scholarly journals Host Cell Wall Damage during Pathogen Infection: Mechanisms of Perception and Role in Plant-Pathogen Interactions

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 399
Author(s):  
Riccardo Lorrai ◽  
Simone Ferrari
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Complex Structure ◽  
Host Cell Wall ◽  
Infection Mechanisms ◽  
Phytopathogenic Microorganisms ◽  
Plant Pathogen Interactions ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns ◽  
Fine Tune

The plant cell wall (CW) is a complex structure that acts as a mechanical barrier, restricting the access to most microbes. Phytopathogenic microorganisms can deploy an arsenal of CW-degrading enzymes (CWDEs) that are required for virulence. In turn, plants have evolved proteins able to inhibit the activity of specific microbial CWDEs, reducing CW damage and favoring the accumulation of CW-derived fragments that act as damage-associated molecular patterns (DAMPs) and trigger an immune response in the host. CW-derived DAMPs might be a component of the complex system of surveillance of CW integrity (CWI), that plants have evolved to detect changes in CW properties. Microbial CWDEs can activate the plant CWI maintenance system and induce compensatory responses to reinforce CWs during infection. Recent evidence indicates that the CWI surveillance system interacts in a complex way with the innate immune system to fine-tune downstream responses and strike a balance between defense and growth.

scholarly journals Poaceae-specific cell wall-derived oligosaccharides activate plant immunity via OsCERK1 during Magnaporthe oryzae infection in rice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chao Yang ◽  
Rui Liu ◽  
Jinhuan Pang ◽  
Bin Ren ◽  
Huanbin Zhou ◽  
...  
Keyword(s):  
Cell Wall ◽  
Immune Responses ◽  
Magnaporthe Oryzae ◽  
Plant Cell Wall ◽  
Plant Immunity ◽  
Host Cells ◽  
Specific Cell ◽  
Chitin Binding Protein ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

AbstractMany phytopathogens secrete cell wall degradation enzymes (CWDEs) to damage host cells and facilitate colonization. As the major components of the plant cell wall, cellulose and hemicellulose are the targets of CWDEs. Damaged plant cells often release damage-associated molecular patterns (DAMPs) to trigger plant immune responses. Here, we establish that the fungal pathogen Magnaporthe oryzae secretes the endoglucanases MoCel12A and MoCel12B during infection of rice (Oryza sativa). These endoglucanases target hemicellulose of the rice cell wall and release two specific oligosaccharides, namely the trisaccharide 31-β-D-Cellobiosyl-glucose and the tetrasaccharide 31-β-D-Cellotriosyl-glucose. 31-β-D-Cellobiosyl-glucose and 31-β-D-Cellotriosyl-glucose bind the immune receptor OsCERK1 but not the chitin binding protein OsCEBiP. However, they induce the dimerization of OsCERK1 and OsCEBiP. In addition, these Poaceae cell wall-specific oligosaccharides trigger a burst of reactive oxygen species (ROS) that is largely compromised in oscerk1 and oscebip mutants. We conclude that 31-β-D-Cellobiosyl-glucose and 31-β-D-Cellotriosyl-glucose are specific DAMPs released from the hemicellulose of rice cell wall, which are perceived by an OsCERK1 and OsCEBiP immune complex during M. oryzae infection in rice.

scholarly journals Hypersensitive Responses in Plants

2019 ◽  
Author(s):  
Ankita Thakur ◽  
Shalini Verma ◽  
Vedukola P Reddy ◽  
Deepika Sharma
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Hypersensitive Response ◽  
Plant Cell Wall ◽  
Defense Mechanism ◽  
Avirulence Gene ◽  
Signal Molecules ◽  
Dead Cell ◽  
Natural Defense ◽  
Molecular Patterns

Hypersensitivity is a natural defense for plants in response to a variety of pathogens such as viruses, bacteria, fungi and is characterized by a programmed cell death (PCD) accompanied by an accumulation of toxic compounds within the dead cell. Hypersensitive response (HR) is considered a biochemical reaction rather than a structural defense mechanism but can be seen with the naked eye or with a microscope. There are two types of hypersensitive responses: structural and induced. PCD is seen in both structural as well as in induced hypersensitive response. PCD is extreme resistance shown by the plants in which it kills its cells (suicidal death), upon a perception of the pathogen to deprive it of nutritional supply and stops its growth. Cell death plays a central role in innate immune responses in both plants and animals. Apoptosis and autophagy are physiological processes and two forms of biochemical PCD. Induced hypersensitive response comes out when the plant recognizes specific pathogen-produced signal molecules known as elicitors. Recognition of elicitors by the host plants activates an army of biochemical reactions. These reactions include an oxidative burst of reactive oxygen species (ROS), alterations in plant cell wall also including cell wall immunity (CWI) and damage-associated molecular patterns (DAMPs), induction of phytoalexins and synthesis of PR proteins. These all, are comprised under the first line of defense of plants which come into action after recognition of conserved molecules characteristic of many microbes. These are called elicitors and are known as microbeassociated or pathogen-associated molecular patterns (MAMPs or PAMPs). The second line of defense of plants is the recognition of effectors through plant resistance gene products known as R genes, which result in effector-triggered immunity (ETI). This is supported by the gene for gene hypothesis. Avirulence gene encodes a protein which is specifically recognized by genotypes of the host plant harboring the matching resistance genes.

