Ricerc@Sapienza

Oligogalacturonides (OGs) are fragments of pectin released from the plant cell wall during insect or pathogen attack. They can be perceived by the plant as damage signals, triggering local and systemic defence responses. Here, we analyse the dynamics of local and systemic responses to OG perception in tomato roots or shoots, exploring their impact across the plant and their relevance in pathogen resistance.

Innate immune receptors, well known mediators of response to non-self-molecules and inflammation, also act as mediators of immunity triggered by ‘damage-associated molecular patterns’ (DAMPs). Pathogen-associated molecular patterns (PAMPs) cause inflammation in mammals and a rapid immune response in plants, while DAMPs trigger more complex responses, including immunity, tissue maintenance and repair. DAMPs, their receptors and downstream transduction mechanisms are often conserved within a kingdom or, due to convergent evolution, are similar across the kingdoms of life.

Aphids are among the most destructive pests in agriculture, causing direct damage to crops by feeding on phloem, as well as indirect losses by transmitting more than half of all described plant viruses. During feeding aphids secrete effector proteins into their hosts to manipulate cellular processes and promote infestation. Aphids are largely controlled by pesticides that are environmentally damaging and are being withdrawn from the market.

In order to cause a disease, pathogens need to break the plant cell wall and to this purpose they secrete degrading enzymes towards various cell wall components. Several oligosaccharides released during pathogenesis, such as the Oligogalacturonides (OGs) and Cellodextrins (CDs) upon the breakdown of the homogalacturonan and cellulose respectively, act as Damage-Associated Molecular Patterns (DAMPs) and activate immunity.

The plant cell wall is the barrier that pathogens must overcome to cause a disease and to this purpose they secrete degrading enzymes of the various cell wall components. Due to the complexity of these components, several types of oligosaccharide fragments may be released during pathogenesis and some of these can act as Damage-Associated Molecular Pattern (DAMPs). Well-known DAMPs are the oligogalacturonides (OGs) released upon degradation of homogalacturonan and the products of the cellulose breakdown, i.e. the cellodextrins (CDs).

Natural killer (NK) cells are innate lymphoid cells that play a major role in the immune surveillance against tumors and their activity is regulated through signals derived by a number of NK cell inhibitory and activating receptors as well as cytokines and other soluble factors released in the tumor microenvironment. Extracellular vesicles (EVs) are membrane-enclosed particles secreted by all cell types, both in healthy and diseased conditions, and are important mediators of intercellular communication.

Natural killer (NK) cells are innate lymphoid cells that play a pivotal role in tumor surveillance. Exosomes are nanovesicles released into the extracellular environment via the endosomal vesicle pathway and represent an important mode of intercellular communication. The ability of anticancer chemotherapy to enhance the immunogenic potential of malignant cells mainly relies on the establishment of the immunogenic cell death (ICD) and the release of damage-associated molecular patterns (DAMPs).