BACKGROUND AND AIMS:Plant elicitor peptides (Peps), which originate from their precursor proteins known as PROPEPs, play essential roles as signaling molecules that modulate both plant defense responses and developmental processes. METHODS:In this study, we investigated the role of PROPEP2 and its derived peptide Pep2, in regulating root hair development in Arabidopsis thaliana. Root hairs at different growth stages along the primary root and in distinct zones of the root tip were analyzed. We further examined the relationship between Pep2 and auxin signaling in regulating root hair growth. KEY RESULTS:Our findings indicate that loss of PROPEP2 function results in markedly decreased root hair number and elongation during the primary root development phase, whereas root hair formation during the embryonic root stage remains unaffected. Notably, exogenous Pep2 application rescued these defects and even induced root hair formation in non-hair-forming regions. We further demonstrated that Pep2 enhances root hair growth by stimulating localized auxin production in the root tip region. The mutants defective in auxin production (yuc1 yuc4 and wei8 tar1 tar2) failed to respond to Pep2. Furthermore, we identified the receptor-like kinases FERONIA (FER) and [Ca2+]cyt-associated protein kinase 1 (CAP1) as critical components of the Pep2 signaling pathway, with mutations in these genes impairing root hair growth and rendering plants unresponsive to Pep2. CONCLUSIONS:These results uncover a previously uncharacterized interaction between Pep2 and auxin signaling components in the regulation of root hair development, offering additional insights into the molecular control of root morphology.

Toxic Cd (cadmium) pollution in agricultural soil has been drawing global attention. Using exogenous regulators to detoxify Cd in crops is a promising approach to alleviate Cd stress and prevent Cd accumulation in human bodies through the food chain. Natural compounds show great potential due to their environmentally friendly properties. We have found that thymol (a plant-derived natural compound) protects plants from Cd stress. To extend the application of thymol in agriculture, further studies are needed to understand the detailed mechanism by which thymol induces Cd tolerance and limits Cd accumulation in crops. In this study, hydroponic experiments using the roots of Brassica rapa L. exposed to a nutrient solution containing Cd (3 & micro;M) and thymol (15 & micro;M) were conducted to investigate the mechanism of thymol-induced Cd tolerance. Pot experiments with different vegetables (B. rapa, water spinach, and pepper) growing in Cd-polluted soil (0.5 & micro;M Cd) were carried out to investigate the role of foliar spraying of thymol (15 & micro;M) in decreasing the Cd content in vegetables. In the hydroponic study, thymol enhanced the shoot fresh weight and root fresh weight of B. rapa by 313% and 125%, respectively, upon Cd exposure. Thymol detoxifies Cd-induced ROS accumulation by increasing the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in B. rapa by 8.9-33.6%, 12.9-31.6%, and 57.8-135%, respectively. The thymol-activated AsA-GSH (ascorbic acid-glutathione) cycle also contributed to the decrease in ROS level. Thymol also reduced the Cd content in the shoots and roots of B. rapa by 55.7% and 46.6%, respectively, which was associated with the modulation of the expression of a set of genes accounting for Cd accumulation and transport. In the pot study, foliar spraying of thymol significantly decreased the Cd content in various vegetables, including leafy vegetables (B. rapa and two water spinach varieties, with leaf Cd decreasing by 40.5-45.9%) and solanaceous fruits and vegetables (three pepper varieties, with fruit Cd decreasing by 26.9-35.8%), which was accompanied by a growth-promoting effect. The results from this study elucidate the multifaceted function of thymol in helping vegetables detoxify Cd and decrease Cd bioaccumulation, shedding new light on developing thymol as a potential plant regulator to safeguard agroproduct security in Cd-polluted environments.

This commentary discusses new research showing that six structurally and functionally atypical NLR pairs in wheat confer disease resistance via a sensor NLR-helper NLR module. The functional mechanisms of some NLR pairs differ from the classical NLR pair model, revealing the complexity and diversity of the wheat immune system.

