ABSTRACT
Small secreted peptides (SSPs) are essential for defense mechanisms in plant-microbe interactions, acting as danger-associated molecular patterns (DAMPs). Despite the first discovery of SSPs over three decades ago, only a limited number of SSP families, particularly within Solanaceae plants, have been identified due to inefficient approaches. This study employed comparative genomics screens with Solanaceae proteomes (tomato, tobacco, and pepper) to discover a novel SSP family, SolP. Bioinformatics analysis suggests that SolP may serve as an endogenous signal initiating the plant PTI response. Interestingly, SolP family members from tomato, tobacco, and pepper share an identical sequence (VTSNALALVNRFAD), named SlSolP12 (also referred to as NtSolP15 or CaSolP1). Biochemical and phenotypic analyses revealed that synthetic SlSolP12 peptide triggers multiple defense responses: ROS burst, MAPK activation, callose deposition, stomatal closure, and expression of immune defense genes. Furthermore, SlSolP12 enhances systemic resistance against Botrytis cinerea infection in tomato plants and interferes with classical peptides, flg22 and Systemin, which modulate the immune response. Remarkably, SolP12 activates ROS in diverse plant species, such as Arabidopsis thaliana, soybean, and rice, showing a broad spectrum of biological activities. This study provides valuable approaches for identifying endogenous SSPs and highlights SlSolP12 as a novel DAMP that could serve as a useful target for crop protection.
ABSTRACT
Agrobacterium-mediated transient expression is a flexible and efficient technique for introducing genes into plants, allowing for rapid and temporary gene expression. Agroinfiltration of Arabidopsis seedlings is a newly developed Agrobacterium-based transient expression system. The expression of target genes and the localization of relevant proteins can be observed within 3 days using this method. In this chapter, we present the detailed protocol for transient transformation in Arabidopsis thaliana seedlings utilizing vacuum infiltration of Agrobacterium. This procedure enables rapid and temporary gene expression by introducing exogenous DNA into Arabidopsis seedlings, particularly in easily accessible tissues such as cotyledons. This protocol provides a detailed description of experimental procedures, including Arabidopsis seedlings cultivation, the preparation of Agrobacterium suspensions, and subsequent steps leading to confocal microscope observation. Through this protocol, researchers can efficiently investigate gene function and subcellular localization in Arabidopsis cotyledons within 8 days in total.
Subject(s)
Arabidopsis , Seedlings , Arabidopsis/genetics , Arabidopsis/metabolism , Seedlings/genetics , Seedlings/metabolism , Seedlings/growth & development , Vacuum , Cotyledon/genetics , Cotyledon/metabolism , Transformation, Genetic , Gene Expression , Plants, Genetically Modified/genetics , Agrobacterium/genetics , Gene Expression Regulation, Plant , Microscopy, ConfocalABSTRACT
High-pressure freezing/freeze substitution has been used to preserve biological samples for ultrastructure study instead of chemical fixation. For most plant samples, the water content is too high and cannot be properly preserved during cryofixation. Additionally, the cell wall is a barrier that prevents the substitution of water with the resin. In this chapter, we will discuss modified high-pressure freezing and subsequent processing protocols based on our routinely used methodology for examining Arabidopsis seeds in transmission electron microscopy and electron tomography.
