A tale of many families: calcium channels in plant immunity.

Plants launch a concerted immune response to dampen potential infections upon sensing microbial pathogen and insect invasions. The transient and rapid elevation of the cytosolic calcium concentration [Ca2+]cyt is among the essential early cellular responses in plant immunity. The free Ca2+ concentration in the apoplast is far higher than that in the resting cytoplasm. Thus, the precise regulation of calcium channel activities upon infection is the key for an immediate and dynamic Ca2+ influx to trigger downstream signaling. Specific Ca2+ signatures in different branches of the plant immune system vary in timing, amplitude, duration, kinetics, and sources of Ca2+. Recent breakthroughs in the studies of diverse groups of classical calcium channels highlight the instrumental role of Ca2+ homeostasis in plant immunity and cell survival. Additionally, the identification of some immune receptors as noncanonical Ca2+-permeable channels opens a new view of how immune receptors initiate cell death and signaling. This review aims to provide an overview of different Ca2+-conducting channels in plant immunity and highlight their molecular and genetic mode-of-actions in facilitating immune signaling. We also discuss the regulatory mechanisms that control the stability and activity of these channels.

Potato calcium sensor modules StCBL3-StCIPK7 and StCBL3-StCIPK24 negatively regulate plant immunity.

BACKGROUND: Potato late blight, caused by Phytophthora infestans, is the most devastating disease on potato. Dissecting critical immune components in potato will be supportive for engineering P. infestans resistance. Upon pathogens attack, plant Ca2+ signature is generated and decoded by an array of Ca2+ sensors, among which calcineurin B-like proteins (CBLs) coupled with plant specific CBL-interacting protein kinases (CIPKs) are much less explored in plant immunity. RESULTS: In this study, we identified that two differential potato CBL-CIPK modules regulate plant defense responses against Phytophthora and ROS production, respectively. By deploying virus-induced gene silencing (VIGS) system-based pathogen inoculation assays, StCBL3 was shown to negatively regulate Phytophthora resistance. Consistently, StCBL3 was further found to negatively regulate PTI and ETI responses in Nicotiana benthamiana. Furthermore, StCIPK7 was identified to act together with StCBL3 to negatively regulate Phytophthora resistance. StCIPK7 physically interacts with StCBL3 and phosphorylates StCBL3 in a Ca2+-dependent manner. StCBL3 promotes StCIPK7 kinase activity. On the other hand, another StCBL3-interacting kinase StCIPK24 negatively modulating flg22-triggered accumulation of reactive oxygen species (ROS) by interacting with StRBOHB. CONCLUSIONS: Together, these findings demonstrate that the StCBL3-StCIPK7 complex negatively modulates Phytophthora resistance and StCBL3-StCIPK24 complex negatively regulate ROS production. Our results offer new insights into the roles of potato CBL-CIPK in plant immunity and provide valuable gene resources to engineer the disease resistance potato in the future.

MAB-DrNet: Bearing Fault Diagnosis Method Based on an Improved Dilated Convolutional Neural Network.

Rolling bearing fault diagnosis is of great significance to the safe and reliable operation of manufacturing equipment. In the actual complex environment, the collected bearing signals usually contain a large amount of noises from the resonances of the environment and other components, resulting in the nonlinear characteristics of the collected data. Existing deep-learning-based solutions for bearing fault diagnosis perform poorly in classification performance under noises. To address the above problems, this paper proposes an improved dilated-convolutional-neural network-based bearing fault diagnosis method in noisy environments named MAB-DrNet. First, a basic model called the dilated residual network (DrNet) was designed based on the residual block to enlarge the model's perceptual field to better capture the features from bearing fault signals. Then, a max-average block (MAB) module was designed to improve the feature extraction capability of the model. In addition, the global residual block (GRB) module was introduced into MAB-DrNet to further improve the performance of the proposed model, enabling the model to better handle the global information of the input data and improve the classification accuracy of the model in noisy environments. Finally, the proposed method was tested on the CWRU dataset, and the results showed that the proposed method had good noise immunity; the accuracy was 95.57% when adding Gaussian white noises with a signal-to-noise ratio of -6 dB. The proposed method was also compared with existing advanced methods to further prove its high accuracy.

