Quantitative Extracellular Matrix Proteomics Suggests Cell Wall Reprogramming in Host-Specific Immunity During Vascular Wilt Caused by Fusarium oxysporum in Chickpea

Proteo-metabolomic Dissection of Extracellular Matrix Reveals Alterations in Cell Wall Integrity and Calcium Signaling Governs Wall-Associated Susceptibility during Stem Rot Disease in Jute

The plant surveillance system confers specificity to disease and immune states by activating distinct molecular pathways linked to cellular functionality. The extracellular matrix (ECM), a preformed passive barrier, is dynamically remodeled at sites of interaction with pathogenic microbes. Stem rot, caused by Macrophomina phaseolina, adversely affects fiber production in jute. However, how wall related susceptibility affects the ECM proteome and metabolome remains undetermined in bast fiber crops. Here, stem rot responsive quantitative temporal ECM proteome and metabolome were developed in jute upon M. phaseolina infection. Morpho-histological examination revealed that leaf shredding was accompanied by reactive oxygen species production in patho-stressed jute. Electron microscopy showed disease progression and ECM architecture remodeling due to necrosis in the later phase of fungal attack. Using isobaric tags for relative and absolute quantitative proteomics and liquid chromatography-tandem mass spectrometry, we identified 415 disease-responsive proteins involved in wall integrity, acidification, proteostasis, hydration, and redox homeostasis. The disease-related correlation network identified functional hubs centered on α-galactosidase, pectinesterase, and thaumatin. Gas chromatography-mass spectrometry analysis pointed toward enrichment of disease-responsive metabolites associated with the glutathione pathway, TCA cycle, and cutin, suberin, and wax metabolism. Data demonstrated that wall-degrading enzymes, structural carbohydrates, and calcium signaling govern rot responsive wall-susceptibility. Proteomics data were deposited in Pride (PXD046937; PXD046939).

Proteomic signatures uncover phenotypic plasticity of susceptible and resistant genotypes by wall remodelers in rice blast

Molecular communication between macromolecules dictates extracellular matrix (ECM) dynamics during pathogen recognition and disease development. Extensive research has shed light on how plant immune components are activated, regulated and function in response to pathogen attack. However, two key questions remain largely unresolved: (i) how does ECM dynamics govern susceptibility and disease resistance, (ii) what are the components that underpin these phenomena? Rice blast, caused by Magnaporthe oryzae adversely affects rice productivity. To understand ECM regulated genotype-phenotype plasticity in blast disease, we temporally profiled two contrasting rice genotypes in disease and immune state. Morpho-histological, biochemical and electron microscopy analyses revealed that increased necrotic lesions accompanied by electrolyte leakage governs disease state. Wall carbohydrate quantification showed changes in pectin level was more significant in blast susceptible compared to blast resistant cultivar. Temporally resolved quantitative disease- and immune-responsive ECM proteomes identified 308 and 334 proteins, respectively involved in wall remodelling and integrity, signalling and disease/immune response. Pairwise comparisons between time and treatment, messenger ribonucleic acid expression, diseasome and immunome networks revealed novel blast-related functional modules. Data demonstrated accumulation of α-galactosidase and phosphatase were associated with disease state, while reactive oxygen species, induction of Lysin motif proteins, CAZymes and extracellular Ca-receptor protein govern immune state.

Combining extracellular matrix proteome and phosphoproteome of chickpea and meta-analysis reveal novel proteoforms and evolutionary significance of clade-specific wall-associated events in plant

Extracellular matrix (ECM) plays central roles in cell architecture, innate defense and cell wall integrity (CWI) signaling. During transition to multicellularity, modular domain structures of ECM proteins and proteoforms have evolved due to continuous adaptation across taxonomic clades under different ecological niche. Although this incredible diversity has to some extent been investigated at protein level, extracellular phosphorylation events and molecular evolution of ECM proteoform families remains unexplored. We developed matrisome proteoform atlas in a grain legume, chickpea and performed meta-analyses of 74 plant matrisomes. MS/MS analysis identified 1,424 proteins and 315 phosphoproteins involved in diverse functions. Cross-species ECM protein network identified proteoforms associated with CWI maintenance system. Phylogenetic characterization of eighteen matrix protein families highlighted the role of taxon-specific paralogs and orthologs. Novel information was acquired on gene expansion and loss, co-divergence, sub functionalization and neofunctionalization during evolution. Modular networks of matrix protein families and hub proteins showed higher diversity across taxonomic clades than among organs. Furthermore, protein families differ in nonsynonymous to synonymous substitution rates. Our study pointed towards the matrix proteoform functionality, sequence divergence variation, interactions between wall remodelers and molecular evolution using a phylogenetic framework. This is the first report on comprehensive matrisome proteoform network illustrating presence of CWI signaling proteins in land plants.