Subject(s)
Arabidopsis , Electron Microscope Tomography , Seeds , Seeds/ultrastructure , Electron Microscope Tomography/methods , Arabidopsis/ultrastructure , Freezing , Cold Temperature , Pressure , Microscopy, Electron, Transmission/methods , Cryopreservation/methods , Freeze Substitution/methodsABSTRACT
Aim: In China, with the increase of life expectancy and the decrease of fertility rate, the aging problem has become increasingly prominent, and the physical problems of the older people over 70 years are the key and difficult problems. Method: Based on the interactive logic between the aging problem and the older people health, in the study, a questionnaire survey and a nationwide physical fitness test were carried out on the older people over 70, to divide into different age groups (70-74 years old, 75-79 years old, 80-84 years old, 85 years old and older) and different genders. There were 8,400 valid samples, and 1,050 persons in each group. One-way ANOVA was used to compare the differences among groups of different ages, and a broken line chart was drawn to discuss the aging characteristics of various physical indexes of the older people over 70 in China. Result: (1) Body morphology: male waist circumference, male waist-to-height ratio and female BMI showed a gradual downward trend with the increase of age; (2) Physiological function: male and female vital capacity showed a decreasing trend with the increase of age, while female pulse pressure showed a gradual upward trend. (3) Physical quality: the indicators of male and female muscle strength, flexibility quality, aerobic endurance and balance showed a downward trend with the increase of age. Conclusion: Vital capacity, flexibility quality, muscle strength, aerobic endurance, balance ability and so on, decreased significantly with the growth of age. 80 years old is the inflection point of the rapid decline of various indicators. Blood pressure, silent pulse, BMI, waist-to-hip ratio, waist-to-height ratio and other indicators did not change regularly with age. Indicators such as blood pressure, BMI, waist-to-hip ratio and waist-to-height ratio were in the high-risk range of metabolic diseases and cardiovascular and cerebrovascular diseases. The study conducted physical fitness test on the older people over 70 years old in 7 geographical regions of China, which is the first nationwide physical fitness test for the older people, which is an extension and expansion of the national physical fitness monitoring system, and also shows that the test indicators involved in the "Health fitness scale" are simple and feasible. And the study added a series of test data over 70 years old, which is the basis for scientific and reasonable formulation of physical fitness evaluation standards for the older people, and is of great significance for improving the national physical fitness database and grasping the dynamic changes of national physical health status, and providing data support for scientific guidance of physical exercise for the older people.
Subject(s)
Aging , Physical Fitness , Humans , Aged , Male , China/epidemiology , Female , Aged, 80 and over , Physical Fitness/physiology , Aging/physiology , Surveys and Questionnaires , Body Mass Index , Muscle Strength/physiologyABSTRACT
The CLE (CLAVATA3/Embryo Surrounding Region-related) family, a group of peptides with hormone-like features, plays a pivotal role in plant growth, development, and adaptation to stress. Through homology-based blast analysis of 32 Arabidopsis thaliana CLE peptide sequences, we have identified 5, 14, and 10 CLE family members in Nicotiana tabacum, Capsicum annuum, and Solanum melongena, respectively. Chemical synthesis and functional assays of the peptides led to the discovery that NtCLE3 substantially enhances the drought resistance of these three Solanaceae crops. Our transcriptome, RT-qPCR, and antioxidant enzyme activity data showed that NtCLE3 increased antioxidant capacity and ABA synthesis in tobacco. Moreover, the recombinant protein RPNtCLE3, composed of 6*NtCLE3, preserved the capacity to foster drought resilience and proved to be a promising drought resistance regulator, which presents a more favorable alternative for field applications compared to ABA which degrades rapidly under sunlight exposure. This research unveils the prospective utility of NtCLE3 in enhancing drought tolerance in Solanaceae crops and provides new ideas for the development of novel bioregulators aimed at mitigating drought stress.
