Plant Defense Mechanisms Research Articles

Assessment of potential candidate genes for partial resistance to Sclerotinia stem rot caused by Sclerotinia sclerotiorum using real-time quantitative PCR.

Sclerotinia stem rot (SSR), caused by Sclerotinia sclerotiorum (Lib) de Bary (S. sclerotiorum), is one of the most important diseases that causes significant soybean [Glycine max (L.) Merr.] seed yield and quality losses in Canada and globally. Initiation of plant defense mechanisms is crucial for establishing partial resistance to the pathogenic fungus. To understand plant response to S. sclerotiorum, we conducted a temporal (1, 3, and 5 days post-inoculation [DPI]) assessment of gene expression changes in the stem of soybean genotypes with contrasting phenotypic response. We focused on four genes that have been previously reported as associated with SSR partial resistance and are known to be involved in defense-related functions such as cell wall modification, signaling, response to wounding, and response to fungus. The results showed a higher and earlier expression of the genes in partially resistant cultivars compared to the susceptible. Expression of some genes increased up to 11- (Glyma.02G059700) to 16-fold (Glyma.09G232100) by 3 DPI in the partially resistant cultivar, OAC Drayton, while the genes were generally downregulated in the susceptible cultivar, OAC Shire, at the same DPI. This study improves our understanding of expression patterns of genes involved in plant defense against fungal pathogens in soybean. More importantly, the knowledge of genes that are essential in defense against S. sclerotiorum can be used to fine-map the quantitative trait loci for SSR resistance and facilitate accelerated breeding of SSR-resistant cultivars through gene-based marker-assisted selection.

Fatty Acid ABCG Transporter GhSTR1 Mediates Resistance to Verticillium dahliae and Fusarium oxysporum in Cotton

Verticillium wilt and Fusarium wilt cause significant losses in cotton (Gossypium hirsutum) production and have a significant economic impact. This study determined the functional role of GhSTR1, a member of the ABCG subfamily of ATP-binding cassette (ABC) transporters, that mediates cotton defense responses against various plant pathogens. We identified GhSTR1 as a homolog of STR1 from Medicago truncatula and highlighted its evolutionary conservation and potential role in plant defense mechanisms. Expression profiling revealed that GhSTR1 displays tissue-specific and spatiotemporal dynamics under stress conditions caused by Verticillium dahliae and Fusarium oxysporum. Functional validation using virus-induced gene silencing (VIGS) showed that silencing GhSTR1 improved disease resistance, resulting in milder symptoms, less vascular browning, and reduced fungal growth. Furthermore, the AtSTR1 loss-of-function mutant in Arabidopsis thaliana exhibited similar resistance phenotypes, highlighting the conserved regulatory role of STR1 in pathogen defense. In addition to its role in disease resistance, the mutation of AtSTR1 in Arabidopsis also enhanced the vegetative and reproductive growth of the plant, including increased root length, rosette leaf number, and plant height without compromising drought tolerance. These findings suggest that GhSTR1 mediates a trade-off between defense and growth, offering a potential target for optimizing both traits for crop improvement. This study identifies GhSTR1 as a key regulator of plant–pathogen interactions and growth dynamics, providing a foundation for developing durable strategies to enhance cotton’s resistance and yield under biotic and abiotic stress conditions.

Half-Century Scientometric Analysis: Unveiling the Excellence of Fungi as Biocontrol Agents and Biofertilisers

Reducing the use of chemical inputs is becoming a major challenge in developing sustainable agriculture. Fungi, known as biocontrol agents (BCAs) and biofertilisers, are crucial in scientific research and are celebrated for their efficacy, eco-friendliness, and multifaceted roles. In this study, a bibliometric analysis was conducted on 5349 articles related to fungi as BCAs and biofertilisers over the past half-century using the Web of Science Core Collection (WoSCC) database. The publications on fungi, such as BCAs and biofertilisers, have increased significantly over the last 20 years, with a maximum growth rate of 33.7%. The USA and China lead in this field. Keyword clustering analysis revealed that entomopathogenic fungi, including Hemiptera, Coleoptera, and Lepidoptera, can be used to manage plant pests. It also showed that fungi can be used as biofertilisers to promote plant growth. The analysis of research trends shows that Beauveria bassiana in biological control is highly significant. This study also showed that entomopathogenic fungi control plant pests by infiltrating the insect cuticles. Trichoderma spp. exert biocontrol effects by producing antibiotics. Arbuscular mycorrhizal fungi can trigger plant defence mechanisms by modulating secondary metabolite synthesis. This study contributes to the current knowledge of fungi as BCAs and biofertilisers and can guide future research.