A pair of G-type lectin receptor-like kinases modulates nlp20-mediated immune responses by coupling to the RLP23 receptor complex.

Plant cells recognize microbial patterns with the plasma-membrane-localized pattern-recognition receptors consisting mainly of receptor kinases (RKs) and receptor-like proteins (RLPs). RKs, such as bacterial flagellin receptor FLS2, and their downstream signaling components have been studied extensively. However, newly discovered regulatory components of RLP-mediated immune signaling, such as the nlp20 receptor RLP23, await identification. Unlike RKs, RLPs lack a cytoplasmic kinase domain, instead recruiting the receptor-like kinases (RLKs) BAK1 and SOBIR1. SOBIR1 specifically works as an adapter for RLP-mediated immunity. To identify new regulators of RLP-mediated signaling, we looked for SOBIR1-binding proteins (SBPs) in Arabidopsis thaliana using protein immunoprecipitation and mass spectrometry, identifying two G-type lectin RLKs, SBP1 and SBP2, that physically interacted with SOBIR1. SBP1 and SBP2 showed high sequence similarity, were tandemly repeated on chromosome 4, and also interacted with both RLP23 and BAK1. sbp1 sbp2 double mutants obtained via CRISPR-Cas9 gene editing showed severely impaired nlp20-induced reactive oxygen species burst, mitogen-activated protein kinase (MAPK) activation, and defense gene expression, but normal flg22-induced immune responses. We showed that SBP1 regulated nlp20-induced immunity in a kinase activity-independent manner. Furthermore, the nlp20-induced the RLP23-BAK1 interaction, although not the flg22-induced FLS2-BAK1 interaction, was significantly reduced in sbp1 sbp2. This study identified SBPs as new regulatory components in RLP23 receptor complex that may specifically modulate RLP23-mediated immunity by positively regulating the interaction between the RLP23 receptor and the BAK1 co-receptor.

A malectin-like receptor kinase regulates cell death and pattern-triggered immunity in soybean.

Plant cells can sense conserved molecular patterns through pattern recognition receptors (PRRs) and initiate pattern-triggered immunity (PTI). Details of the PTI signaling network are starting to be uncovered in Arabidopsis, but are still poorly understood in other species, including soybean (Glycine max). In this study, we perform a forward genetic screen for autoimmunity-related lesion mimic mutants (lmms) in soybean and identify two allelic mutants, which carry mutations in Glyma.13G054400, encoding a malectin-like receptor kinase (RK). The mutants exhibit enhanced resistance to both bacterial and oomycete pathogens, as well as elevated ROS production upon treatment with the bacterial pattern flg22. Overexpression of GmLMM1 gene in Nicotiana benthamiana severely suppresses flg22-triggered ROS production and oomycete pattern XEG1-induced cell death. We further show that GmLMM1 interacts with the flg22 receptor FLS2 and its co-receptor BAK1 to negatively regulate flg22-induced complex formation between them. Our study identifies an important component in PTI regulation and reveals that GmLMM1 acts as a molecular switch to control an appropriate immune activation, which may also be adapted to other PRR-mediated immune signaling in soybean.

Ubiquitination of Receptorsomes, Frontline of Plant Immunity.

Sessile plants are constantly exposed to myriads of unfavorable invading organisms with different lifestyles. To survive, plants have evolved plasma membrane-resident pattern recognition receptors (PRRs) and intracellular nucleotide-binding domain leucine-rich repeat receptors (NLRs) to initiate sophisticated downstream immune responses. Ubiquitination serves as one of the most important and prevalent posttranslational modifications (PTMs) to fine-tune plant immune responses. Over the last decade, remarkable progress has been made in delineating the critical roles of ubiquitination in plant immunity. In this review, we highlight recent advances in the understanding of ubiquitination in the modulation of plant immunity, with a particular focus on ubiquitination in the regulation of receptorsomes, and discuss how ubiquitination and other PTMs act in concert to ensure rapid, proper, and robust immune responses.