ABSTRACT
Genetic engineering using negative regulators of plant immunity has the potential to provide a huge impetus in agricultural biotechnology to achieve a higher degree of disease resistance without reducing yield. Type 2C protein phosphatases (PP2Cs) represent the largest group of protein phosphatases in plants, with a high potential for negative regulatory functions by blocking the transmission of defence signals through dephosphorylation. Here, we established a PP2C functional protoplast screen using pFRK1::luciferase as a reporter and found that 14 of 56 PP2Cs significantly inhibited the immune response induced by flg22. To verify the reliability of the system, a previously reported MAPK3/4/6-interacting protein phosphatase, PP2C5, was used; it was confirmed to be a negative regulator of PAMP-triggered immunity (PTI). We further identified PP2C15 as an interacting partner of BRI1-associated receptor kinase 1 (BAK1), which is the most well-known co-receptor of plasma membrane-localized pattern recognition receptors (PRRs), and a central component of PTI. PP2C15 dephosphorylates BAK1 and negatively regulates BAK1-mediated PTI responses such as MAPK3/4/6 activation, defence gene expression, reactive oxygen species bursts, stomatal immunity, callose deposition, and pathogen resistance. Although plant growth and 1000-seed weight of pp2c15 mutants were reduced compared to those of wild-type plants, pp2c5 mutants did not show any adverse effects. Thus, our findings strengthen the understanding of the mechanism by which PP2C family members negatively regulate plant immunity at multiple levels and indicate a possible approach to enhance plant resistance by eliminating specific PP2Cs without affecting plant growth and yield.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Arabidopsis Proteins/metabolism , Reproducibility of Results , Phosphoprotein Phosphatases/genetics , Phosphoprotein Phosphatases/metabolism , Phosphoprotein Phosphatases/pharmacology , Plant Immunity/physiology , Gene Expression Regulation, Plant , Protein Kinases/genetics , Protein Kinases/metabolismABSTRACT
Gate-controlled ionic intercalation in the van der Waals gap of 2D layered materials can induce novel phases and unlock new properties. However, this strategy is often unsuitable for densely packed 2D non-layered materials. The non-layered rhombohedral Cr2S3 is an intrinsic heterodimensional superlattice with alternating layers of 2D CrS2 and 0D Cr1/3. Here an innovative chemical vapor deposition method is reported, utilizing strategically modified metal precursors to initiate entirely new seed layers, yields ultrathin inclined-standing grown 2D Cr2S3 nanosheets with edge instead of face contact with substrate surfaces, enabling rapid all-dry transfer to other substrates while ensuring high crystal quality. The unconventional ordered vacancy channels within the 0D Cr1/3 layers, as revealed by cross-sectional scanning transmission electron microscope, permitting the insertion of Li+ ions. An unprecedented metal-insulator transition, with a resistance modulation of up to six orders of magnitude at 300 K, is observed in Cr2S3-based ionic field-effect transistors. Theoretical calculations corroborate the metallization induced by Li-ion intercalation. This work sheds light on the understanding of growth mechanism, structure-property correlation and highlights the diverse potential applications of 2D non-layered Cr2S3 superlattice.
ABSTRACT
PAMP-induced secreted peptide (PIP), one of the small post-translationally modified peptides (PTMPs), plays a crucial role in plant development and stress tolerance. However, little is known about functional divergence among this peptide family. Here, we studied the evolution of the PIP family in 23 plant species (10 monocotyledons and 13 dicotyledons from 7 families) and their functional divergence in Arabidopsis. A total of 128 putative PIP precursors were identified and classified into two subfamilies through phylogenetic analysis. Functional studies on AtPIP1 which represents Clade I family and AtPIP2 which represents Clade II family have shown that AtPIP2 displayed stronger immunity induction activity but weaker root growth inhibition than AtPIP1 in Arabidopsis. Transcriptome analysis of Arabidopsis seedlings treated with AtPIP1 and AtPIP2 showed that differential genes for both polypeptides were significantly enriched in similar plant defense pathways. However, Co-expression and Protein-protein interaction (PPI) analysis showed that the functions of AtprePIP2 co-expressed genes were more enriched in plant defense pathways than AtprePIP1. Molecular docking results show that AtPIP1 binds to RLK7 receptor with a more stable free energy and less binding area than AtPIP2, while hydrogen bond transfer occurs at the SGP motif position. The above results suggest that the PIP family have undergone functional divergence during evolution. Collectively, this work illustrates the relationship between PIP structure and function using Arabidopsis PIP as an example, and provides new insights into the current understanding between growth inhibition and immune responses which may be correlated but not fully coupled.