Defence response in plants and animals against a common fungal pathogen, Fusarium oxysporum

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Fusarium oxysporum species complex (FOSC) is considered one of the most devastating plant pathogen.

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FOSC is an emerging pathogen of immunocompromised individuals.

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Mycotoxins produced by FOSC predisposes the host to other pathogens.

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Comparative immune reactions in plant and invertebrate show that several antimicrobial peptides (AMPs) and secondary metabolites maybe used as control against Fusarium infection.

Plant pathogens emerging as threat to human and animal health has been a matter of concern within the scientific community. Fusarium oxysporum, predominantly a phytopathogen, can infect both plants and animals. As a plant pathogen, F. oxysporum is one of the most economically damaging pathogen. In humans, F. oxysporum can infect immunocompromised individuals and is increasingly being considered as a problematic pathogen. Mycotoxins produced by F. oxysporum supress the innate immune pathways in both plants and animals. Hence, F. oxysporum is the perfect example for studying similarities and differences between defence strategies adopted by plants and animals. In this review we will discuss the innate immune response of plant and animal hosts for protecting against F. oxysporum infection. Such studies will be helpful for identifying genes, protein and metabolites with antifungal properties suitable for protecting humans.

Phenothiazinium Photosensitizers Associated with Silver Nanoparticles in Enhancement of Antimicrobial Photodynamic Therapy

Antimicrobial photodynamic therapy (APDT) and silver nanoparticles (AgNPs) are known as promising alternatives for the control of microorganisms. This study aims to evaluate the antifungal activity of APDT, particularly by using the association of low concentrations of phenothiazinium photosensitizers (PS) methylene blue (MB), new methylene blue N (NMBN), and new methylene blue N Zinc (NMBN-Zn) in association with biosynthesized AgNPs. The AgNPs were characterized by UV-Vis spectrophotometry, transmission electron microscopy, and the dynamic light scattering method. The minimum inhibitory concentration of compounds in APDT against Candida albicans and Fusarium keratoplasticum was obtained and the Fractional Inhibitory Concentration Index determined the antifungal effect. The toxicity of compounds and associations in APDT were evaluated in Galleria mellonella. The AgNPs presented a surface plasmon band peak at 420 nm, hydrodynamic diameter of 86.72 nm, and zeta potential of -28.6 mV. AgNPs-PS showed a wider and displaced plasmon band peak due to PS ligands on the surface and decreased zeta potential. AgNPs-NMBN and AgNPs-NMBN-Zn associations presented synergistic effect in APDT with 15 J cm-2 against both fungi and did not show toxicity to G. mellonella. Hence, the enhancement of antifungal activity with low concentrations of compounds and absence of toxicity makes APDT with AgNPs-PS a promising therapeutic alternative for fungal infections.

Grapevine-Downy Mildew Rendezvous: Proteome Analysis of the First Hours of an Incompatible Interaction

Grapevine is one of the most relevant crops in the world being used for economically important products such as wine. However, relevant grapevine cultivars are heavily affected by diseases such as the downy mildew disease caused by Plasmopara viticola. Improvements on grapevine resistance are made mainly by breeding techniques where resistance traits are introgressed into cultivars with desired grape characteristics. However, there is still a lack of knowledge on how resistant or tolerant cultivars tackle the P. viticola pathogen. In this study, using a shotgun proteomics LC-MS/MS approach, we unravel the protein modulation of a highly tolerant grapevine cultivar, Vitis vinifera “Regent”, in the first hours post inoculation (hpi) with P. viticola. At 6 hpi, proteins related to defense and to response to stimuli are negatively modulated while at 12 hpi there is an accumulation of proteins belonging to both categories. The co-occurrence of indicators of effector-triggered susceptibility (ETS) and effector-triggered immunity (ETI) is detected at both time-points, showing that these defense processes present high plasticity. The results obtained in this study unravel the tolerant grapevine defense strategy towards P. viticola and may provide valuable insights on resistance associated candidates and mechanisms, which may play an important role in the definition of new strategies for breeding approaches.