scholarly journals Extracellular Polysaccharides from Xanthomonas axonopodis pv. manihotis Interact with Cassava Cell Walls During Pathogenesis

1997 ◽  
Vol 10 (7) ◽  
pp. 803-811 ◽  
Author(s):  
B. Boher ◽  
M. Nicole ◽  
M. Potin ◽  
J. P. Geiger
Keyword(s):  
Cell Wall ◽  
Monoclonal Antibodies ◽  
Host Cell ◽  
Cell Walls ◽  
Plant Cell Wall ◽  
Infection Process ◽  
Extracellular Polysaccharides ◽  
Xanthomonas Axonopodis ◽  
Cassava Leaves ◽  
Host Cell Wall

The location of lipopolysaccharides produced by Xanthomonas axonopodis pv. manihotis during pathogenesis on cassava (Manihot esculenta) was determined by fluorescence and electron microscopy immunolabeling with monoclonal antibodies. During the early stages of infection, pathogen lipopolysaccharides were detected on the outer surface of the bacterial envelope and in areas of the plant middle lamellae in the vicinity of the pathogen. Later in the infection process, lipopolysaccharide-specific antibodies bound to areas where the plant cell wall was heavily degraded. Lipopolysaccharides were not detected in the fibrillar matrix filling intercellular spaces of infected cassava leaves. Monoclonal antibodies specific for the exopolysaccharide xanthan side chain labeled the bacteria, the fibrillar matrix, and portions of the host cell wall. The association of Xanthomonas lipopolysaccharides with host cell walls during plant infection is consistent with a role of these bacterial extracellular polysaccharides in the infection process.

scholarly journals The Role of Peptide Signals Hidden in the Structure of Functional Proteins in Plant Immune Responses

2019 ◽  
Vol 20 (18) ◽  
pp. 4343 ◽  
Author(s):  
Irina Lyapina ◽  
Anna Filippova ◽  
Igor Fesenko
Keyword(s):  
Immune Responses ◽  
Defense Responses ◽  
Innate Immune ◽  
Functional Protein ◽  
Diverse Range ◽  
Peptide Signals ◽  
Plant Pathogen Interactions ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Plants have evolved a sophisticated innate immune system to cope with a diverse range of phytopathogens and insect herbivores. Plasma-membrane-localized pattern recognition receptors (PRRs), such as receptor-like kinases (RLK), recognize special signals, pathogen- or damage-associated molecular patterns (PAMPs or DAMPs), and trigger immune responses. A growing body of evidence shows that many peptides hidden in both plant and pathogen functional protein sequences belong to the group of such immune signals. However, the origin, evolution, and release mechanisms of peptide sequences from functional and nonfunctional protein precursors, known as cryptic peptides, are largely unknown. Various special proteases, such as metacaspase or subtilisin-like proteases, are involved in the release of such peptides upon activation during defense responses. In this review, we discuss the roles of cryptic peptide sequences hidden in the structure of functional proteins in plant defense and plant-pathogen interactions.

scholarly journals The Role of Glycoside Hydrolases in Phytopathogenic Fungi and Oomycetes Virulence

2021 ◽  
Vol 22 (17) ◽  
pp. 9359
Author(s):  
Vahideh Rafiei ◽  
Heriberto Vélëz ◽  
Georgios Tzelepis
Keyword(s):  
Cell Wall ◽  
Plant Cell Wall ◽  
Hydrolytic Enzymes ◽  
Fungal Species ◽  
Phytopathogenic Fungi ◽  
Glycoside Hydrolases ◽  
Cell Wall Degrading Enzymes ◽  
Plant Host ◽  
Successful Infection ◽  
Molecular Patterns

Phytopathogenic fungi need to secrete different hydrolytic enzymes to break down complex polysaccharides in the plant cell wall in order to enter the host and develop the disease. Fungi produce various types of cell wall degrading enzymes (CWDEs) during infection. Most of the characterized CWDEs belong to glycoside hydrolases (GHs). These enzymes hydrolyze glycosidic bonds and have been identified in many fungal species sequenced to date. Many studies have shown that CWDEs belong to several GH families and play significant roles in the invasion and pathogenicity of fungi and oomycetes during infection on the plant host, but their mode of function in virulence is not yet fully understood. Moreover, some of the CWDEs that belong to different GH families act as pathogen-associated molecular patterns (PAMPs), which trigger plant immune responses. In this review, we summarize the most important GHs that have been described in eukaryotic phytopathogens and are involved in the establishment of a successful infection.