ABSTRACT
Membrane protein homeostasis is fine-tuned by the cellular pathways for vacuolar degradation and recycling, which ultimately facilitate plant growth and cell-environment interactions. The endosomal sorting complex required for transport (ESCRT) machinery plays important roles in regulating intraluminal vesicle (ILV) formation and membrane protein sorting to vacuoles. We previously showed that the plant-specific ESCRT component FYVE DOMAIN PROTEIN REQUIRED FOR ENDOSOMAL SORTING1 (FREE1) performs multiple functions in plants, although the underlying mechanisms remain elusive. In this study, we performed a suppressor screen of the FREE1-RNAi mutant and identified and characterized 2 suppressor of free1 (sof) mutants in Arabidopsis (Arabidopsis thaliana). These mutants, sof10 and sof641, result in a premature stop codon or a missense mutation in AT5G10370, respectively. This gene was named DEAH and RING domain-containing protein as FREE1 suppressor 1 (DRIF1). DRIF1 has a homologous gene, DRIF2, in the Arabidopsis genome with 95% identity to DRIF1. The embryos of drif1 drif2 mutants arrested at the globular stage and formed enlarged multivesicular bodies (MVBs) with an increased number of ILVs. DRIF1 is a membrane-associated protein that coordinates with retromer component sorting nexin 1 to regulate PIN-FORMED2 recycling to the plasma membrane. Altogether, our data demonstrate that DRIF1 is a unique retromer interactor that orchestrates FREE1-mediated ILV formation of MVBs and vacuolar sorting of membrane proteins for degradation in plants.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Sorting Nexins/genetics , Sorting Nexins/metabolism , Arabidopsis Proteins/metabolism , Plant Proteins/metabolism , Endosomal Sorting Complexes Required for Transport/metabolism , Proteostasis , Protein Transport/genetics , Plants/metabolism , Vesicular Transport Proteins/genetics , Vesicular Transport Proteins/metabolismABSTRACT
The endomembrane system consists of various membrane-bound organelles including the endoplasmic reticulum (ER), Golgi apparatus, trans-Golgi network (TGN), endosomes, and the lysosome/vacuole. Membrane trafficking between distinct compartments is mainly achieved by vesicular transport. As the endomembrane compartments and the machineries regulating the membrane trafficking are largely conserved across all eukaryotes, our current knowledge on organelle biogenesis and endomembrane trafficking in plants has mainly been shaped by corresponding studies in mammals and yeast. However, unique perspectives have emerged from plant cell biology research through the characterization of plant-specific regulators as well as the development and application of the state-of-the-art microscopical techniques. In this review, we summarize our current knowledge on the plant endomembrane system, with a focus on several distinct pathways: ER-to-Golgi transport, protein sorting at the TGN, endosomal sorting on multivesicular bodies, vacuolar trafficking/vacuole biogenesis, and the autophagy pathway. We also give an update on advanced imaging techniques for the plant cell biology research.
Subject(s)
Endosomes , Plants , Plants/metabolism , Endosomes/metabolism , Vacuoles/metabolism , Multivesicular Bodies/metabolism , Protein Transport , Golgi Apparatus/metabolism , trans-Golgi Network/metabolismABSTRACT
Pollen tubes have dynamic tubular vacuoles. Functional loss of AP-3, a regulator of one vacuolar trafficking route, reduces pollen tube growth. However, the role of canonical Rab5 GTPases that are responsible for two other vacuolar trafficking routes in Arabidopsis pollen tubes is obscure. By using genomic editing, confocal microscopy, pollen tube growth assays, and transmission electron microscopy, we demonstrate that functional loss of canonical Rab5s in Arabidopsis, RHA1 and ARA7, causes the failure of pollen tubes to grow through style and thus impairs male transmission. Functional loss of canonical Rab5s compromises vacuolar trafficking of tonoplast proteins, vacuolar biogenesis, and turgor regulation. However, rha1;ara7 pollen tubes are comparable to those of wild-type in growing through narrow passages by microfluidic assays. We demonstrate that functional loss of canonical Rab5s compromises endocytic and secretory trafficking at the plasma membrane (PM), whereas the targeting of PM-associated ATPases is largely unaffected. Despite that, rha1;ara7 pollen tubes contain a reduced cytosolic pH and disrupted actin microfilaments, correlating with the mis-targeting of vacuolar ATPases (VHA). These results imply a key role of vacuoles in maintaining cytoplasmic proton homeostasis and in pollen tube penetrative growth through style.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Pollen Tube , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , GTP Phosphohydrolases/metabolism , Adenosine Triphosphatases/metabolismABSTRACT
