Optimizing antidiabetic properties of Galega officinalis extract: Investigating the effects of foliar application of chitosan and salicylic acid.

Diabetes poses a significant global health burden, demanding safe and effective therapeutic interventions. Medicinal plants offer promising avenues for natural diabetic management. Galega officinalis (goat's rue) has long been recognized for its hypoglycemic potential, but optimizing its phytochemical content and antidiabetic activity remains a key challenge. This study aimed to address this aspect by investigating the impact of foliar application of chitosan and salicylic acid on the physiological and phytochemical properties of G. officinalis, and subsequently evaluating its antidiabetic efficacy compared to that of the established drug metformin. A randomized complete block design with three replications was employed. Laboratory mice were divided into treatment groups receiving G. officinalis extract from plants sprayed with four salicylic acid concentrations (0.5-3 mM/L) and four chitosan concentrations (0-0.8 g/L). Blood glucose levels and various physiological parameters were assessed. Chitosan at 0.4 g/L and salicylic acid at 2 mM significantly enhanced the growth, photosynthetic pigments, and antioxidant activity of G. officinalis. Notably, the extract from plants treated with 3 mM salicylic acid exhibited the highest total alkaloid content, a potential contributor to antidiabetic activity. In a separate study, diabetic mice treated with this optimized G. officinalis extract (50 mg/kg) exhibited significantly greater blood glucose reductions compared to those treated with metformin (500 mg). This study demonstrates the potential of chitosan and salicylic acid in optimizing the beneficial properties of G. officinalis. The extract derived from plants treated with 3 mM salicylic acid displayed superior blood glucose-lowering efficacy compared to metformin, suggesting its promising role as a potential natural antidiabetic therapy. Further research is warranted to elucidate the specific bioactive compounds responsible for this enhanced activity and translate these findings into clinical applications.

Differential contribution of Arabidopsis chitin receptor complex components to defense signaling and ubiquitination-dependent endocytotic removal from the plasma membrane.

In Arabidopsis, the enzymatically active lysin motif-containing receptor-like kinase (LysM-RLK) CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) and the pseudokinases LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE 5 (LYK5) and LYK4 are the core components of the canonical chitin receptor complex. CERK1 dimerizes and autophosphorylates upon chitin binding, resulting in activation of chitin signaling. In this study, we clarified and further elucidated the individual contributions of LYK4 and LYK5 to chitin-dependent signaling using mutant (combination)s and stably transformed Arabidopsis plants expressing fluorescence-tagged LYK5 and LYK4 variants from their endogenous promoters. Our analyses revealed that LYK5 interacts with CERK1 upon chitin treatment, independently of LYK4 and vice versa. We show that chitin-induced autophosphorylation of CERK1 is predominantly dependent on LYK5, whereas chitin-triggered ROS generation is almost exclusively mediated by LYK4. This suggests specific signaling functions of these two co-receptor proteins apart from their redundant function in mitogen-activated protein kinase (MAPK) signaling and transcriptional reprogramming. Moreover, we demonstrate that LYK5 is subject to chitin-induced and CERK1-dependent ubiquitination, which serves as a signal for chitin-induced internalization of LYK5. Our experiments provide evidence that a combination of phosphorylation and ubiquitination events controls LYK5 removal from the plasma membrane via endocytosis, which likely contributes to receptor complex desensitization.

Duality of H2O2 detoxification and immune activation of Ralstonia solanacearum alkyl hydroperoxide reductase C (AhpC) in tobacco.

Although microbial pathogens utilize various strategies to evade plant immunity, host plants have evolved powerful defense mechanisms that can be activated in preparation for threat by infective organisms. Here, we identified one 24 kDa alkyl hydroperoxide reductase C (AhpC) from the culture supernatant of Ralstonia solanacearum strain FQY-4 (denoted RsAhpC) in the presence of host roots. RsAhpC contributes to H2O2 detoxification and the pathogenicity of R. solanacearum. However, the introduction of RsAhpC into the apoplast could activate immune defense, leading to suppression of pathogen colonization in both Nicotiana benthamiana and the Honghua Dajinyuan (HD) cultivar of N. tabacum. Consequently, overexpression of RsAhpC in the HD cultivar enhanced the resistance of tobacco to bacterial wilt disease caused by FQY-4. Overall, this study provides insight into the arms race between pathogens and their plant hosts. Specifically, it is firstly reported that plants can sense pathogen-derived AhpC to activate defenses, in addition to the role of AhpC in pathogen ROS detoxification. Therefore, the macromolecule AhpC produced by Ralstonia solanacearum has the ability to enhance plant defense as an elicitor, which provides a practical strategy for disease resistance breeding.