The Rice Malectin Regulates Plant Cell Death and Disease Resistance by Participating in Glycoprotein Quality Control.

In animals, malectin is well known to play an essential role in endoplasmic reticulum quality control (ERQC) by interacting with ribophorin I, one unit of the oligosaccharyltransferase (OST) complex. However, the functions of malectin in plants remain largely unknown. Here, we demonstrate the rice OsMLD1 is an ER- and Golgi-associated malectin protein and physically interacts with rice homolog of ribophorin I (OsRpn1), and its disruption leads to spontaneous lesion mimic lesions, enhanced disease resistance, and prolonged ER stress. In addition, there are many more N-glycosites and N-glycoproteins identified from the mld1 mutant than wildtype. Furthermore, OsSERK1 and OsSERK2, which have more N-glycosites in mld1, were demonstrated to interact with OsMLD1. OsMLD1 can suppress OsSERK1- or OsSERK2-induced cell death. Thus, OsMLD1 may play a similar role to its mammalian homologs in glycoprotein quality control, thereby regulating cell death and immunity of rice, which uncovers the function of malectin in plants.

A Phytophthora capsici RXLR effector targets and inhibits the central immune kinases to suppress plant immunity.

Receptor-like cytoplasmic kinase subfamily VII (RLCK-VII) proteins are the central immune kinases in plant pattern-recognition receptor (PRR) complexes, and they orchestrate a complex array of defense responses against bacterial and fungal pathogens. However, the role of RLCK-VII in plant-oomycete pathogen interactions has not been established. Phytophthora capsici is a notorious oomycete pathogen that infects many agriculturally important vegetables. Here, we report the identification of RXLR25, an RXLR effector that is required for the virulence of P. capsici. In planta expression of RXLR25 significantly enhanced plants' susceptibility to Phytophthora pathogens. Microbial pattern-induced immune activation in Arabidopsis was severely impaired by RXLR25. We further showed that RXLR25 interacts with RLCK-VII proteins. Using nine rlck-vii high-order mutants, we observed that RLCK-VII-6 and RLCK-VII-8 members are required for resistance to P. capsici. The RLCK-VII-6 members are specifically required for Phytophthora culture filtrate (CF)-induced immune responses. RXLR25 directly targets RLCK-VII proteins such as BIK1, PBL8, and PBL17 and inhibits pattern-induced phosphorylation of RLCK-VIIs to suppress downstream immune responses. This study identified a key virulence factor for P. capsici, and the results revealed the importance of RLCK-VII proteins in plant-oomycete interactions.

RNA Interference-Based Screen Reveals Concerted Functions of MEKK2 and CRCK3 in Plant Cell Death Regulation.

A wide variety of intrinsic and extrinsic cues lead to cell death with unclear mechanisms. The infertility of some death mutants often hurdles the classical suppressor screens for death regulators. We have developed a transient RNA interference (RNAi)-based screen using a virus-induced gene silencing approach to understand diverse cell death pathways in Arabidopsis (Arabidopsis thaliana). One death pathway is due to the depletion of a MAP kinase (MAPK) cascade, consisting of MAPK kinase kinase 1 (MEKK1), MKK1/2, and MPK4, which depends on a nucleotide-binding site Leu-rich repeat (NLR) protein SUMM2. Silencing of MEKK1 by virus-induced gene silencing resembles the mekk1 mutant with autoimmunity and defense activation. The RNAi-based screen toward Arabidopsis T-DNA insertion lines identified SUMM2, MEKK2, and Calmodulin-binding receptor-like cytoplasmic kinase 3 (CRCK3) to be vital regulators of RNAi MEKK1-induced cell death, consistent with the reports of their requirement in the mekk1-mkk1/2-mpk4 death pathway. Similar with MEKK2, overexpression of CRCK3 caused dosage- and SUMM2-dependent cell death, and the transcripts of CRCK3 were up-regulated in mekk1, mkk1/2, and mpk4 MEKK2-induced cell death depends on CRCK3. Interestingly, CRCK3-induced cell death also depends on MEKK2, consistent with the biochemical data that MEKK2 complexes with CRCK3. Furthermore, the kinase activity of CRCK3 is essential, whereas the kinase activity of MEKK2 is dispensable, for triggering cell death. Our studies suggest that MEKK2 and CRCK3 exert concerted functions in the control of NLR SUMM2 activation and MEKK2 may play a structural role, rather than function as a kinase, in regulating CRCK3 protein stability.