Transcriptomic and Phenotypic Responses of CucumberTrichome Density to Silver Nitrate and Sodium Thiosulfate Application

Cucumber (Cucumis sativus L.) is one of the most widely cultivated crops worldwide and is valued for its nutritional, economic, and ecological benefits. The regulation of defense mechanisms against herbivores, along with osmotic loss and environmental regulation, is greatly affected by trichomes in cucumbers. In this study, we attempted to characterize trichomes and examined fruit physiological and transcriptome profiles by RNA sequencing in cucumber breeding lines 6101-4 and 5634-1 at three stages of fruit development through foliar application with a combination of silver nitrate (AgNO3) and sodium thiosulfate (Na2S2O3) in comparison to non-treated controls. Notable increases in the number of trichomes and altered forms were observed for both inbred cultivars 6101-4 and 5634-1 against foliar application of chemical substances. RNA-seq analysis was performed to identify differentially expressed genes (DEGs) involved in multiple pathways in cucumber trichome formation. The enrichment of differentially expressed transcripts showed that foliar application upregulated the expression of many stress-responsive and trichome-associated genes including plant hormone signal transduction, sesquiterpenoid and triterpenoid biosynthesis, and the mitogen-activated protein kinase (MAPK) signaling pathway. The dominant regulatory genes, such as allene oxide synthase (AOS) and MYB1R1 transcription factor, exhibited significant modulations in their expression in response to chemical application. The RNA-seq results were further confirmed by RT-PCR-based analysis, which revealed that after chemical application, the dominant regulatory genes, such as allene oxide synthase (AOS), PTB 19, MYB1R1, bHLH62-like, MADS-box transcription factor, and salicylic acid-binding protein 2-like, were differentially expressed, implying that these DEGs involved in multiple pathways are involved the positive regulation of the initiation and development of trichomes in C. sativus. A comparison of trichome biology and associated gene expression regulation in other plant species has shown that silver nitrate (AgNO3) and sodium thiosulfate (Na2S2O3) are also responsible for hormonal and signaling pathway regulation. This study improves our knowledge of the molecular mechanisms involved in C. sativus trichome development. It also emphasizes the possibility of utilizing chemical composition to modulate C. sativus trichome-related characteristics of C. sativus, leading to the improvement of plant defense mechanisms as well as environmental adaptation.

Induced Systemic Resistance-Mediated Defense Against Alternaria Blight Disease in Lentil by Pesticide Degrading Plant Growth-Promoting Rhizobacteria.

Enzymatic and antioxidative responses are key defense mechanisms in plants following pathogen invasion, collectively known as induced systemic resistance (ISR). Alternaria sp., a well-known soil-borne pathogen, causes blight diseases in various crops. This study investigates the defence response in lentil plants through the treatment-induced application of two multipotent pesticide degrading plant growth-promoting rhizobacteria (PGPR), Bacillus cereus and Bacillus safensis, to mitigate the destructive effects of Alternaria. Both bacterial strains were applied in different carrier-based bioformulations via soil drenching. We assessed the modulation of defense-related enzymes by various combinational treatments with the Alternaria pathogen. The in vitro production of antimicrobial compounds was analyzed using GC-MS to confirm their pathogen-suppressive capabilities. Field trials showed a positive correlation between treatments and improvements in yield and growth index (GI). The highest (180%) enzymatic induction of phenylalanine ammonia lyase (PAL) followed by catalase (CAT)(100%) and polyphenol oxidase (PPO) (54%), was observed in treatments with B. cereus alone or in combination with B. safensis, in presence of Alternaria, in respect to the control. In vitro analysis revealed the production of antimicrobial compounds, including benzoic acid derivatives, cyclotetrasiloxanes, hexacosane, chlorpyrifos, and phthalates, which may contribute to pathogen suppression. Our findings demonstrate that these biocontrol agents (BCAs) not only stimulate the plant's enzymatic defense system but also enhance growth, seed yield and produce several antimicrobial compounds in vitro. Thus, pesticide-tolerant PGPR, used in this study, exhibit both disease control and plant growth-promoting properties, offering promising applications in sustainable agriculture.