To explore the characteristic volatile compounds of 'Hujing Milu' peaches from different growing regions, headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) were employed to analyze volatile components in samples from six production areas. A total of 73 and 56 volatile compounds were identified by HS-SPME-GC-MS and HS-GC-IMS, respectively. Quantitative analysis revealed that esters, aldehydes, and alcohols were the main contributors to the aroma profile, accounting for over 70% of the total relative content. Combined with chemometric analysis (VIP > 1 and OAV/ROAV > 1), 17 potential biomarkers were identified that can distinguish 'Hujing Milu' peaches from different regions, including ethyl acetate, hexanol, (E)-2-nonenal, and dihydro-β-ionone. Moreover, soil properties of these regions and their correlation with volatile compounds were analyzed to elucidate the formation mechanisms of characteristic aromas. The results showed that ethyl acetate exhibited a significant positive correlation with soil pH (r = 0.530, p < 0.05), whereas dihydro-β-ionone showed a significant positive correlation with soil organic matter (r = 0.587, p < 0.05) and available potassium (r = 0.830, p < 0.05). This study identified characteristic volatile compounds of 'Hujing Milu' peaches from different regions, providing a reliable technical basis for origin traceability and the enhancement of aroma quality in 'Hujing Milu' peaches.

Besides suppressing immunity, pathogen effectors hijack host biosynthetic pathways, sugar transporters, enzymes, and transcriptional regulators for nutritional gain. In Xanthomonas, AvrBs2 drives de novo nutrient synthesis from a host metabolite, while PthA4 hijacks fruit ripening to release sugars. These findings pave the way for ‘anti-nutrition’ approaches for durable crop resistance.

INTRODUCTION:The continuous application of pesticides leads to persistent environmental residues that adversely affect non-target plants. However, the effect of pesticides on the endophytic microbial communities of plants and the feedback of enriched endophytes in alleviating pesticide-induced stress remain poorly understood. OBJECTIVES:This study aims to elucidate the roles and mechanisms by which endophytic bacteria collectively modulate rice plant resilience to chlorpyrifos (CP) stress. METHODS:We systematically compared the responses of axenic and holoxenic rice to six different pesticides. Using CP as a model, we analyzed the bacterial communities enriched in rice plants under CP stress and characterized the functional traits. Based on functional profiles, we then constructed synthetic consortia to investigate how interactions among bacterial functions drive the degradation pathway of CP in rice. RESULTS:Application of six different pesticides induced oxidative stress in rice, whereas endophytic bacteria alleviated growth inhibition. In response to CP stress, rice plants enriched endophytic bacteria from the phylum Proteobacteria, particularly Pseudomonas and Hydrogenophaga. We isolated 66 endobacterial strains, including 15 capable of CP degradation and 42 strains with growth-promoting properties. Functional combination experiments using Pseudomonas revealed that when degradation activity was present, increasing functional richness in synthetic microbial consortia further enhanced CP degradation in rice. Notably, the combination of CP-degrading strain p4 with non-degrading strain p6 exhibited a metabolic synergistic effect. Strain p4 transformed CP into eight metabolites via hydrolysis, oxidation, and alkylation, which were subsequently converted into less toxic conjugates through plant Phase II metabolism, a process promoted by strain p6. CONCLUSION:Our work demonstrates that the synergistic interaction between degrading and non-degrading endophytic bacteria enhances rice plant resistance to CP stress. These findings deepen our understanding of microbial mechanisms involved in plant responses to organic pollutants stress and provide insights for designing synthetic microbial consortia.

IntroductionSalt stress has emerged as a predominant abiotic factor that jeopardizes global crop growth and yield. The plant hormone salicylic acid (SA) has notable potential in mitigating salt toxicity, yet its mechanism in enhancing the salinity tolerance of tobacco plants is not well explored.MethodsThis study aimed to assess the potential benefits of exogenous SA application (1.0 mM) on tobacco seedlings subjected to saline soil conditions.ResultsThe foliar spray of SA partially mitigated these salt-induced effects, as evidenced by a reduction of malondialdehyde content, and improvements of leaf K+/Na+ ratios, pigment biosynthesis, and electron transport efficiency under NaCl stress. Additionally, SA increased the contents of total phenolic compound and soluble protein by 16.2% and 28.7% to alleviate NaCl-induced oxidative damage. Under salt stressed conditions, the activities of antioxidant enzymes, including superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase increased by 4.2%~14.4% in SA sprayed tobacco seedlings. Exogenous SA also increased ascorbate and glutathione levels and reduced their reduced forms by increasing the activities of glutathione reductase, ascorbate peroxidase, monodehydroascorbate reductase and dehydroascorbate reductase. qRT−PCR analysis revealed that the key genes regulating SA biosynthesis, carbon assimilation, the antioxidant system and the ascorbate−glutathione cycle were activated by SA under conditions of salt stress.DiscussionOur study elucidates the physiological and molecular mechanisms of exogenous SA in enhancing plant salt tolerance and provides a practical basis for crop improvement in saline environments.