Comparison of the Distinct, Host-Specific Response of Three Solanaceae Hosts Induced by Phytophthora infestans.

Three Solanaceae hosts (TSHs), S. tuberosum, N. benthamiana and S. lycopersicum, represent the three major phylogenetic clades of Solanaceae plants infected by Phytophthora infestans, which causes late blight, one of the most devastating diseases seriously affecting crop production. However, details regarding how different Solanaceae hosts respond to P. infestans are lacking. Here, we conducted RNA-seq to analyze the transcriptomic data from the TSHs at 12 and 24 h post P. infestans inoculation to capture early expression effects. Macroscopic and microscopic observations showed faster infection processes in S. tuberosum than in N. benthamiana and S. lycopersicum under the same conditions. Analysis of the number of genes and their level of expression indicated that distinct response models were adopted by the TSHs in response to P. infestans. The host-specific infection process led to overlapping but distinct in GO terms and KEGG pathways enriched for differentially expressed genes; many were tightly linked to the immune response in the TSHs. S. tuberosum showed the fastest response and strongest accumulation of reactive oxygen species compared with N. benthamiana and S. lycopersicum, which also had similarities and differences in hormone regulation. Collectively, our study provides an important reference for a better understanding of late blight response mechanisms of different Solanaceae host interactions.

Proteolytic Processing of SERK3/BAK1 Regulates Plant Immunity, Development, and Cell Death.

Plants have evolved many receptor-like kinases (RLKs) to sense extrinsic and intrinsic cues. The signaling pathways mediated by multiple Leucine-rich repeat (LRR) RLK (LRR-RLK) receptors require ligand-induced receptor-coreceptor heterodimerization and transphosphorylation with BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1)/SOMATIC EMBRYOGENESIS RECEPTOR KINASES family LRR-RLKs. Here we reveal an additional layer of regulation of BAK1 via a Ca2+-dependent proteolytic cleavage process that is conserved in Arabidopsis (Arabidopsis thaliana), Nicotiana benthamiana, and Saccharomyces cerevisiae The proteolytic cleavage of BAK1 is intrinsically regulated in response to developmental cues and immune stimulation. The surface-exposed Asp (D287) residue of BAK1 is critical for its proteolytic cleavage and plays an essential role in BAK1-regulated plant immunity, growth hormone brassinosteroid-mediated responses, and cell death containment. BAK1D287A mutation impairs BAK1 phosphorylation on its substrate BOTRYTIS-INDUCED KINASE1 (BIK1), and its plasma membrane localization. Intriguingly, it aggravates BAK1 overexpression-triggered cell death independent of BIK1, suggesting that maintaining homeostasis of BAK1 through a proteolytic process is crucial to control plant growth and immunity. Our data reveal that in addition to layered transphosphorylation in the receptor complexes, the proteolytic cleavage is an important regulatory process for the proper functions of the shared coreceptor BAK1 in diverse cellular signaling pathways.

Differential Regulation of Two-Tiered Plant Immunity and Sexual Reproduction by ANXUR Receptor-Like Kinases.