Ozone exposure alters nutrients and stoichiometric ratios in different organs of four urban tree species despite limited negative effects on leaf physiology and plant growth and biomass

To better understand the effects of ground-level ozone (O3) on nutrients and stoichiometry in different plant organs, urban tree species Celtis sinensis, Cyclocarya paliurus, Quercus acutissima, and Quercus nuttallii were subjected to a constant exposure to charcoal-filtered air (CF), nonfiltered air (NF), or NF + 40, 60, or 80 nmol O3 mol–1 (NF40, NF60, and NF80) starting early in the summer of the growing season. At the end of summer, net CO2 assimilation rate (A), stomatal conductance (gs), leaf mass per area (LMA), and/or leaf greenness (SPAD) either were not significantly affected by elevated O3 or were even higher in some cases during the summer compared with the CF or NF controls. LMA was significantly lower in autumn only after the highest O3 exposures. Compared to NF, NF40 caused a large increase in gs across species in late summer and more K and Mn in stems. At the end of the growing season, nutrient status and stoichiometric ratios in different organs were variously altered under O3 stress; many changes were large and often species-specific. Across O3 treatments, LMA was primarily associated with C and Mg levels in leaves and Ca levels in leaves and stems. NF40 enriched K, P, Fe, and Mn in stems, relative to NF, and NF60 enhanced Ca in leaves relative to CF and NF40. Moreover, NF resulted in a higher Ca/Mg ratio in leaves of Q. acutissima only, relative to the other O3 regimes. Interestingly, across species, O3 stress led to different nutrient modifications in different organs (stems + branches vs leaves). Thus, ambient and/or elevated O3 exposures can alter the dynamics and distribution of nutrients and disrupt stoichiometry in different organs in a species-specific manner. Changes in stoichiometry reflect an important defense mechanism in plants under O3, and O3 pollution adds more risk to ecological stoichiometries in urban areas.

Novel ZnO-TiO2@MSC nanomaterial based on corn stover template enhances disease resistance in tomato plants.

Crop diseases significantly threaten global food security, driving the need for innovative control strategies. This study explored using ZnO-TiO2@MSC, a novel nanomaterial synthesized using a corn stover template, to enhance disease resistance in tomato plants. In vitro assays demonstrated potent antimicrobial activity of ZnO-TiO2@MSC against the pathogen Pseudomonas syringae pv. tomato DC3000 (Pst. DC3000) by disrupting bacterial cell membranes and modulating oxidative stress-related gene expression. When applied to tomato leaves in pot trials, ZnO-TiO2@MSC achieved 79.83% control of bacterial leaf spot disease while promoting plant growth and photosynthesis. The nanomaterial triggered plant defense mechanisms, upregulating resistance genes and increasing the activities of key enzymes. Metabolomic profiling revealed elevated lipids, lipid-like molecules, and organic acid derivative levels in treated leaves, suggesting cell membrane remodeling as part of the defense response. These findings highlight the potential of biologically-templated nanomaterials like ZnO-TiO2@MSC as multifunctional tools for sustainable disease management in crops. The corn stover-based synthesis approach also provides a way to valorize agricultural waste. Further research is needed to understand the long-term impacts and viability of field-scale application of ZnO-TiO2@MSC as an alternative to conventional pesticides.

Transcription factors HmeWRKY33 and HmeWRKY51 regulate the susceptibility of pitaya to canker disease.

