Biology subjects

Pontiggia, D.

Publications and source records attributed to Pontiggia, D..

5 recordsLinked to original sources

bioRxiv2025

Enhancing Plant Immune Training and Protection through Damage- and Microbe-Associated Molecular Patterns from Anaerobic Digestate

Olive oil production is a major global agricultural industry that generates significant waste, particularly olive pomace, which poses environmental and economic challenges. Anaerobic digestion has emerged as a promising solution for its valorization into biogas and reducing its environmental impact. However, the resulting digestate remains underutilized and its long-term environmental impact is uncertain. Traditional disposal methods are costly and inefficient, underscoring the need for more sustainable approaches. In this study, olive pomace digestate was biorefined and its components were upcycled into soil amendments and plant immunostimulants. Metagenomic analysis revealed a diverse microbial community in the liquid fraction, including Luteimonas, Pseudomonas, and Caldicoprobacter. We obtained a MIcrobial Protein Extract (MIPE) from this biomass, containing precursors of microbe- and damage-associated molecular patterns including Flagellin, Elongation Factor Tu, and the phytocytokine Golven. Treatment with MIPE triggered a rapid plant immune response, characterized by increased hydrogen peroxide production, phosphorylation of mitogen-activated protein kinases, and the upregulation of defense-related genes such as CYP81F2, FRK1, and WRKY53. MIPE-induced priming enhanced Arabidopsis and tomato resistance to Botrytis cinerea and Pseudomonas syringae. Our findings highlight digestate as a source of bioelicitors, offering a sustainable alternative to chemical pesticides while enhancing plant immunity, valorizing olive mill waste and promoting sustainable agriculture.

plant biology↗

bioRxiv2025

Aphid effector Mp10 balances immune suppression and defence activation through EDS1-dependent modulation of plant DAMP responses

O_LIDamage-associated molecular pattern (DAMP)-triggered immunity (DTI) serves as a crucial first line of defence against aphid attack, yet the mechanisms by which aphids suppress this response remain unclear. C_LIO_LIBy investigating the colonisation of Arabidopsis thaliana by the highly polyphagous peach-potato aphid (Myzus persicae), we identified cell wall-derived DAMPs, specifically oligogalacturonides (OGs), as key in inducing DTI against aphids. The OG-responsive immune components BAK1/BKK1, CPK5/CPK6, GRP3, and EDS1 collectively contribute to DTI limiting aphid colonisation. C_LIO_LIWe found that aphids limit OG production during feeding. Additionally, the salivary chemosensory protein (CSP) effector Mp10/CSP4, which is known to be delivered into the cytoplasm of plant cells early in aphid attack, inhibits OG-induced DTI. C_LIO_LIWhile Mp10 suppresses OG-induced DTI, it also interacts with EDS1-mediated defences, enhancing aphid fecundity in the absence of EDS1 but restoring OG responsiveness under attack, revealing its broader role in immune modulation and effector-driven host adaptation. C_LI

plant biology↗

bioRxiv2024

Berberine Bridge enzyme-like oxidases orchestrate homeostatic control and signaling of oligogalacturonides in defense and wounding

Plant immunity is triggered by endogenous elicitors known as damage-associated molecular patterns (DAMPs). Oligogalacturonides (OGs) are DAMPs released from the cell wall (CW) demethylated homogalacturonan during microbial colonization, mechanical or pest-provoked tissue damage, and physiological CW remodeling. Berberine Bridge Enzyme-like (BBE-l) proteins named OG oxidases (OGOXs) have been proposed to govern OGs homeostasis, which is necessary to avoid deleterious growth-affecting hyper-immunity and possible cell death. Using OGOX1 over-expressing lines and ogox1/2 double mutants, we show that these enzymes determine the levels of active OGs vs. inactive oxidized products (oxOGs). The ogox1/2-deficient plants have elevated levels of OGs, while plants overexpressing OGOX1 accumulate oxOGs. The balance between OGs and oxOGs affect disease resistance against Pseudomonas syringae pv tomato, Pectobacterium carotovorum, and Botrytis cinerea depending on the microbial capacity to respond to OGs and metabolize oxOGs. Gene expression upon plant infiltration with OGs reveals that OGOXs orchestrate OG signaling in defense as well as upon tissue damage, pointing to these enzymes as apoplastic players in immunity and tissue repair. TeaserOxidases control the homeostasis of oligogalacturonides in the cell wall and play a pivotal role in the plant immunity.

