against tobacco black shank disease and offers data to support green agriculture initiatives.

Salinity and alkaline stress severely restrict rice productivity by disrupting ionic balance, generating oxidative damage, and impairing growth across developmental stages. Despite the significant advances in the salt tolerance knowledge, rice is very sensitive in contrast to other cereals, which demonstrates gaps in mechanistic understanding and breeding efficiency. This review incorporates the progress in the salt perception, signaling, and stress adaptation, and introduces limitations that slow down the practical improvement. Rice senses salinity using receptor-like kinases and Ca²⁺-dependent signaling pathway but the initial stages of the response and down-stream phosphorylation cascades have not been characterized well. The reactive oxygen species (ROS) triggered by salinity activate antioxidant mechanisms like AsA-GSH, but it is still not clear how they are spatially and organelle-specifically controlled. Proteomic analyses show extensive reorganization of proteins in signaling, cytoskeleton dynamics, metabolism and protein turnover, but most of the identified candidates have not been validated functionally. Na⁺ exclusion, vacuolar sequestration, and K⁺ retention through HKTs, NHXs, and V-ATPases are involved in ion homeostasis, but the interactions between them in tissues have not been fully understood yet. QTL studies have also reported important loci like Saltol and qSKC1 but there are slow advances made in using them in elite cultivars. New multi-omics techniques and CRISPR-based genome editing are currently providing a chance to uncover knowledge gaps. All in all, this review presents an overall framework to develop mechanistic knowledge and speed up breeding salt-resistant varieties of rice.

Introduction: The wheat blast fungus Magnaporthe oryzae pathotype Triticum (MoT) poses a severe threat to global wheat (Triticum aestivum L.) production, yet the molecular mechanisms underlying tissue invasion remain poorly understood.

Methods: We performed dual RNA-seq analysis of MoT-inoculated wheat leaves at 0, 24, 36, and 48 hpi, mapping reads separately to the wheat and M. oryzae genomes to capture stage-specific host responses and pathogen gene expression across progressive infection stages.

Results: Wheat exhibited pronounced stage-specific transcriptional reprogramming, with peak differential gene expression at 36 hpi and visible symptoms at 48 hpi. The 24 hpi stage was characterized by rapid induction of immune- and defense-related pathways, including innate immunity and detoxification processes, along with downregulation of cell wall and membrane biosynthesis. By 36 hpi, wheat maintained sustained activation of immune and detoxification pathways, while chloroplast- and photosynthesis-associated genes were broadly repressed, consistent with transcriptional features of metabolic constraint. At 48 hpi, coinciding with lesion initiation, transcriptomes showed persistent, metabolically costly immune and defense responses together with extensive suppression of photosynthesis- and chloroplast-associated functions, which were associated with metabolic strain and a transition toward necrosis. Analysis of pathogen-derived reads revealed temporal induction of multiple effector candidates, including known M. oryzae orthologs and additional effector-like proteins, highlighting coordinated temporal patterns between host immune and metabolic response as well as stage-specific pathogen effector expression.

Discussion: Together, these findings provide a temporal framework for wheat blast susceptibility and highlight key host pathways and effector candidates that define critical windows for functional dissection of MoT virulence and wheat susceptibility.

Introduction: Gastrodia elata Bl. is a medicinal-edible heterotrophic orchid with distinct vertical distribution, but unstable yield and inconsistent quality in cultivation limit its industrial development. The mechanisms by which altitude modulates growth and bioactive compound accumulation in different G. elata forms remain unclear.

Methods: We conducted a two-factor field experiment (two forms: G. elata f. glauca, G. elata f. elata; three altitudes: 650, 1653, 1953 m) in the Qinba Mountains, using a consistent commercial Armillaria sp. strain to isolate bacterial effects. We analyzed microclimate, soil properties, soil enzyme activities, culturable bacterial communities, and tuber bioactive compounds (gastrodin, parishins) across developmental stages.

Results: Form-specific altitudinal responses were observed: total yield peaked at high altitude (1953 m; 2668.11 ± 317.10 g), while bioactive compounds were enriched at middle altitude (1653 m)-with optimal accumulation at the Large Baima stage (f. glauca) and Mima stage (f. elata). Soil pH was the primary correlative factor for f. glauca quality (explaining 52%-70.5% of variation in RDAs), whereas integrated carbon-acquiring enzyme activity (16.6%) was key for f. elata-consistent with PLS-SEM evidence of an indirect "soil properties→enzyme activities" pathway for f. elata quality. Culturable tuber-associated bacteria (dominated by Pseudomonadota, least diverse at middle altitude) correlated divergently with yield and quality: positively with yield but negatively with quality in f. glauca; weakly positive with yield and strongly (non-significantly) positive with quality in f. elata (p < 0.05).

Discussion: Our findings clarify form-specific correlative networks linking altitude, microenvironment, soil microbes, and plant performance, providing targeted guidance for ecological cultivation to balance high yield and quality in G. elata.

Hazelnuts (Corylus avellana L.) are susceptible to aflatoxin contamination, with recurrent notifications reported in Azerbaijan. A three-year study (2023-2025) was conducted in 30 orchards across three main hazelnut-producing districts to investigate the pre-harvest dynamics of Aspergillus section Flavi. Fungal populations were monitored at four phenological stages (BBCH 70-89), and aflatoxin levels were assessed at harvest and late-harvest. Fungal abundance and incidence were significantly affected by geographical area, year, and growth stage (P < 0.01). A. section Flavi populations were higher in warmer districts such as Qabala and Zaqatala (up to 1.7 Log₁₀ CFU/g) compared with Khachmaz (1.0 Log₁₀ CFU/g), with relative incidence reaching 13.8% in Zaqatala. Fungal abundance peaked during nut filling (BBCH 79), reaching 2.4 Log₁₀ CFU/g, with a corresponding incidence of 18.5%. Marked interannual variability was observed, with A. section Flavi incidence increasing from 1.2% in 2023 to 40.8% in 2024. Despite the frequent isolation of A. section Flavi, aflatoxin levels in standard orchard samples collected at BBCH 89 remained generally below EU limits (≤5 μg/kg). In contrast, late-harvest samples showed markedly higher contamination, with total aflatoxin concentrations ranging from 71.2 to 752.8 μg/kg, particularly in ground-collected nuts. These findings indicate that pre-harvest aflatoxin risk is primarily driven by orchard microclimate and harvest timing, highlighting the importance of Good Agricultural Practices, timely harvest, and rapid post-harvest drying.