Recognition Pattern, Functional Mechanism and Application of Chitin and Chitosan Oligosaccharides in Sustainable Agriculture

Background:

Application of chitin attracts much attention in the past decades as the second abundant polysaccharides in the world after cellulose. Chitin oligosaccharides (CTOS) and its deacetylated derivative chitosan oligosaccharides (COS) were shown great potentiality in agriculture by enhancing plant resistance to abiotic or biotic stresses, promoting plant growth and yield, improving fruits quality and storage, etc. Those applications have already served huge economic and social benefits for many years. However, the recognition mode and functional mechanism of CTOS and COS on plants have gradually revealed just in recent years.

Objective:

Recognition pattern and functional mechanism of CTOS and COS in plant together with application status of COS in agricultural production will be well described in this review. By which we wish to promote further development and application of CTOS and COS–related products in the field.

Chitosan-triggered immunity to Fusarium in chickpea is associated with changes in the plant extracellular matrix architecture, stomatal closure and remodeling of the plant metabolome and proteome

Pathogen-/microbe-associated molecular patterns (PAMPs/MAMPs) initiate complex defense responses by reorganizing the biomolecular dynamics of the host cellular machinery. The extracellular matrix (ECM) acts as a physical scaffold that prevents recognition and entry of phytopathogens, while guard cells perceive and integrate signals metabolically. Although chitosan is a known MAMP implicated in plant defense, the precise mechanism of chitosan-triggered immunity (CTI) remains unknown. Here, we show how chitosan imparts immunity against fungal disease. Morpho-histological examination revealed stomatal closure accompanied by reductions in stomatal conductance and transpiration rate as early responses in chitosan-treated seedlings upon vascular fusariosis. Electron microscopy and Raman spectroscopy showed ECM fortification leading to oligosaccharide signaling, as documented by increased galactose, pectin and associated secondary metabolites. Multiomics approach using quantitative ECM proteomics and metabolomics identified 325 chitosan-triggered immune-responsive proteins (CTIRPs), notably novel ECM structural proteins, LYM2 and receptor-like kinases, and 65 chitosan-triggered immune-responsive metabolites (CTIRMs), including sugars, sugar alcohols, fatty alcohols, organic and amino acids. Identified proteins and metabolites are linked to reactive oxygen species (ROS) production, stomatal movement, root nodule development and root architecture coupled with oligosaccharide signaling that leads to Fusarium resistance. The cumulative data demonstrate that ROS, NO and eATP govern CTI, in addition to induction of PR proteins, CAZymes and PAL activities, besides accumulation of phenolic compounds downstream of CTI. The immune-related correlation network identified functional hubs in the CTI pathway. Altogether, these shifts led to the discovery of chitosan-responsive networks that cause significant ECM and guard cell remodeling, and translate ECM cues into cell fate decisions during fusariosis.

Extracellular Matrix Proteome: Isolation of ECM Proteins for Proteomics Studies

Understanding molecular mechanisms and cellular metabolism in varied plant processes necessitates knowledge of the expressed proteins and their subcellular distribution. Spatial partitioning of organelles generates an enclosed milieu for physiochemical reactions designed and tightly linked to a specific organelle function. Of which, extracellular matrix (ECM)/cell wall (CW) is a dynamic and chemically active compartment. The ECM proteins are organized into complex structural and functional networks involved in several metabolic processes, including carbon and nitrogen metabolism. Organellar proteomics aim for comprehensive identification of resident proteins that rely on the isolation of highly purified organelle free from contamination by other intracellular components. Extraction and isolation of plant ECM proteins features key caveats due to the lack of adjoining membrane, the presence of a polysaccharide-protein network that traps contaminants, and the existence of high phenolic content. Furthermore, due to diverse biochemical forces, including labile, weakly bound and strongly bound protein in the protein-polysaccharide matrix different elution procedures are required to enrich ECM proteins. Here, we describe a method that allows efficient fractionation of plant ECM, extraction of ECM proteins and protein profiling from variety of crop plants, including rice, chickpea and potato. This method can easily be adapted to other plant species for varied experimental conditions.