The application of an environmentally friendly plant growth regulator to regulate plant growth and development represents a promising strategy for sustainable agriculture. Thymol is a kind of plant-derived natural compound. We have found that thymol is a potential biostimulant with the capability to trigger plant defense against abiotic stresses. Little is known about whether and how thymol modulates plant root system architecture. In this study, physiological, histochemical, and molecular approaches were applied to identify the role of thymol in promoting lateral root development in watermelon seedlings. Thymol significantly promoted LRP (lateral root primordia) initiation and lateral root formation. Rboh (respiratory burst oxidase homolog)-dependent reactive oxygen species (ROS) generation was involved in thymol-promoted lateral root development from LRP. Then, the Rboh gene family with nine members (ClRboh1–ClRboh9) was identified from watermelon genome. Thymol significantly induced the expression of a set of ClRbohs in roots. These results suggested that thymol was able to stimulate lateral root formation by triggering Rboh-dependent ROS production. These findings may help understand the biological function of thymol as an elicitor of lateral root in both applied and fundamental study.

The growing demand for cereal production has led to increasing agrochemical inputs; therefore, evaluation and adjustment of current practices are required to maintain and improve sustainable cropping systems. A Four-years study of multiple practices with reduced agrochemical application for rice farming was conducted and investigated in southern China to assess impacts on food safety and ecological resilience. A 30 % reduction in total pesticide use resulted in a 20 % decrease in ecological risk to earthworms, primarily due to reduced application of key pesticides: pymetrozine, pretilachlor, difenoconazole, propiconazole, thifluzamide, tricyclazole, and hexaconazole. A 22 % reduction in total mineral fertilizer use had a slight impact on soil fertility; however, certain practices involving partial replacement of chemical fertilizers with organic manure enhanced soil enzyme activity. This improvement was also linked to changes in the soil bacterial community, particularly the enrichment of Gemmatimonadetes, Actinobacteria, and Cyanobacteria, which contributed to enhanced soil fertility. Additionally, reduction in agrochemical application was accompanied by a declining trend in heavy metal accumulation; however, exposure risks of arsenic and Cd still require consideration. Our study demonstrates that progressive reduction of agrochemical inputs can mitigate pollutant risks and reactivate soil self-restoration processes, thereby enabling the design of adaptable sustainable cropping systems with optimized ecological trade-offs.

Salt stress represents one of the most critical abiotic constraints limiting global agricultural productivity by adversely affecting plant growth, metabolism, and yield. Soil salinization disrupts water uptake and nutrient homeostasis, leading to ionic toxicity, osmotic imbalance, and oxidative stress that collectively impair crop development. Cucumis melo, a major horticultural crop of significant economic value, exhibits high sensitivity to salinity. Recent advances have elucidated that melon adapts to salt stress through intricate physiological and molecular mechanisms involving osmotic adjustment, ion transport regulation, antioxidant defense, and transcriptional reprogramming. Several pivotal genes, such as CmNHX1, CmHKT1;1, CmCML13, CmAPX27, and CmRAV1, etc., have been identified to participate in multiple signaling pathways governing salt tolerance in melon. In this review, we comprehensively summarize the physiological effects of salt stress on melon growth, elucidating the key molecular mechanisms underlying salt tolerance, particularly those associated with ion homeostasis, antioxidant defense, and transcriptional regulation. The review further discusses current strategies and future perspectives for the genetic improvement of salt tolerance. Collectively, this review provides a theoretical framework and valuable reference for future research on the molecular basis of salt tolerance and breeding of salt-tolerant melon cultivars.