Arabidopsis plastid antiporters KEA1 and KEA2 are critical for plastid development, photosynthetic efficiency, and plant development. Here, we show that KEA1 and KEA2 are involved in vacuolar protein trafficking. Genetic analyses found that the kea1 kea2 mutants had short siliques, small seeds, and short seedlings. Molecular and biochemical assays showed that seed storage proteins were missorted out of the cell and the precursor proteins were accumulated in kea1 kea2. Protein storage vacuoles (PSVs) were smaller in kea1 kea2. Further analyses showed that endosomal trafficking in kea1 kea2 was compromised. Vacuolar sorting receptor 1 (VSR1) subcellular localizations, VSR-cargo interactions, and p24 distribution on the endoplasmic reticulum (ER) and Golgi apparatus were affected in kea1 kea2. Moreover, plastid stromule growth was reduced and plastid association with the endomembrane compartments was disrupted in kea1 kea2. Stromule growth was regulated by the cellular pH and K+ homeostasis maintained by KEA1 and KEA2. The organellar pH along the trafficking pathway was altered in kea1 kea2. Overall, KEA1 and KEA2 regulate vacuolar trafficking by controlling the function of plastid stromules via adjusting pH and K+ homeostasis.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Antiporters/genetics , Antiporters/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Vacuoles/metabolism , Plastids/metabolism , Cations/metabolism , Protein TransportABSTRACT
The study of endomembrane trafficking is crucial for understanding how cells and whole organisms function. Moreover, there is a special interest in investigating endomembrane trafficking in plants, given its role in transport and accumulation of seed storage proteins and in secretion of cell wall material, arguably the two most essential commodities obtained from crops. The mechanisms of anterograde transport in the biosynthetic and endocytic pathways of plants have been thoroughly discussed in recent reviews, but, comparatively, retrograde trafficking pathways have received less attention. Retrograde trafficking is essential to recover membranes, retrieve proteins that have escaped from their intended localization, maintain homeostasis in maturing compartments, and recycle trafficking machinery for its reuse in anterograde transport reactions. Here, we review the current understanding on retrograde trafficking pathways in the endomembrane system of plants, discussing their integration with anterograde transport routes, describing conserved and plant-specific retrieval mechanisms at play, highlighting contentious issues and identifying open questions for future research.
Subject(s)
Plants , Biological Transport , Plants/metabolism , Protein TransportABSTRACT
The energy sensor AMP-activated protein kinase (AMPK) can activate autophagy when cellular energy production becomes compromised. However, the degree to which nutrient sensing impinges on the autophagosome closure remains unknown. Here, we provide the mechanism underlying a plant unique protein FREE1, upon autophagy-induced SnRK1α1-mediated phosphorylation, functions as a linkage between ATG conjugation system and ESCRT machinery to regulate the autophagosome closure upon nutrient deprivation. Using high-resolution microscopy, 3D-electron tomography, and protease protection assay, we showed that unclosed autophagosomes accumulated in free1 mutants. Proteomic, cellular and biochemical analysis revealed the mechanistic connection between FREE1 and the ATG conjugation system/ESCRT-III complex in regulating autophagosome closure. Mass spectrometry analysis showed that the evolutionary conserved plant energy sensor SnRK1α1 phosphorylates FREE1 and recruits it to the autophagosomes to promote closure. Mutagenesis of the phosphorylation site on FREE1 caused the autophagosome closure failure. Our findings unveil how cellular energy sensing pathways regulate autophagosome closure to maintain cellular homeostasis.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Autophagosomes , Vesicular Transport Proteins , Arabidopsis/growth & development , Arabidopsis/metabolism , Endosomal Sorting Complexes Required for Transport/metabolism , Vesicular Transport Proteins/chemistry , Vesicular Transport Proteins/metabolism , Amino Acid Motifs , Arabidopsis Proteins/chemistry , Arabidopsis Proteins/metabolism , Protein Serine-Threonine Kinases/metabolismABSTRACT