Pitaya canker disease, caused by Neoscytalidium dimidiatum, is the primary threat to pitaya cultivation, significantly compromising fruit quality and reducing yield. WRKY transcription factors are essential regulators in plant pathogen recognition and defense mechanisms, yet their specific roles in the development of pitaya canker disease remain largely unexplored. In this study, five genes (HmeWRKY33, HmeWRKY51, HmePR1, HmeHsp70, and HmeSERK) associated with pitaya canker disease were identified through RNA-Seq analysis. The expression levels of HmeWRKY33 and HmeWRKY51 were upregulated following N. dimidiatum infection. Transient transformation revealed that these five genes negatively influenced the resistance of Nicotiana benthamiana leaves to canker disease, while promoting the accumulation of reactive oxygen species (ROS) and inducing cell death. Yeast one-hybrid and dual-luciferase reporter assays revealed that HmeWRKY33 directly activated the expression of HmeSERK, while HmeWRKY51 directly inhibited the expression of HmePR1 and HmeHsp70, co-participating in regulating the susceptibility of 'Youcihuanglong' pitaya to canker. These findings provide a theoretical basis for breeding new canker-resistant pitaya varieties through genetic transformation.

Elucidation of the biosynthetic pathways of timosaponins reveals the antifungal mechanisms in Anemarrhena asphodeloides.

Timosaponins, as steroidal saponins, are the primary active constituents and quality biomarkers in Anemarrhena asphodeloides Bunge. Despite their significance, the biosynthetic pathways of timosaponins have not been thoroughly investigated. This study aims to delineate the biosynthetic pathway of timosaponins in A. asphodeloides, elucidate the catalytic mechanisms of the key cycloartenol synthase (CAS), and investigate the antifungal properties of timosaponins. Genes were cloned from A. asphodeloides and heterologous expressed in yeast, tobacco or bacillus coli. Site-directed mutagenesis and molecular docking were used to elucidate the catalytic mechanism of CAS. Antifungal assays were conducted to evaluate the antifungal activities of timosaponins. In this study, we elucidated the biochemical functions of seven genes involved in timosaponins biosynthesis in A. asphodeloides. Among three candidate OSC genes, AaOSCR12 was identified as the gene encoding cycloartenol synthase, which is responsible for the skeleton cyclization in timosaponin biosynthesis. Six residues (257H, 369N, 448T, 507V, 558P, 616Y) were identified as the critical catalytic active sites of CAS (AaOSCR12). Sterol methyltransferase (AaSMT1) and sterol side-chain reductase (AaSSR2) were found to be the subsequent enzymes and the branching points leading to phytosterol and cholesterol biosynthesis, respectively. Two oxide reductase genes, AaCYP90B27 and AaCYP90B2, were responsible for post-modification of cholesterol, serving as a precursor of timosaponins. A key 26-O-β-glucosidase (AaF26G1) was identified as facilitating the conversion of furostanol-type timosaponins into spirostanol-type timosaponins. Antifungal assays revealed that spirostanol-type timosaponin AⅢ exhibits superior antifungal activity compared to furostanol-type timosaponin BⅡ, potentially linked to plant defense mechanisms involving AaF26G1. This study utilized a multi-chassis cross-identification strategy, revealing key enzymes in the timosaponin biosynthetic pathway and offering novel insights into plant defense mechanisms against microbial pathogens.

Fortifying plant fortresses: siderophores in defense against Cercospora leaf spot disease in Vigna radiata L.