Peer review of the pesticide risk assessment of the active substance Pythium oligandrum strain B301.

The conclusions of EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State Belgium for the pesticide active substance Pythium oligandrum strain B301 and the considerations as regards the inclusion of the substance in Annex IV of Regulation (EC) No 396/2005 are reported. The context of the peer review was that required by Regulation (EC) No 1107/2009 of the European Parliament and of the Council. The conclusions were reached on the basis of the evaluation of the representative uses of Pythium oligandrum strain B301 as a resistance inducer/elicitor to control trunk diseases on grapevines. The reliable endpoints, appropriate for use in regulatory risk assessment, are presented. Missing information identified as being required by the regulatory framework is listed. Concerns are reported where identified.

Carbohydrate elicitor-induced plant immunity: Advances and prospects.

The perceived negative impacts of synthetic agrochemicals gave way to alternative, biological plant protection strategies. The deployment of induced resistance, comprising boosting the natural defense responses of plants, is one of those. Plants developed multi-component defense mechanisms to defend themselves against biotic and abiotic stresses. These are activated upon recognition of stress signatures via membrane-localized receptors. The induced immune responses enable plants to tolerate and limit the impact of stresses. A systemic cascade of signals enables plants to prime un-damaged tissues, which is crucial during secondary encounters with stress. Comparable stress tolerance mechanisms can be induced in plants by the application of carbohydrate elicitors such as chitin/chitosan, ß-1,3-glucans, oligogalacturonides, cellodextrins, xyloglucans, alginates, ulvans, and carrageenans. Treating plants with carbohydrate-derived elicitors enable the plants to develop resistance appliances against diverse stresses. Some carbohydrates are also known to have been involved in promoting symbiotic signaling. Here, we review recent progresses on plant resistance elicitation effect of various carbohydrate elicitors and the molecular mechanisms of plant cell perception, cascade signals, and responses to cascaded cues. Besides, the molecular mechanisms used by plants to distinguish carbohydrate-induced immunity signals from symbiotic signals are discussed. The structure-activity relationships of the carbohydrate elicitors are also described. Furthermore, we forwarded future research outlooks that might increase the utilization of carbohydrate elicitors in agriculture in order to improve the efficacy of plant protection strategies.

Wound-induced small-peptide-mediated signaling cascade, regulated by OsPSKR, dictates balance between growth and defense in rice.

Wounding is a general stress in plants that results from various pest and pathogenic infections in addition to environment-induced mechanical damages. Plants have sophisticated molecular mechanisms to recognize and respond to wounding, with those of monocots being distinct from dicots. Here, we show the involvement of two distinct categories of temporally separated, endogenously derived peptides, namely, plant elicitor peptides (PEPs) and phytosulfokine (PSK), mediating wound responses in rice. These peptides trigger a dynamic signal relay in which a receptor kinase involved in PSK perception named OsPSKR plays a major role. Perturbation of OsPSKR expression in rice leads to compromised development and constitutive autoimmune phenotypes. OsPSKR regulates the transitioning of defense to growth signals upon wounding. OsPSKR displays mutual antagonism with the OsPEPR1 receptor involved in PEP perception. Collectively, our work indicates the presence of a stepwise peptide-mediated signal relay that regulates the transition from defense to growth upon wounding in monocots.

Prunus dulcis response to novel defense elicitor peptides and control of Xylella fastidiosa infections.

KEY MESSAGE: New defense elicitor peptides have been identified which control Xylella fastidiosa infections in almond. Xylella fastidiosa is a plant pathogenic bacterium that has been introduced in the European Union (EU), threatening the agricultural economy of relevant Mediterranean crops such as almond (Prunus dulcis). Plant defense elicitor peptides would be promising to manage diseases such as almond leaf scorch, but their effect on the host has not been fully studied. In this work, the response of almond plants to the defense elicitor peptide flg22-NH2 was studied in depth using RNA-seq, confirming the activation of the salicylic acid and abscisic acid pathways. Marker genes related to the response triggered by flg22-NH2 were used to study the effect of the application strategy of the peptide on almond plants and to depict its time course. The application of flg22-NH2 by endotherapy triggered the highest number of upregulated genes, especially at 6 h after the treatment. A library of peptides that includes BP100-flg15, HpaG23, FV7, RIJK2, PIP-1, Pep13, BP16-Pep13, flg15-BP100 and BP16 triggered a stronger defense response in almond plants than flg22-NH2. The best candidate, FV7, when applied by endotherapy on almond plants inoculated with X. fastidiosa, significantly reduced levels of the pathogen and decreased disease symptoms. Therefore, these novel plant defense elicitors are suitable candidates to manage diseases caused by X. fastidiosa, in particular almond leaf scorch.