[Objective]Bagging is a significant practice in peach cultivation,which can alter the light conditions of the fruit and minimize mechanical damage to the fruit,enhance surface smoothness,and improve the overall visual quality of peaches.Additionally,bagging can reduce pesticide residues on peaches,thereby decreasing food safety risk.However,research on the impact of bagging on the nutri-tional quality of peach fruit is limited.The study aimed to evaluate the impact of bagging on the nutri-tional quality and mineral element content of peach fruit in various varieties.[Methods]Three peach varieties from Jiangsu including Baifeng,Xiacui,and Xiahui were tested.The treatment group under-went bagging,while the control group remained untreated.The peach samples at maturity stages were collected,and the fruit mass,firmness and soluble solid content were detected.The content of amino ac-ids,organic acids and total phenols were detected.Mineral elements including macronutrients and mi-cronutrients were analyzed using ICP and ICP-MS.[Results]Among the three varieties,Xiahui had the highest average mass(279.1 g),followed by Baifeng(248.3 g)and Xiacui(220.0 g).Xiacui exhibited the highest firmness(5.80),which was 1.87 times and 1.62 times that of Baifeng and Xiahui,respective-ly.There were no significant differences in the soluble solids content among the different varieties,which ranged from 10.4％to 11.1％(p＞0.05).For each variety,there were no significant differences in mass and firmness between the bagged and control samples(p＞0.05).However,compared with the un-bagged group,the soluble solids content in the bagged group significantly decreased for Baifeng,Xia-hui,and Xiacui by 16.6％,7.5％,and 17.9％,respectively(p＜0.05).Tthe contents of vitamin C,amino acids,and total phenols in the bagged group,were significantly lower than those in the control group,with reductions of 0.14-0.22,0.07-0.11 and 0.11-0.25 times,respectively(p＜0.05).The soluble sugar content in the bagged group significantly increased by 0.12-0.24 times in Xiahui and Xiacui,but showed no significant change in Baifeng(p＜0.05).The bagging significantly increased the contents of succinic acid and citric acid in Baifeng.In Xiacui,bagging significantly elevated the contents of succin-ic acid,quinic acid,and malic acid,and decreased the citric acid content significantly.Overall,the total acid content of bagged fruits in Xiahui was significantly reduced compared with the control fruits.Bag-ging significantly decreased the levels of Ca,Cu,K,Mg,Sr,Zn,and Ba in all three peach varieties,with reductions ranging from 0.1 to 0.8 times(p＜0.05).Additionally,the bagging reduced the Mn and Al contents in Xiacui and Xiahui by 0.2-0.5 and 0.1-0.2 times,respectively.The reductions in amino acids and mineral elements might be attributed to the effect of bagging on reducing the opening of fruit stomata,leading to decreased water influx and consequently lower levels of photosynthetic products and mineral elements in the peaches.The decrease in total phenol content might be related to reduced fruit coloration due to bagging.[Conclusion]The bagging did not affect fruit mass or firmness but sig-nificantly reduced the contents of soluble solids,vitamin C,amino acids,total phenols,and most miner-al elements,leading to reduce the nutritional quality of the peach fruits.These findings would provide valuable insights for the assessment of peach cultivation practices.

Plants are engaged in a constant battle for survival against pathogens, which triggers a multifaceted immune response characterized by pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) to prevent infection. These two immune responses operate synergistically to enhance plant immunity. PTI is considered the first line of defense involving the recognition of pathogen-associated molecular patterns (PAMPs) by specific receptors in host cells known as pattern recognition receptors (PRRs), which initiate defense signaling. However, many pathogens often overcome the first line of defense (PTI) and successfully deploy effector proteins to promote virulence and subvert plant immunity, leading to host susceptibility. In the counter-defense, the ETI defense mechanism is activated by triggering resistance (R) genes in plants that usually encode nucleotide-binding-leucine-rich-containing (NLR) proteins. During plant-pathogen interactions, transcriptional reprogramming of defense-related genes such as pathogenesis-related proteins and generation of reactive oxygen species (ROS) are essential for facilitating programmed cell death at the infected location to inhibit pathogen proliferation. While ROS and PR protein are critical in plant-pathogen interaction, they are not universally required or effective against all pathogens. Hence, plants’ multilayer immune layer is encrypted with the compensatory activation of ETI defense response towards the failure of one component of the defense system to maintain robust immunity.