Siderophores, specialized iron-chelating molecules produced by Bacillus amyloliquefaciens D5, were investigated for their role in enhancing plant defense mechanisms against Cercospora canescens in mung bean (Vigna radiata L.). Siderophores were extracted and purified using Amberlite XAD-4 and applied to plants at concentrations of 5, 10, and 15 µg/mL, followed by pathogen inoculation. The treatments significantly influenced enzymatic activities and defense-related gene expression. On Day 6, peroxidase (POD) activity reached its highest value of 0.563 in the SP15 (siderophore + pathogen at 15 µg/mL) treatment, with S15 (siderophore-only at 15 µg/mL) showing a lower but significant increase of 0.453, while control groups remained unchanged. Polyphenol oxidase (PPO) activity peaked in SP15 (0.10 U/mL), followed by S15 (0.08 U/mL), highlighting the role of these treatments in enhancing stress responses. Chitinase activity was significantly elevated in SP15 on Day 6, with a sustained response through Day 8, while no significant change was observed in the control group. Total phenolic content was highest in SP15 (100 µg/mL), showing a a ramified immune response whereas S15 recorded 80 µg/mL, significantly above the control. Gene expression analysis further demonstrated the effectiveness of siderophore and siderophore + pathogen treatments. Catalase expression was upregulated by 21.1-fold in siderophore-only treatment and amplified to 25.9-fold in SP15. Epoxide hydrolase (EH) gene expression increased by 77.3-fold in S15 and further synergized to over 90-fold in SP15. Similarly, PR10 expression showed moderate upregulation in S15 and significantly higher levels in SP15, reflecting enhanced pathogen defense. Calmodulin (CAL) gene expression was moderately regulated in S15 but significantly amplified in SP15. These findings underscore the dual role of siderophores in nutrient acquisition and as potent elicitors of plant defenses, highlighting their potential as bio-stimulants. Field trials are essential to validate these results under natural conditions and optimize their use in agriculture.

From Recognition to Response: Resistance–Effector Gene Interactions in the Brassica napus and Leptosphaeria maculans Patho-System

Blackleg disease, caused by the hemibiotrophic fungal pathogen Leptosphaeria maculans, poses a serious threat to Brassica crops and requires a broad understanding of the plant defence mechanisms. The Brassica. napus-L. maculans pathosystem provides a useful model to understand plant resistance response to hemibiotrophs. This review aims to explain the mechanisms underlying R-Avr interaction, signalling cascades, and the hypersensitive response (HR) produced by B. napus towards L. maculans, causing local cell death that restricts the pathogen to the site of infection. The role of transcription factors is pivotal to the process of HR, coordinating the regulation of genes involved in pathogen recognition and the activation of SA responsive genes and production of secondary metabolites. The R-Avr interaction signalling cascade involves production of reactive oxygen species (ROS), calcium ion influx, Salicylic acid (SA) hormonal signalling and mitogen activated protein kinases (MAPKs), which are critical in the HR in B. napus. The in-depth understanding of molecular signalling pathway of the R-Avr interaction between B. napus-L. maculans pathosystem provides valuable information for future research endeavours regarding enhancing disease resistance in Brassica crops.

"Methyl jasmonate: bridging plant defense mechanisms and human therapeutics".

A volatile organic substance produced from jasmonic acid, methyl jasmonate (MJ/MeJA), is an important plant hormone involved in stress responses and plant defense. Apart from its role in plants, MJ has garnered significant attention because of its pharmacological effects and possible therapeutic use in human health. This thorough analysis looks into the many biological actions of MJ, such as its antioxidant, anti-inflammatory, and anti-cancer effects. The underlying mechanism of these actions is examined, emphasizing MJ's ability to modulate important signaling pathways, cause cancer cells to undergo apoptosis, and boost immunological responses. Furthermore, MJ's capacity to manage long-term illnesses like cancer and neurological conditions like Parkinson's and Alzheimer's is examined. Preclinical and clinical research are beginning to provide evidence that MJ may be a useful medicinal drug. Nevertheless, more research is needed to fully understand its mode of action, enhance its administration methods, and evaluate its efficacy and safety in humans. This review highlights MJ's therapeutic promise and supports earlier research into its pharmacological capabilities and possible medical applications. This abstract highlights methyl jasmonate's pharmacological effects and therapeutic potential by providing a concise overview of the main topics covered in a thorough review.

Overexpression of E. coli formaldehyde metabolic genes pleiotropically promotes Arabidopsis thaliana growth by regulating redox homeostasis.