Genetically-clustered antifungal phytocytokines and receptor protein family members cooperate to trigger plant immune signaling.

Phytocytokines regulate plant immunity by cooperating with cell-surface proteins. Populus trichocarpa RUST INDUCED SECRETED PEPTIDE 1 (PtRISP1) exhibits an elicitor activity in poplar, as well as a direct antimicrobial activity against rust fungi. PtRISP1 gene directly clusters with a gene encoding a leucine-rich repeat receptor protein (LRR-RP), that we termed RISP-ASSOCIATED LRR-RP (PtRALR). In this study, we used phylogenomics to characterize the RISP and RALR gene families, and molecular physiology assays to functionally characterize RISP/RALR pairs. Both RISP and RALR gene families specifically evolved in Salicaceae species (poplar and willow), and systematically cluster in the genomes. Despite a low sequence identity, Salix purpurea RISP1 (SpRISP1) shows properties and activities similar to PtRISP1. Both PtRISP1 and SpRISP1 induced a reactive oxygen species (ROS) burst and mitogen-activated protein kinases (MAPKs) phosphorylation in Nicotiana benthamiana leaves expressing the respective clustered RALR. PtRISP1 also triggers a rapid stomatal closure in poplar. Altogether, these results suggest that plants evolved phytocytokines with direct antimicrobial activities, and that the genes coding these phytocytokines co-evolved and physically cluster with genes coding LRR-RPs required to initiate immune signaling.

Tissue-Specific Natural Synthesis of Galanthaminein Zephyranthes Species and Its Accumulation in Different In Vitro-Grown Organs Following Methyl Jasmonate Treatment.

Galanthamine is an immensely valuable alkaloid exhibiting anti-cancer and antiviral activity. The cultivation of plant tissues in in vitro conditions is a good source for the synthesis and enrichment of secondary metabolites of commercial interest. In this study, the Amaryllidaceae alkaloid galanthamine was quantified in three Zephyranthes species, such as Zephyranthes candida, Zephyranthes grandiflora, and Zephyranthes citrina, and the impact of the methyl jasmonate (MJ) signaling molecule on galanthamine accumulation was monitored in in vitro-derived plant tissues. This is the first ever study of the MJ-regulated accumulation of galanthamine in in vitro-grown Zephyranthes tissues. Shoot regeneration was obtained in all three Zephyranthes species on Murashige and Skoog (MS) medium containing 2.0 mgL-1 benzylaminopurine (BAP) + 0.5 mgL-1 naphthalene acetic acid (NAA). The regenerated shoots were rooted on a medium containing 2.0 mgL-1 indole butyric acid (IBA). A GC-MS study of Zephyranthes extracts revealed the presence of 34 phyto-compounds of varied levels with therapeutic activities against diseases. The galanthamine content was quantified in plant parts of the three Zephyranthes species using high-performance thin layer chromatography (HPTLC); the maximum was found in Z. candida bulb (2.41 µg g-1 dry wt.), followed by Z. grandiflora (2.13 µg g-1 dry wt.), and then Z. citrina (2.02 µg g-1 dry wt.). The galanthamine content showed bulb > leaf > root source order. The in vitro-generated plantlets were treated with different MJ concentrations, and the galanthamine yield was measured in bulb, leaf, and root tissues. The highest galanthamine content was recorded in bulbs of Z. candida (3.97 µg g-1 dry wt.) treated with 150 µM MJ, showing an increase of 64.73% compared to the control. This accumulation may be attributed to MJ-induced stress, highlighting the potential commercial synthesis of galanthamine in vitro.

In Vitro: The Extraordinary Enhancement in Rutin Accumulation and Antioxidant Activity in Philodendron "Imperial Red" Plantlets Using Ti-Mo-Ni-O Nanotubes as a Novel Elicitor.

