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

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.

Author(s):  
Thea Magrone ◽  
Manrico Magrone ◽  
Matteo Antonio Russo ◽  
Emilio Jirillo

Background: Despite the evidence that plants do not possess sessile cells, they are able to mount a vigorous immune response against invaders or under stressful conditions. Mechanisms of action: Plants are endowed with pattern recognition receptors (PPRs) which perceive damage-associated molecular patterns and microbe-associated molecular patterns or pathogen-associated molecular patterns (PAMPs), respectively. PPR activation leads to either the initiation of PAMP-triggered immunity (PTI) (early response) or the effectortriggered immunity (ETI). Both PTI and ETI contribute to plant systemic acquired resistance as also an expression of immunological memory or trained immunity. Plant immune receptors: PTI is initiated by activation of both receptor-like kinases and receptor-like proteins, while ETI depends on nucleotide-binding leucine-rich-repeat protein receptors for microbe recognition. Peptides involved in plant defenses: Plant chloroplasts contribute to both PTI and ETI through production of peptides which act as hormones or phytocytokines. Salicylic acid, jasmonic acid and ethylene are the major compounds involved in plant defense. Specific aims: The interaction between plant receptors and/or their products and bacterial components will be discussed. Also emphasis will be placed on plant microbiome for its contribution to plant immune response. Finally, the mutual interplay between insects and plants will also be illustrated. Conclusion: A better knowledge on plant immunity may pave the way for the exploitation of plant derivatives in the field of agriculture and medicine, as well.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 399
Author(s):  
Riccardo Lorrai ◽  
Simone Ferrari

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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chao Yang ◽  
Rui Liu ◽  
Jinhuan Pang ◽  
Bin Ren ◽  
Huanbin Zhou ◽  
...  

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.


2019 ◽  
pp. 89-94
Author(s):  
Pedro Filho Noronha Souza

Plant defense mechanisms are divided into two phases; (1) the Pathogen-Triggered Immunity (PTI), which is basal resistance and; (2) Effector-Triggered Immunity (ETI) or induced resistance, the second line of defense of plants [1,2]. The PTI response is rapidly active by plants after recognizing pathogens effectors, which could be MAMPS or PAMPs (Microbe/pathogen-associated molecular patterns, e.g., bacterial flagellin), DAMPs (Damage-associated molecular patterns, e.g., fungal haustorium), and VAMPs (Viral-associated molecular patterns, e.g., double-stranded RNA of viruses). The recognition of pathogens effectors is performed by Pattern Recognition Receptors (PRR) [3-6].


2021 ◽  
Vol 31 (3) ◽  
pp. 517-527
Author(s):  
Serban BALANESCU ◽  
◽  
Elena BARBU ◽  
Camelia GEORGESCU ◽  
Andreea Catarina POPESCU ◽  
...  

Inflammation is involved in initiation, development and complications of the vast majority of non-communicable diseases. Recent research demonstrated that infl ammation is involved in pathogenesis of all major cardiovascular diseases. Different endogenous factors (LDL, nucleic acid strands, uric acid – collectively called „Damage Associated Molecular Patterns – DAMPs”) activate dedicated receptors („Pattern Recognition Receptors – PRR”) on monocytes, macrophages or dendritic cells responsible for the innate immunologic response. They have a major role in natural defense mechanisms against different pathogens and in normal conditions have a protective role. Among PRRs „NOD-like, leucin rich, pyrin containing (NLRP)” receptors are a 14-member family located in the cytoplasm. One of these is the NLRP3 resulting from nuclear transcription under the infl uence of NF-kB, a second messenger from membrane PRRs to the nucleus. Mostly the same factors responsible for NLRP3 intracellular expression stimulate its oligomerization resulting in a large protein complex, the NLRP3 infl ammasome. This activates caspase-1 responsible for IL-1b and IL-18 production and initiates an inflammatory reaction leading to various pathologic processes, such as atherosclerosis, hypertension, diabetes and heart failure. This is the current story as we know it of the NLRP3 infl ammasome, a small intracellular component that when inappropriately activated may does more harm than good.


Author(s):  
Athanasia pavlopoulou ◽  
Ezgi Karaca ◽  
Alma Balestrazzi ◽  
Alexandros Georgakilas

In plants and animals, endogenous biological molecules, termed damage-associated molecular patterns (DAMPs) or alarmins, are released by damaged, stressed or dying cells following abiotic stress such as radiation and drought stress. In turn, a cascade of downstream signaling events is initiated leading to the up-regulation of defense-related genes. In the present study, in an effort to investigate the conservation status of the molecular mechanisms implicated in the danger signaling, thorough in silico phylogenetic and structural analyses of the effector biomolecules were performed in taxonomically diverse plant species. On the basis of our results, the defense mechanisms appear to be largely conserved within the plant kingdom. Of note is our finding that the sequence and/or function of several components of these mechanisms were found to be conserved in animals, as well.


APOPTOSIS ◽  
2021 ◽  
Vol 26 (3-4) ◽  
pp. 152-162
Author(s):  
Atsushi Murao ◽  
Monowar Aziz ◽  
Haichao Wang ◽  
Max Brenner ◽  
Ping Wang

AbstractDamage-associated molecular patterns (DAMPs) are endogenous molecules which foment inflammation and are associated with disorders in sepsis and cancer. Thus, therapeutically targeting DAMPs has potential to provide novel and effective treatments. When establishing anti-DAMP strategies, it is important not only to focus on the DAMPs as inflammatory mediators but also to take into account the underlying mechanisms of their release from cells and tissues. DAMPs can be released passively by membrane rupture due to necrosis/necroptosis, although the mechanisms of release appear to differ between the DAMPs. Other types of cell death, such as apoptosis, pyroptosis, ferroptosis and NETosis, can also contribute to DAMP release. In addition, some DAMPs can be exported actively from live cells by exocytosis of secretory lysosomes or exosomes, ectosomes, and activation of cell membrane channel pores. Here we review the shared and DAMP-specific mechanisms reported in the literature for high mobility group box 1, ATP, extracellular cold-inducible RNA-binding protein, histones, heat shock proteins, extracellular RNAs and cell-free DNA.


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