plant biology↗

bioRxiv2024

Olive mill wastewater as a source of by-products promoting plant defense against microbial pathogens

Olive oil is a core component of the Mediterranean diet known for its nutritional properties and health benefits. Olive industry is moving to novel extraction systems for higher oil yield and quality and for waste reduction, which is a relevant problem in the process due to its toxicity and high disposal costs. Multi-Phase Decanter (DMF) is a modern two-phase system performed without adding water during the process. Using DMF, a wet by-product indicated as pate and consisting of the fruit pulp and vegetation water (VW) is recovered. The pate has a high content of potentially bioactive molecules that may be exploited to promote plant resistance against microbial pathogens. In this work, to identify by/products of biological interest, the VW recovered from the pate by centrifugation was subjected to fractionation by tangential-flow membrane filtration (TFMF), combining microfiltration (MF) and ultrafiltration (UF). High-resolution NMR spectroscopy indicated the presence of bioactive molecules such as flavonoids, hydroxytyrosol and oleuropein with known antimicrobial activity. High-Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD) was performed to detect the presence of pectic oligosaccharides in the fractions, showing the enrichment, in the UF-concentrate fraction, of oligogalacturonides (OGs), well known for the ability to elicit defense responses and protect plants against pathogen infections. Arabidopsis thaliana plants treated with TFMF fractions displayed induction of defense responses and exhibited resistance against microbial pathogens without adverse effects on growth and fitness. This study shows that pate by-products can potentially be exploited in agriculture as sustainable plant phyto-protectant. Graphical abstract(image created with BioRender)

plant biology↗

bioRxiv2023

BERBERINE BRIDGE ENZYME-LIKE OXIDASES OF CELLODEXTRINS AND MIXED-LINKED β-GLUCANS CONTROL SEED COAT FORMATION

A member of the Arabidopsis Berberine Bridge Enzyme-like (BBE-l) protein family named CELLODEXTRIN OXIDASE 2 (CELLOX2) has been characterized in this paper and shown to display structural and enzymatic features similar to the previously characterized CELLOX1. These include the capability to oxidize the mixed-linked {beta}-1[->]3/{beta}-1[->]4-glucans (MLGs), recently described as cell wall-derived damage-associated molecular patterns (DAMPs) that activate plant immunity. The two paralogous genes show a different expression profile. Unlike CELLOX1, CELLOX2 is not expressed in seedlings or in adult plants and is not involved in immunity against Botrytis cinerea. Both genes are expressed in a concerted manner in the seed coat during development: whereas CELLOX2 transcripts are detected mainly during the heart stage, CELLOX1 transcripts are detected later, when the expression of CELLOX2 decreases. Analysis of seeds of cellox1 and cellox2 knock-out mutants show alterations in the structure of the coat and mucilage, but not in their monosaccharide composition. We propose that the cell wall structure of specific organs is not only the result of a coordinated synthesis/degradation of polysaccharides but also of their exposure to enzymatic oxidation. Our results also reinforce the view that the family of BBE-l proteins is at least in part devoted to the control of the activity of cell wall-derived oligosaccharides acting as DAMPs. SENTENCETwo Arabidopsis BBE-like oxidases of the cell wall DAMPs cellodextrins and mixed-linked {beta}-glucans inactivate their elicitor activity. Seed coat and mucilage are altered in null mutants of two enzymes.

plant biology↗