Formaldehyde (FA) is a hazardous pollutant causing acute and chronic poisoning in humans. While plants provide a natural method of removing FA pollution, their ability to absorb and degrade FA is limited. To improve the ability of plants to degrade FA, we introduced the E. coli FrmA gene into Arabidopsis thaliana alone (FrmAOE lines) or with FrmB (FrmA/BOE lines). The transgenic seedlings had approximately 30 % longer primary roots and a 20 % higher fresh weight than the control plants. The transgenic plants started flowering four days earlier and had about 30 % more kilo-seed weight than the wild type. FrmA/BOE and FrmAOE accumulated 40 % more reactive oxidative species (ROS) in mesophyll protoplasts and leaf tissue than wild-type plants under normal conditions. In the presence of FA, they produced 92 % and 26 % more glutathione (GSH) and 6 % and 4 % more ascorbate (AsA), respectively, compared to wild-type plants and thus scavenged FA-induced ROS more effectively. The degradation efficiency of the transgenic leaf extract for FA was 73 % and 44 % higher than that of the wild type, respectively, which was also emphasized by a 2 %-26 % increase in the activity of antioxidant enzymes such as SOD and APx. By revealing the functional divergence between microbial and plant FA metabolic pathways, our work has not only highlighted the promising pluripotency of microbial genes in promoting normal plant growth and detoxifying organic pollutants simultaneously, but also revealed another layer of complexity of plant defense mechanisms against organic toxins related to ROS scavenging.

Characterizing Pathogen-Induced Changes in Black Walnut Volatile Organic Compounds Following Inoculation with Geosmithia Morbida, The Causal Agent of Thousand Cankers Disease.

Thousand cankers disease (TCD) is a pathosystem comprised of Juglandacea spp., a pathogenic fungus Geosmithia morbida, and an insect vector, the walnut twig beetle (WTB) (Pityophthorus juglandis). Of the North American Juglans species, Juglans nigra is the most susceptible to TCD and has resulted in significant decline and mortality of urban and plantation trees in the western United States. Geosmithia morbida causes necrotic cankers in the phloem, and infected trees may release an array of volatile compounds that act as important chemical cues to WTB. Here, we aimed to determine how J. nigra volatile profiles respond to G. morbida infection as these changes can offer valuable insights into plant defense mechanisms and potentially influence WTB behavior, thus impacting disease transmission dynamics. In this study, we collected a series of bark and leaf volatiles from J. nigra seedlings inoculated with one of three isolates of G. morbida and a sham-inoculated control. Our results suggest J. nigra bark responds to G. morbida infection, with the western United States isolate (RN-2) eliciting a distinct volatile response compared to other treatments. We identified six out of fourteen compounds that contribute to 80% of the dissimilarity between RN-2 and sham-inoculated control trees. Inoculation with isolate RN-2 elicited the largest change in volatile profiles and resulted in the smallest cankers in the phloem, suggesting these compounds my play important defensive roles in J. nigra against the fungal pathogen that causes TCD.

The Combination of α-Fe2O3 NP and Trichoderma sp. Improves Antifungal Activity Against Fusarium Wilt.

Soil-borne plant pathogens are the most damaging pathogens responsible for severe crop damage. A conventional chemotherapy approach to these pathogens has numerous environmental issues, while biological control agents (BCAs) are less promising under field conditions. There is an immediate need to develop an integrated strategy for utilizing nanoparticles and biocontrol to manage soil-borne pathogens, such as Fusarium wilt, effectively. Simulation of BCA metabolites to nanoparticle biocontrol metabolites is considered the most effective biocontrol approach. Combining Fe2O3 nanoparticles and Trichoderma in nursery and field conditions manages pathogens and increases plant growth characteristics. The present study evaluated the commercial biocontrol strains and the use of NPFe in combination with Trichoderma harzianum to enhance the biocontrol potential of T. harzianum against soil-borne pathogens. The effectiveness of (NPFe + T. harzianum) was evaluated under in vitro conditions where combination was found most effective upto (87.63%) mycelial growth inhibition of pathogen and under field conditions lowest pooled Fusarium wilt incidence (19.54%) was recorded. Nanocomposites are beneficial for agricultural sustainability and environmental safety by upregulating the expression of genes linked to these processes, Fe NPs can activate plant defense mechanisms and increase plant resistance to pathogenic invasions. Additionally, as iron is a necessary component for plant growth and development, Fe NPs promote better nutrient uptake.