Rutin, a flavonoid phytochemical compound, plays a vital role in human health. It is used in treating capillary fragility and has anti-Alzheimer, anti-inflammatory, and antioxidant effects. In this study, Ti-Mo-Ni-O nanotubes (NTs) were used, for the first time, in an unprecedented plant biotechnology application, wherein in vitro Philodendron shoots (Philodendron erubescens) known as "Imperial Red" were targeted for rutin accumulation. The antioxidant responses and the accumulation of rutin were evaluated in treated Philodendron erubescens (P. erubescens) shoots using 5.0 mg/L of Ti-Mo-Ni-O NTs. The total phenolic content and total flavonoid content were estimated, and an ABTS+ assay, FRAP assay, and iron metal chelation assay were performed. The application of Ti-Mo-Ni-O NTs enhanced the rutin content considerably from 0.02 mg/g to 2.96 mg/g for dry-weight shootlet extracts. Therefore, the use of Ti-Mo-Ni-O NTs is proposed to be a superior alternative to elevate the rutin content. The aim of the current study is to target P. erubescens shoots grown in vitro for the accumulation of rutin compounds using Ti-Mo-Ni-O NT powder, to determine the quantitative and qualitative accumulation of rutin via HPLC-DAD analysis, and to estimate the antioxidant activity of P. erubescens shoot extract. This study presents a novel methodology for utilizing nano-biotechnology in the synthesis of plant secondary metabolites.

Enhanced Antioxidant, Anti-Aging, Anti-Tyrosinase, and Anti-Inflammatory Properties of Vanda coerulea Griff. Ex Lindl. Protocorm through Elicitations with Chitosan.

This study aimed to investigate the effects of elicitors on Vanda coerulea Griff. Ex Lindl. protocorms to enhance bioactive compound production and evaluate their biological activities relevant to cosmeceutical applications. The protocorms were developed from the callus treated with different elicitors, including 6-benzylaminopurine (BA), methyl jasmonate (MeJA), and chitosan. Both the adult plant and protocorms were extracted by maceration in 80% methanol and investigated for their chemical compositions using high-performance liquid chromatography. The extracts were evaluated for antioxidant, anti-collagenase, anti-elastase, and anti-tyrosinase activities. In addition, anti-inflammatory properties were assessed using a real-time polymerase chain reaction. The irritation potency was evaluated using the hen's egg test-chorioallantoic membrane test. The findings revealed that protocorms treated with BA and chitosan developed a greener color, while those treated with MeJA exhibited a distinct darker coloration. Elicitation with BA and chitosan resulted in protocorms with comparable or higher levels of syringic acid, rutin, and quercin compared with the adult plant, with rutin being the most prominent identified compound. Furthermore, rutin was reported as the compound responsible for all biological activities. The chitosan-treated protocorm extract exhibited potent inhibition against oxidation, collagenase, elastase, tyrosinase, and inflammatory cytokines, along with a nonirritating effect, making it a promising candidate for cosmeceutical applications.

Modifications in gene expression and phenolic compounds content by methyl jasmonate and fungal elicitors in Ficus carica. Cv. Siah hairy root cultures.

BACKGROUND: One of the most effective strategies to increase phytochemicals production in plant cultures is elicitation. In the present study, we studied the effect of abiotic and biotic elicitors on the growth, key biosynthetic genes expression, antioxidant capacity, and phenolic compounds content in Rhizobium (Agrobacterium) rhizogenes-induced hairy roots cultures of Ficus carica cv. Siah. METHODS: The elicitors included methyl jasmonate (MeJA) as abiotic elicitor, culture filtrate and cell extract of fungus Piriformospora indica as biotic elicitors were prepared to use. The cultures of F. carica hairy roots were exposed to elicitores at different time points. After elicitation treatments, hairy roots were collected, and evaluated for growth index, total phenolic (TPC) and flavonoids (TFC) content, antioxidant activity (2,2-diphenyl-1-picrylhydrazyl, DPPH and ferric ion reducing antioxidant power, FRAP assays), expression level of key phenolic/flavonoid biosynthesis genes, and high-performance liquid chromatography (HPLC) analysis of some main phenolic compounds in comparison to control. RESULTS: Elicitation positively or negatively affected the growth, content of phenolic/flavonoid compounds and DPPH and FRAP antioxidant activities of hairy roots cultures in depending of elicitor concentration and exposure time. The maximum expression level of chalcone synthase (CHS: 55.1), flavonoid 3'-hydroxylase (F3'H: 34.33) genes and transcription factors MYB3 (32.22), Basic helix-loop-helix (bHLH: 45.73) was induced by MeJA elicitation, whereas the maximum expression level of phenylalanine ammonia-lyase (PAL: 26.72) and UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT: 27.57) genes was obtained after P. indica culture filtrate elicitation. The P. indica elicitation also caused greatest increase in the content of gallic acid (5848 µg/g), caffeic acid (508.2 µg/g), rutin (43.5 µg/g), quercetin (341 µg/g), and apigenin (1167 µg/g) phenolic compounds. CONCLUSIONS: This study support that elicitation of F. carica cv. Siah hairy roots can be considered as an effective biotechnological method for improved phenolic/flavonoid compounds production, and of course this approach requires further research.