Salicylic acid (SA) is a phytohormone that plays a critical role in plant growth, development, and response to unfavorable conditions. Over the past three decades, researches on SA have deeply elucidated the mechanism of its function in plants tolerance to infection by biotrophic and hemibiotrophic pathogens. Recent studies have found that SA also plays an important role in regulating plants response to abiotic stress. It is emerging as a strong tool for alleviating adverse effects of biotic and abiotic stresses in crop plants. During SA-mediated stress responses, many small molecules participate in the SA modification or signaling, which play important regulatory roles. The cooperations of small molecules in SA pathway remain least discussed, especially in terms of SA-induced abiotic stress tolerance. This review provides an overview of the recent studies about SA and its relationship with different small molecules and highlights the critical functions of small molecules in SA-mediated plant stress responses.

Accumulating pesticide residues in ecosystems pose environmental risks and raise serious public health concerns. Plant-microbe interactions have been applied in the phytoremediation of pesticides to ensure food safety and reduce environmental health risks. However, the plant signaling molecules triggered by microbes to degrade pesticides remain unclear. Herein, we demonstrated that CS8-gfp, a growth-promoting strain, promoted degradation of two pesticides (herbicide atrazine, ATZ and insecticide thiamethoxam, TMX) in rice plants. An RNA-sequencing (RNA-seq) study of CS8-gfp inoculated/uninoculated rice revealed differential expression (>2 fold change, P < 0.05) of 12 jasmonic acid (JA)-related genes and JA content was increased in CS8-gfp-inoculated rice plants. To validate the role of JA in this process, the mutant osopr7 defective in JA synthesis was generated by gene-editing technologies. Analysis of physiological responses and pesticides residues revealed that osopr7 impaired the ability of CS8-gfp to alleviate ATZ/TMX toxicity and reduce ATZ/TMX content in rice plants. Using LC-QTOF-MS/MS, we characterized eighteen of ATZ and fifteen of TMX degradation products, and three ATZ derivatives and eight TMX conjugates were identified for the first time in rice plants. Moreover, the enhancement of degradation products in wild type plants was 1.03-4.56 times (ATZ) and 1.27-5.08 times (TMX) higher than that in osopr7 under CS8-gfp colonization. These results suggest that activation of the JA pathway in rice by CS8-gfp accelerates ATZ/TMX detoxification. Our work provides the first evidence of JA-mediated microbial detoxification of pesticides in rice and reveals the underlying mechanism for growth-promoting bacteria to eliminate pesticides in crops and reduces environmental risks to human health through the food chain.

Bacterial communities play significant roles in desert ecosystems through diverse interactions, including participation in rhizolith formation and establishment of root symbioses, yet related evidence remain limited. Using 16S rRNA amplicon sequencing, diversity metrics and co-occurrence network analyses, this study explored bacterial communities of rhizolith- and root-associated soils in the Tengeri Desert, China, with a focus on their potential role in carbonate precipitation. We identified significant differences in bacterial communities across root/soil types. The co-occurrence network was simpler in root-associated soils compared to bulk soils. Rhizolithassociated soils harbored unique taxa with low alpha diversity but with enriched specialists Propionibacterium, Corynebacterium and Acinetobacter linked to carbonate genesis. Our study provides new insights into plant-microbe-mineral interactions in desert ecosystems.

Plants can recruit beneficial rhizomicrobes to combat environmental stimuli, but the upstream signaling through which plants sense stress to initiate rhizomicrobial recruitment still remains unclear. This study elucidates the role of long-distance ROS signaling in driving the recruitment of beneficial rhizobacteria to establish systemic acclimation following local organic pollutant stress. Plant leaves sense various organic pollutants to generate ROS, followed by the occurrence of a long-distance ROS wave from leaves to roots via a Ca2+-RBOH-ROS signaling module. Elevated ROS in roots plays dual functions. First, ROS stimulates plant carbon release into the rhizosphere by increasing the permeability of root cell membranes. The released carbon flux enriches plant-beneficial bacterial genera, which in turn promotes plant growth and pollutant degradation. Second, NO acts downstream of ROS to loosen root cell walls, facilitating rhizobacterial colonization. Our findings show how plants deploy systemic signaling acquire help from rhizomicrobes, extending our understanding of plant environmental adaptability.