Effectiveness of Plant-Induced Resistance Against Root-Knot Nematode Depends on the Policy of Using Inducer on the Host Plant.

This research was conducted to determine the relationship between plant defense responses and the extent of treatment applied to either the aerial parts or roots of the plant. The experimental treatments included different methods of application (spraying versus soil drenching), varying treatment areas (one-sixth, one-third, half, or all of the plant's aerial parts and roots) with SA, and infecting the plants with root-knot nematodes. Evaluation of plant growth and nematode pathogenicity indices in the greenhouse section, H2O2 accumulation rate, and phenylalanine ammonia lyase enzyme activity (in aerial parts and roots) were carried out in biochemical experiments. The results showed that treating less than one-third of the aerial parts with salicylic acid (SA) did not significantly impact plant growth or nematode pathogenicity indices. However, it did lead to a notable increase in hydrogen peroxide (H2O2) accumulation, while phenylalanine ammonia lyase (PAL) enzyme activity remained unchanged. In contrast, treating more than one-third of the aerial parts resulted in decreased nematode pathogenicity and enhanced production of defense compounds. Notably, treatments targeting the roots consistently demonstrated a more pronounced effect on nematode suppression and increased defense compound levels, emphasizing the importance of root treatment, as this is where nematodes are primarily present. Overall, the study highlights the differential impact of treatment location and extent on plant defense mechanisms and suggests that strategic targeting of either aerial or root tissues can optimize plant responses against nematode attacks.

Nanoparticles as catalysts of agricultural revolution: enhancing crop tolerance to abiotic stress: a review.

Ensuring global food security and achieving sustainable agricultural productivity remains one of the foremost challenges of the contemporary era. The increasing impacts of climate change and environmental stressors like drought, salinity, and heavy metal (HM) toxicity threaten crop productivity worldwide. Addressing these challenges demands the development of innovative technologies that can increase food production, reduce environmental impacts, and bolster the resilience of agroecosystems against climate variation. Nanotechnology, particularly the application of nanoparticles (NPs), represents an innovative approach to strengthen crop resilience and enhance the sustainability of agriculture. NPs have special physicochemical properties, including a high surface-area-to-volume ratio and the ability to penetrate plant tissues, which enhances nutrient uptake, stress resistance, and photosynthetic efficiency. This review paper explores how abiotic stressors impact crops and the role of NPs in bolstering crop resistance to these challenges. The main emphasis is on the potential of NPs potential to boost plant stress tolerance by triggering the plant defense mechanisms, improving growth under stress, and increasing agricultural yield. NPs have demonstrated potential in addressing key agricultural challenges, such as nutrient leaching, declining soil fertility, and reduced crop yield due to poor water management. However, applying NPs must consider regulatory and environmental concerns, including soil accumulation, toxicity to non-target organisms, and consumer perceptions of NP-enhanced products. To mitigate land and water impacts, NPs should be integrated with precision agriculture technologies, allowing targeted application of nano-fertilizers and nano-pesticides. Although further research is necessary to assess their advantages and address concerns, NPs present a promising and cost-effective approach for enhancing food security in the future.

Emerging Trends in Secondary Metabolite Research in Caryophyllales: Betalains and Their Roles in Plant Adaptation and Defense Mechanisms.