Plants have evolved two tiers of immune receptors to detect infections: cell surface-resident pattern recognition receptors (PRRs) that sense microbial signatures and intracellular nucleotide binding domain leucine-rich repeat (NLR) proteins that recognize pathogen effectors. How PRRs and NLRs interconnect and activate the specific and overlapping plant immune responses remains elusive. A genetic screen for components controlling plant immunity identified ANXUR1 (ANX1), a malectin-like domain-containing receptor-like kinase, together with its homolog ANX2, as important negative regulators of both PRR- and NLR-mediated immunity in Arabidopsis thaliana ANX1 constitutively associates with the bacterial flagellin receptor FLAGELLIN-SENSING2 (FLS2) and its coreceptor BRI1-ASSOCIATED RECEPTOR KINASE1 (BAK1). Perception of flagellin by FLS2 promotes ANX1 association with BAK1, thereby interfering with FLS2-BAK1 complex formation to attenuate PRR signaling. In addition, ANX1 complexes with the NLR proteins RESISTANT TO PSEUDOMONAS SYRINGAE2 (RPS2) and RESISTANCE TO P. SYRINGAE PV MACULICOLA1. ANX1 promotes RPS2 degradation and attenuates RPS2-mediated cell death. Surprisingly, a mutation that affects ANX1 function in plant immunity does not disrupt its function in controlling pollen tube growth during fertilization. Our study thus reveals a molecular link between PRR and NLR protein complexes that both associate with cell surface-resident ANX1 and uncovers uncoupled functions of ANX1 and ANX2 during plant immunity and sexual reproduction.

Fuzhu jiangtang granules combined with metformin reduces insulin resistance in skeletal muscle of diabetic rats via PI3K/Akt signaling.

Context: Fuzhu Jiangtang Granules (FJG) are a traditional Chinese used in the treatment of diabetes mellitus. However, the antidiabetic mechanism of FJG is not clear. Objective: This study evaluates and determines the antidiabetic mechanism of FJG using a Zucker diabetic fatty (ZDF) rat model. Materials and methods: ZDF (fa/fa) rats were divided into four groups (n = 6): diabetes mellitus (DM), metformin (Met, 0.134 g/kg b.w./day), FJG (0.64 g/kg b.w./day), and combination (Com, 0.134 g/kg b.w./day of Met and 0.64 g/kg b.w./day of FJG). Six ZDF (fa/+) rats served as a normal control. After 6 weeks, biochemical parameters gene and protein expression were detected. Results: The FBG, bodyweight, triglyceride (TG), total cholesterol (TC), free fatty acid (FFA), insulin levels, and HOMA-IR were lower in the FJG than in the DM group (p < 0.05, p < 0.01). In an oral glucose tolerance test, the AUC in the FJG group was significantly lower (p < 0.01). The levels of superoxide dismutase and catalase were higher in the FJG than in the DM group (p < 0.01); the malondialdehyde content and TNF-α were significantly decreased in the FJG group (p < 0.01). FJG increased the mRNA expression of IR and GLUT4 significantly (p < 0.05, p < 0.01). The protein levels of IR, p-IRS1 tyr989, m-PI3Kp85, p-Akt and GLUT4 were increased in the FJG (p < 0.05, p < 0.01), but the protein levels of p-IRS1 ser1101/612/307 were significantly decreased in the JG group (p < 0.01). Discussion and conclusions: The antidiabetic mechanism of FJG may be related to regulation of the insulin-signaling pathway in skeletal muscle. These aspects require further research.

Effect of mulberry leaf (Folium Mori) on insulin resistance via IRS-1/PI3K/Glut-4 signalling pathway in type 2 diabetes mellitus rats.

CONTEXT: Folium Mori, the leaf of Morus alba L. (Moraceae), has been used in traditional Chinese medicine (TCM) for treating diabetes. However, it is unclear which components in the mulberry leaf are effective for the treatment of type 2 diabetes mellitus (T2DM). OBJECTIVE: To investigate the flavonoids and polyphenols in mulberry leaves and their antihyperglycemic and antihyperlipidemic effects in T2DM rats. MATERIALS AND METHODS: Male Sprague-Dawley rats were divided into five groups: normal control (NC), diabetic control (DBC), diabetic group with 0.3 mg/kg b.w./day rosiglitazone (RSG), diabetic group with 7 g/kg b.w./day TCM formula and diabetic group with 2 g/kg b.w./day Folium Mori extract (FME). After 4 weeks, the rats were sacrificed; biochemical parameters, gene and protein expression were measured. RESULTS: The FBG level was significantly lower in the FME group than in the DBC group (p < 0.05). In oral glucose tolerance test, the AUC was significantly lower in the FME group (p < 0.05). The HOMA-IR level was significantly decreased in the FME group (p < 0.05). FME decreased the total cholesterol (TC), triglyceride (TG) and low density lipoprotein (LDL) levels (p < 0.05). FME increased the mRNA and protein expression of IRS-1, PI3K p85α and Glut-4 increased significantly (p < 0.05). Histological analysis revealed amelioration of lipid accumulation following FME treatment. Additionally, immunohistochemical analysis displayed stronger staining of Glut-4 in the FME group compared to the DBC group. DISCUSSION AND CONCLUSION: FME could decrease the body weight, blood glucose, TG, TC and LDL levels, and improve insulin resistance. FME possessed significant antihyperglycemic and antihyperlipidemic activities via the IRS-1/PI3K/Glut-4 signalling pathway.