Effects of elicitors from culture filtrate of Fusarium solani CL105 on flavonoid production of Scutellaria baicalensis calli.

Introduction: Endophytic fungi can promote secondary metabolite accumulation in medicinal plants. Previously, we observed that the culture filtrate of Fusarium solani CL105 promoted flavonoid production in Scutellaria baicalensis calli. However, the active ingredients and mechanisms associated with this secondary metabolite accumulation remain unclear. Methods: This study evaluates the effects of different elicitors from the culture filtrate of F. solani CL105 namely, exopolysaccharide (EPS), exoprotein (EP), and other parts (OP), on the flavonoid production in S. baicalensis calli by HPLC. Subsequently, the underlying mechanism of EPS induced flavonoid production in S. baicalensis calli was revealed by transcriptomics and RT-PCR. Results and discussion: The results indicated a significant increase in flavonoid production in S. baicalensis calli following treatment with EPS. Baicalin (1.40 fold), wogonoside (1.91 fold), and wogonin (2.76 fold) were most significantly up-regulated compared with the control. Transcriptome analysis further revealed up-regulation of key enzyme genes (CHS, CHI, FNS, and F6H) involved in flavonoid synthesis after 5 days of EPS treatment. Moreover, the expression of GA2ox and CYP707A-genes involved in gibberellin acid (GA) and abscisic acid biosynthesis (ABA), respectively-were significantly up-regulated. The expression levels of certain transcription factors, including MYB3, MYB8, and MYB13, were also significantly higher than in controls. Our results indicated that EPS was a main active elicitor involved in promoting flavonoid production in S. baicalensis calli. We postulated that EPS might stimulate the expression of MYB3, MYB8, MYB13, GA2ox, and CYP707A, leading to markedly upregulated CHS, CHI, FNS, and F6H expression levels, ultimately promoting flavonoid synthesis. This study provides a novel avenue for large-scale in vitro production of flavonoids in S. baicalensis.

Enhancement of Plumbagin Production through Elicitation in In Vitro-Regenerated Shoots of Plumbago indica L.

Plumbago indica L. contains a valuable bioactive compound called plumbagin. Elicited regenerated shoots grown in vitro could be another source of high-yielding plumbagin. The purpose of this investigation was to examine the effects of elicitor type and concentration, as well as elicitation period, on plumbagin content in in vitro-regenerated shoots of P. indica. Nodal explants were cultured on Murashige and Skoog (MS) medium containing 1 mg/L benzyladenine (BA) in combination with 0-150 mg/L yeast extract or 50-150 µM salicylic acid for four weeks. Plumbagin levels of 3.88 ± 0.38% and 3.81 ± 0.37% w/w g dry extract were achieved from the 50 and 100 mg/L yeast extract-elicited shoots, which were higher than the value obtained for the control. However, the addition of salicylic acid did not increase the plumbagin content. In the elicitation period experiment, nodal explants were cultured on MS medium supplemented with 1 mg/L BA and 50 mg/L yeast extract for durations of three, four and five weeks. The 4-week yeast extract-elicited shoot had a maximum plumbagin content of 3.22 ± 0.12% w/w g dry extract, greater than that of the control. In summary, the plumbagin content of the in vitro P. indica shoots was enhanced by 4-week elicitation using 50 mg/L yeast extract.