Betalains, a distinctive group of nitrogen-containing pigments exclusive to the Caryophyllales order, possess diverse biological activities such as antioxidant, anti-inflammatory, and antimicrobial properties, making them highly valuable for applications in food, nutraceutical, and pharmaceutical industries. This Review provides a comprehensive analysis of betalain biosynthesis, structural diversity, and ecological significance, highlighting their roles in enhancing stress resilience, adaptation mechanisms, and plant evolutionary strategies. The evolutionary development of betalains is explored, revealing their emergence through gene duplication events and providing insights into their mutual exclusivity with anthocyanins. This study utilizes comparative genetics and advanced molecular tools to uncover the intricate regulatory networks involving transcription factors such as MYB, bHLH, WRKY, and SPL, which govern betalain biosynthesis. Furthermore, the Review discusses innovative transgenic studies that introduce betalains into non-native species, demonstrating their potential to enhance stress tolerance and boost agricultural productivity. While significant progress has been made in understanding betalain biosynthesis pathways, the evolutionary relationships with anthocyanins and the specific ecological functions of betalains in plants remain areas of ongoing exploration. Future research directions include integrating chemotaxonomic studies, molecular phylogenetics, and multiomics approaches to unravel the full spectrum of betalain functions and regulatory mechanisms. Such studies are essential to deepening our understanding of these vibrant pigments and their evolutionary implications, offering new opportunities for biotechnological innovations and sustainable agricultural practices. This Review stands out by combining genetic, ecological, and evolutionary perspectives, providing novel insights into the multifunctionality of betalains and their potential to drive future advancements in plant science and biotechnology.

Fig abscission as a defense mechanism of Ficus trees against parasitism by non-pollinating fig wasps

How does the fig tree Ficus benguetensis protect its investment in the production of figs and pollinating fig wasps against parasitism from non-pollinating fig wasps? This study documents a previously overlooked defense mechanism: fig abscission—the natural shedding of the fig fruit as a defense mechanism. Our bagging experiments showed that both the absence of pollination and high parasitism levels lead to the abortion of F. benguetensis figs, with positive correlations between parasitism levels, increased abscission rates, and decreased pollinator production. Moreover, we found that high parasitism corresponds to shortened fig development periods until abscission, while medium parasitism levels result in fewer pollinators. Our findings suggest that abscission may function as a resource conservation strategy, as most of the tree’s investment in the figs occurs post-pollination. This study uncovers for the first time the use of fig abscission as a unique defense against non-pollinating fig wasp parasites, broadening our understanding of plant defense mechanisms within mutualistic interactions.

Integration of Genetic Resistance Mechanisms in Sustainable Crop Breeding Programs-A Review

The integration of genetic resistance mechanisms into sustainable crop breeding programs is critical for addressing global agricultural challenges, including the increasing threats posed by pests, diseases, and climate change. Genetic resistance, which involves the use of innate plant defense mechanisms, provides an environmentally friendly alternative to chemical controls and plays a pivotal role in enhancing crop resilience. Advances in molecular biology, such as CRISPR-Cas9 gene editing and multi-omics technologies (genomics, transcriptomics, and metabolomics), have revolutionized resistance breeding, enabling the precise identification, modification, and deployment of resistance traits. These tools facilitate the development of crops with enhanced resistance to biotic and abiotic stresses while reducing yield penalties and linkage drag. Challenges such as the evolution of pathogen virulence, the breakdown of race-specific resistance genes, and the trade-offs between resistance and crop quality remain significant hurdles. Durable resistance, achieved by combining qualitative and quantitative resistance traits, offers a promising approach to mitigate these issues and delay resistance breakdown. Agroecological practices, such as crop diversification, companion planting, and organic amendments, can complement genetic resistance by reducing pathogen pressure and improving ecosystem stability. International research collaborations, such as those led by CGIAR, along with local capacity-building efforts, are essential to ensure the equitable dissemination of resistance technologies, particularly in resource-limited regions. Despite these advances, socioeconomic and regulatory barriers, including public skepticism toward genetically engineered crops and stringent approval processes for GMOs and gene-edited varieties, hinder widespread adoption. Increased investments in breeding research, streamlined regulatory frameworks, and policies promoting resistant varieties are vital to overcoming these challenges. As the global demand for food continues to rise amidst climate uncertainties, the integration of cutting-edge genetic tools, ecological principles, and collaborative efforts offers a pathway to more sustainable and resilient agricultural systems. By addressing current limitations and leveraging emerging technologies, genetic resistance can significantly contribute to global food security and the sustainability of modern farming practices.