The dominant negative ARM domain uncovers multiple functions of PUB13 in Arabidopsis immunity, flowering, and senescence.

Regulating the intensity and duration of immune responses is crucial to combat infections without deleterious side effects. Arabidopsis FLS2, the receptor for bacterial flagellin, activates immune signalling by association with its partner BAK1. Upon flagellin (flg22) perception, the plant U-box E3 ubiquitin ligases PUB12 and PUB13 complex with FLS2 in a BAK1-dependent manner, and ubiquitinate FLS2 for protein degradation, thereby down-regulating flagellin signalling. Domain deletion analysis indicates that the ARM domain of PUB13 interacts with the FLS2-BAK1 complex and is phosphorylated by BAK1. Overexpression of the PUB13 ARM domain alone inhibits flg22-induced FLS2-PUB13 association and PUB12/13-mediated FLS2 ubiquitination and degradation in Arabidopsis, suggesting that ectopic expression of the ARM domain in planta generates a dominant negative effect via blocking the ubiquitination activity. Similar to the pub12pub13 double mutant, transgenic plants expressing the PUB13 ARM domain display enhanced immune responses compared with wild-type plants. Moreover, PUB13ARM transgenic plants and the pub12pub13 mutant are more sensitive to stress-induced leaf senescence accompanied by elevated expression of stress-induced senescence marker genes. The resemblance between PUB13ARM transgenic plants and the pub12pub13 mutant provides genetic evidence that ectopic expression of the PUB ARM domain serves as an alternative approach to dissect the overlapping functions of closely related PUB genes.

Synthesis and Biological Activity of Isoflavone Derivatives from Chickpea as Potent Anti-Diabetic Agents.

A set of novel isoflavone derivatives from chickpea were synthesized. The structures of derivatives were identified by proton nuclear magnetic resonance (¹H-NMR), carbon-13 ((13)C)-NMR and mass spectrometry (MS) spectral analyses. Their anti-diabetic activities were evaluated using an insulin-resistant (IR) HepG2 cell model. Additionally, the structure-activity relationships of these derivatives were briefly discussed. Compounds 1c, 2h, 3b, and 5 and genistein exhibited significant glucose consumption-enhancing effects in IR-HepG2 cells. In addition, the combinations of genistein, 2h, and 3b (combination 6) and of 3b, genistein, and 1c (combination 10) exhibited better anti-diabetic activity than the individual compounds. At the same dosage, there was no difference in effect between the combination 10 and the positive control (p > 0.05). Aditionally, we found the differences between the combination 10 and combination 6 for the protective effect of HUVEC (human umbilical vein endothelial cells) under high glucose concentration. The protective effects of combination 10 was stronger than combination 6, which suggested that combination 10 may have a better hypoglycemic activity in future studies. This study provides useful clues for the further design and discovery of anti-diabetic agents.

A Flexible Skin Bionic Thermally Comfortable Wearable for Machine Learning-Facilitated Ultrasensitive Sensing.