Exogenous of different elicitors: proline and ornithine on Sansevieria trifasciata under particulate matter (PM) and volatile organic compounds (VOC).

Phytoremediation has become famous for removing particulate matter (PM) and volatile organic compounds (VOC) in situ. Plants for removing PM and VOC were associated with botanical biofilters to attract pollution to the plant. On the other hand, persistent pollution exposure can lower plant health and phytoremediation effectiveness; therefore, improving plant tolerance against stress is necessary. Various elicitors can enhance plant tolerance to certain stressors. This study aims to investigate different elicitors to maintain plant health and improve the use of plants in phytoremediation for PM and VOC pollution. This experiment used Sansevieria trifasciata hort. ex Prain under PM and VOC stress. Exogenous elicitors, such as proline, ornithine, and a commercial product, were applied to the leaf parts before exposure to PM and VOC stress. The initial concentrations of PM1, PM2.5, and PM10 were 300-350, 350-450, and 400-500 µg m-3, respectively, while the VOC concentration was 2.5-3.0 mg m-3. The plant was stressed for 7 days. The result indicated that ornithine 10 mM is vital in improving plant tolerance and inducing antioxidant enzymes against PM and VOC, while proline 50 mM and a commercial product could not reduce plant stress. This study suggests that ornithine might be an important metabolite to improve plant tolerance to PM and VOC.

Peptide REF1 is a local wound signal promoting plant regeneration.

Plants frequently encounter wounding and have evolved an extraordinary regenerative capacity to heal the wounds. However, the wound signal that triggers regenerative responses has not been identified. Here, through characterization of a tomato mutant defective in both wound-induced defense and regeneration, we demonstrate that in tomato, a plant elicitor peptide (Pep), REGENERATION FACTOR1 (REF1), acts as a systemin-independent local wound signal that primarily regulates local defense responses and regenerative responses in response to wounding. We further identified PEPR1/2 ORTHOLOG RECEPTOR-LIKE KINASE1 (PORK1) as the receptor perceiving REF1 signal for plant regeneration. REF1-PORK1-mediated signaling promotes regeneration via activating WOUND-INDUCED DEDIFFERENTIATION 1 (WIND1), a master regulator of wound-induced cellular reprogramming in plants. Thus, REF1-PORK1 signaling represents a conserved phytocytokine pathway to initiate, amplify, and stabilize a signaling cascade that orchestrates wound-triggered organ regeneration. Application of REF1 provides a simple method to boost the regeneration and transformation efficiency of recalcitrant crops.

Exogenous Melatonin Enhances Dihydrochalcone Accumulation in Lithocarpus litseifolius Leaves via Regulating Hormonal Crosstalk and Transcriptional Profiling.

Dihydrochalcones (DHCs) constitute a specific class of flavonoids widely known for their various health-related advantages. Melatonin (MLT) has received attention worldwide as a master regulator in plants, but its roles in DHC accumulation remain unclear. Herein, the elicitation impacts of MLT on DHC biosynthesis were examined in Lithocarpus litseifolius, a valuable medicinal plant famous for its sweet flavor and anti-diabetes effect. Compared to the control, the foliar application of MLT significantly increased total flavonoid and DHC (phlorizin, trilobatin, and phloretin) levels in L. litseifolius leaves, especially when 100 µM MLT was utilized for 14 days. Moreover, antioxidant enzyme activities were boosted after MLT treatments, resulting in a decrease in the levels of intracellular reactive oxygen species. Remarkably, MLT triggered the biosynthesis of numerous phytohormones linked to secondary metabolism (salicylic acid, methyl jasmonic acid (MeJA), and ethylene), while reducing free JA contents in L. litseifolius. Additionally, the flavonoid biosynthetic enzyme activities were enhanced by the MLT in leaves. Multiple differentially expressed genes (DEGs) in RNA-seq might play a crucial role in MLT-elicited pathways, particularly those associated with the antioxidant system (SOD, CAT, and POD), transcription factor regulation (MYBs and bHLHs), and DHC metabolism (4CL, C4H, UGT71K1, and UGT88A1). As a result, MLT enhanced DHC accumulation in L. litseifolius leaves, primarily by modulating the antioxidant activity and co-regulating the physiological, hormonal, and transcriptional pathways of DHC metabolism.

The Truncated Peptide AtPEP1(9-23) Has the Same Function as AtPEP1(1-23) in Inhibiting Primary Root Growth and Triggering of ROS Burst.