The retromer is a heteromeric protein complex that localizes to endosomal membranes and drives the formation of endosomal tubules that recycle membrane protein cargoes. In plants, the retromer plays essential and canonical functions in regulating the transport of vacuolar storage proteins and the recycle of endocytosed plasma membrane proteins (PM); however, the mechanisms underlying the regulation of assembly, protein stability, and membrane recruitment of the plant retromer complex remain to be elucidated. In this study, we identify a plant-unique endosomal regulator termed BLISTER (BLI), which colocalizes and associates with the retromer complex by interacting with the retromer core subunits VPS35 and VPS29. Depletion of BLI perturbs the assembly and membrane recruitment of the retromer core VPS26-VPS35-VPS29 trimer. Consequently, depletion of BLI disrupts retromer-regulated endosomal trafficking function, including transport of soluble vacuolar proteins and recycling of endocytosed PIN-FORMED (PIN) proteins from the endosomes back to the PM. Moreover, genetic analysis in Arabidopsis thaliana mutants reveals BLI and core retromer interact genetically in the regulation of endosomal trafficking. Taken together, we identified BLI as a plant-specific endosomal regulator, which functions in retromer pathway to modulate the recycling of endocytosed PM proteins and the trafficking of soluble vacuolar cargoes.
Subject(s)
Arabidopsis , Plant Proteins , Plant Proteins/genetics , Plant Proteins/metabolism , Protein Transport , Endosomes/metabolism , Vacuoles/metabolism , Cell Membrane/metabolism , Membrane Proteins/genetics , Membrane Proteins/metabolism , Arabidopsis/metabolism , Sorting Nexins/metabolismABSTRACT
Computed tomography (CT) is widely used in clinical medicine, and low-dose CT (LDCT) has become popular to reduce potential patient harm during CT acquisition. However, LDCT aggravates the problem of noise and artifacts in CT images, increasing diagnosis difficulty. Through deep learning, denoising CT images by artificial neural network has aroused great interest for medical imaging and has been hugely successful. We propose a framework to achieve excellent LDCT noise reduction using independent operation search cells, inspired by neural architecture search, and introduce the Laplacian to further improve image quality. Employing patch-based training, the proposed method can effectively eliminate CT image noise while retaining the original structures and details, hence significantly improving diagnosis efficiency and promoting LDCT clinical applications.
Subject(s)
Neural Networks, Computer , Tomography, X-Ray Computed , Humans , Signal-To-Noise Ratio , Radiation Dosage , Tomography, X-Ray Computed/methods , ArtifactsABSTRACT
Objective@#To explore the correlation between different nutritional status and depressive symptoms among adolescents, so as to provide a theoretical basis for targeted improvement of nutritional status and depressive symptoms in adolescents.@*Methods@#A total of 8 102 adolescents aged 12-17 years in Shanghai, Urumqi, Changsha and Kunming were selected by random cluster sampling. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression Scale(CES-D). Height and weight were measured. Kruskal Wallis H test, Chi square test and ordinal Logistic regression were used to analyze the relationship between nutritional status and depressive symptoms in adolescents.@*Results@#The overall detection rate of depressive symptoms in adolescents was 25.6%, with girls (30.1%) higher than that of boys (21.1%) ( χ 2=87.60, P <0.01). There were statistically significant differences in the scores of depressive symptoms among girls with different nutritional status ( Z =8.34, P <0.05). The detectable rate of depressive symptoms increased with BMI among girls( χ 2 trend =6.04, P <0.05). After controlling for confounding factors, ordinal Logistic regression showed that the obese girls had higher risks in depressive symptoms detection compared with normal weight girls ( OR=1.45, 95%CI=1.10-1.91, P <0.05).@*Conclusion@#The nutritional status of girls is better than boys, but the prevalence of depressive symptoms is higher than boys. The risk of depressive symptoms in girls increases with BMI.