Tremendous popularity is observed for multifunctional flexible electronics with appealing applications in intelligent electronic skins, human-machine interfaces, and healthcare sensing. However, the reported sensing electronics, mostly can hardly provide ultrasensitive sensing sensitivity, wider sensing range, and robust cycling stability simultaneously, and are limited of efficient heat conduction out from the contacted skin interface after wearing flexible electronics on human skin to satisfy thermal comfort of human skin. Inspired from the ultrasensitive tactile perception microstructure (epidermis/spinosum/signal transmission) of human skin, a flexible comfortably wearable ultrasensitive electronics is hereby prepared from thermal conductive boron nitride nanosheets-incorporated polyurethane elastomer matrix with MXene nanosheets-coated surface microdomes as epidermis/spinosum layers assembled with interdigitated electrode as sensing signal transmission layer. It demonstrates appealing sensing performance with ultrasensitive sensitivity (≈288.95 kPa-1), up to 300 kPa sensing range, and up to 20 000 sensing cycles from obvious contact area variation between microdome microstructures and the contact electrode under external compression. Furthermore, the bioinspired electronics present advanced thermal management by timely efficient thermal dissipation out from the contacted skin surface to meet human skin thermal comfort with the incorporated thermal conductive boron nitride nanosheets. Thus, it is vitally promising in wearable artificial electronic skins, intelligent human-interactive sensing, and personal health management.

Metformin blocks BIK1-mediated CPK28 phosphorylation and enhances plant immunity.

INTRODUCTION: Metformin (MET), derived from Galega officinalis, stands as the primary first-line medication for the treatment of type 2 diabetes (T2D). Despite its well-documented benefits in mammalian cellular processes, its functions and underlying mechanisms in plants remain unclear. OBJECTIVES: This study aimed to elucidate MET's role in inducing plant immunity and investigate the associated mechanisms. METHODS: To investigate the impact of MET on enhancing plant immune responses, we conducted assays measuring defense gene expression, reactive oxygen species (ROS) accumulation, mitogen-activated protein kinase (MAPK) phosphorylation, and pathogen infection. Additionally, surface plasmon resonance (SPR) and microscale thermophoresis (MST) techniques were employed to identify MET targets. Protein-protein interactions were analyzed using a luciferase complementation assay and a co-immunoprecipitation assay. RESULTS: Our findings revealed that MET boosts plant disease resistance by activating MAPKs, upregulating the expression of downstream defense genes, and fortifying the ROS burst. CALCIUM-DEPENDENT PROTEIN KINASE 28 (CPK28) was identified as a target of MET. It inhibited the interaction between BOTRYTIS-INDUCED KINASE 1 (BIK1) and CPK28, blocking CPK28 threonine 76 (T76) transphosphorylation by BIK1, and alleviating the negative regulation of immune responses by CPK28. Moreover, MET enhanced disease resistance in tomato, pepper, and soybean plants. CONCLUSION: Collectively, our data suggest that MET enhances plant immunity by blocking BIK1-mediated CPK28 phosphorylation.

Research on the causal mechanism of a rock burst accident in a longwall roadway and its prevention measures.

Based on the disaster characteristics and the geo-conditions at the scene, in this study, the occurrence mechanism of a serious rock burst accident that occurred in the Tangshan Coal Mine, China, was analysed. Ground stress measurements showed that the mine is in a high ground stress area dominated by horizontal tectonic stress around 33 MPa. Laboratory testing revealed that the coal was a hard seam of 8.3 MPa over bedded by a thick and hard roof stratum with uniaxial compressive strength of 66 MPa. The calculation results indicated that the accident occurred in the roof rebounding area. It is proposed that the hard roof and the hard coal seam formed a seesaw structure around the working face. The vertical pressure relief caused the rib coal mass to lose its clamping forces from the roof and floor and rush into the roadway, resulting in a rock burst accident. Based on the causality mechanism of the rock burst disaster developed in this study, pertinent coal bump prevention measures have been undertaken in practice. Large-diameter boreholes were drilled to eliminate the pivot effect of the seam. Roof blasting was undertaken to prevent the roof from forming a seesaw plank. To summarize, a new causality mechanism for rock burst in coal mines under hard roof and hard seam geo-conditions was developed.