Currently, the widely used active form of plant elicitor peptide 1 (PEP1) from Arabidopsis thaliana is composed of 23 amino acids, hereafter AtPEP1(1-23), serving as an immune elicitor. The relatively less conserved N-terminal region in AtPEP family indicates that the amino acids in this region may be unrelated to the function and activity of AtPEP peptides. Consequently, we conducted an investigation to determine the necessity of the nonconserved amino acids in AtPEP1(1-23) peptide for its functional properties. By assessing the primary root growth and the burst of reactive oxygen species (ROS), we discovered that the first eight N-terminal amino acids of AtPEP1(1-23) are not crucial for its functionality, whereas the conserved C-terminal aspartic acid plays a significant role in its functionality. In this study, we identified a truncated peptide, AtPEP1(9-23), which exhibits comparable activity to AtPEP1(1-23) in inhibiting primary root growth and inducing ROS burst. Additionally, the truncated peptide AtPEP1(13-23) shows similar ability to induce ROS burst as AtPEP1(1-23), but its inhibitory effect on primary roots is significantly reduced. These findings are significant as they provide a novel approach to explore and understand the functionality of the AtPEP1(1-23) peptide. Moreover, exogenous application of AtPEP1(13-23) may enhance plant resistance to pathogens without affecting their growth and development. Therefore, AtPEP1(13-23) holds promise for development as a potentially applicable biopesticides.

Molecular characterization revealed the role of thaumatin-like proteins of Rhizoctonia solani AG4-JY in inducing maize disease resistance.

The gene family of thaumatin-like proteins (TLPs) plays a crucial role in the adaptation of organisms to environmental stresses. In recent years, fungal secreted proteins (SP) with inducing disease resistance activity in plants have emerged as important elicitors in the control of fungal diseases. Identifying SPs with inducing disease resistance activity and studying their mechanisms are crucial for controlling sheath blight. In the present study, 10 proteins containing the thaumatin-like domain were identified in strain AG4-JY of Rhizoctonia solani and eight of the 10 proteins had signal peptides. Analysis of the TLP genes of the 10 different anastomosis groups (AGs) showed that the evolutionary relationship of the TLP gene was consistent with that between different AGs of R. solani. Furthermore, it was found that RsTLP3, RsTLP9 and RsTLP10 were regarded as secreted proteins for their signaling peptides exhibited secretory activity. Prokaryotic expression and enzyme activity analysis revealed that the three secreted proteins possess glycoside hydrolase activity, suggesting they belong to the TLP family. Additionally, spraying the crude enzyme solution of the three TLP proteins could enhance maize resistance to sheath blight. Further analysis showed that genes associated with the salicylic acid and ethylene pathways were up-regulated following RsTLP3 application. The results indicated that RsTLP3 had a good application prospect in biological control.

The proteomic landscape of fall armyworm oral secretion reveals its role in plant adaptation.

BACKGROUND: The fall armyworm (FAW, Spodoptera frugiperda (J.E. Smith)) is a polyphagous agricultural pest with rapidly evolving adaptations to host plants. We found the oral secretion (OS) of FAW from different plants influences plant defense response differentially, suggesting its role in adapting to host plants. However, the protein expression profile of FAW OS respond to different plants is largely unknown. RESULTS: Here, from the mass spectrometry assay, we identified a total of 256 proteins in the OS of FAW fed on cotton (Gossypium hirsutum L.), tobacco (Nicotiana benthamiana Domin), maize (Zea mays L.) and artificial diet. The FAW OS primarily comprise of 60 proteases, 32 esterases and 92 non-enzymatic proteins. It displays high plasticity across different diets. We found that more than half of the esterases are lipases which have been reported as insect elicitors to enhance plant defense response. The lipase accumulation in cotton-fed larvae was the highest, followed by maize-fed larvae. In the presence of lipase inhibitors, the enhanced induction on defense genes in wounded leaves by OS was attenuated. However, the putative effectors were most highly accumulated in the OS from FAW larvae fed on maize compared to those fed on other diets. We identified that one of them (VRLP4) reduces the OS-mediated induction on defense genes in wounded leaves. CONCLUSION: Together, our investigation presents the proteomic landscape of the OS of FAW influenced by different diets and reveals diet-mediated plasticity of OS is involved in FAW adaptation to host plants. © 2024 Society of Chemical Industry.