scholarly journals Rearrangement of the Cellulose-Enriched Cell Wall in Flax Phloem Fibers over the Course of the Gravitropic Reaction

2020 ◽  
Vol 21 (15) ◽  
pp. 5322
Author(s):  
Nadezda Ibragimova ◽  
Natalia Mokshina ◽  
Marina Ageeva ◽  
Oleg Gurjanov ◽  
Polina Mikshina
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Structural Changes ◽  
Plant Cell Wall ◽  
Complex Structure ◽  
Fiber Cell ◽  
Vertical Position ◽  
Cell Wall Polysaccharides ◽  
Cellulose Structure ◽  
Phloem Fibers

The plant cell wall is a complex structure consisting of a polysaccharide network. The rearrangements of the cell wall during the various physiological reactions of plants, however, are still not fully characterized. Profound changes in cell wall organization are detected by microscopy in the phloem fibers of flax (Linum usitatissimum) during the restoration of the vertical position of the inclined stems. To characterize the underlying biochemical and structural changes in the major cell wall polysaccharides, we compared the fiber cell walls of non-inclined and gravistimulated plants by focusing mainly on differences in non-cellulosic polysaccharides and the fine cellulose structure. Biochemical analysis revealed a slight increase in the content of pectins in the fiber cell walls of gravistimulated plants as well as an increase in accessibility for labeling non-cellulosic polysaccharides. The presence of galactosylated xyloglucan in the gelatinous cell wall layer of flax fibers was demonstrated, and its labeling was more pronounced in the gravistimulated plants. Using solid state NMR, an increase in the crystallinity of the cellulose in gravistimulated plants, along with a decrease in cellulose mobility, was demonstrated. Thus, gravistimulation may affect the rearrangement of the cell wall, which can enable restoration in a vertical position of the plant stem.

scholarly journals A Simple Technique For The Removal Of Plant Cell Protoplasm To Facilitate Scanning : Electron Microscopy Of Fungal Haustoria And Plant Cell Wall Features

2001 ◽  
Vol 9 (3) ◽  
pp. 14-15 ◽  
Author(s):  
B. A. Richardson ◽  
C. W. Mims
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Wall ◽  
Plant Cell ◽  
Host Plants ◽  
Plant Cell Wall ◽  
Simple Technique ◽  
Plant Cells ◽  
Host Cell Wall ◽  
Scanning Electron

Several years ago Honegger (1985) described a simple technique for removing plant cell protoplasm in order to reveal details of interfaces between plant cells and fungal structures. This technique involves the use of Ariel a commercially available washing powder (Proctor and Gamble) containing a Bacillus substilis derived protease. We since have used this technique with excellent results to examine not only the morphology of fungal haustoria inside leaf cells of various host plants but also features of the inner surface of the host cell wall with scanning electron microscopy (SEM). Here we describe the procedure we have used to prepare samples for study and provide examples of the types of images we have obtained from our samples.

scholarly journals Influence of cell wall polymers and their modifying enzymes during plant–aphid interactions

2019 ◽  
Vol 71 (13) ◽  
pp. 3854-3864 ◽  
Author(s):  
Christian Silva-Sanzana ◽  
José M Estevez ◽  
Francisca Blanco-Herrera
Keyword(s):  
Cell Wall ◽  
Defense Mechanisms ◽  
Plant Pathogens ◽  
Polymer Network ◽  
Aphid Infestation ◽  
Cell Wall Polymers ◽  
Colony Performance ◽  
Plant Pathosystems ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Abstract Aphids are a major issue for commercial crops. These pests drain phloem nutrients and transmit ~50% of the known insect-borne viral diseases. During aphid feeding, trophic structures called stylets advance toward the phloem intercellularly, disrupting cell wall polymers. It is thought that cell wall-modifying enzymes (CWMEs) present in aphid saliva facilitate stylet penetration through this intercellular polymer network. Additionally, different studies have demonstrated that host settling preference, feeding behavior, and colony performance of aphids are influenced by modulating the CWME expression levels in host plants. CWMEs have been described as critical defensive elements for plants, but also as a key virulence factor for plant pathogens. However, whether CWMEs are elements of the plant defense mechanisms or the aphid infestation process remains unclear. Therefore, in order to better consider the function of CWMEs and cell wall-derived damage-associated molecular patterns (DAMPs) during plant–aphid interactions, the present review integrates different hypotheses, perspectives, and experimental evidence in the field of plant–aphid interactions and discusses similarities to other well-characterized models such as the fungi–plant pathosystems from the host and the attacker perspectives.

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