Oligosaccharides: Defense Inducers, Their Recognition in Plants, Commercial Uses and Perspectives

Abstract

Plants have innate immune systems or defense mechanisms that respond to the attack of pathogenic microorganisms. Unlike mammals, they lack mobile defense cells, so defense processes depend on autonomous cellular events with a broad repertoire of recognition to detect pathogens, which compensates for the lack of an adaptive immune system. These defense mechanisms remain inactive or latent until they are activated after exposure or contact with inducing agents, or after the application of the inductor; they remain inactive only until they are affected by a pathogen or challenged by an elicitor from the same. Resistance induction represents a focus of interest, as it promotes the activation of plant defense mechanisms, reducing the use of chemical synthesis pesticides, an alternative that has even led to the generation of new commercial products with high efficiency, stability and lower environmental impact, which increase productivity by reducing not only losses but also increasing plant growth. Considering the above, the objective of this review is to address the issue of resistance induction with a focus on the potential of the use of oligosaccharides in agriculture, how they are recognized by plants, how they can be used for commercial products and perspectives.

Spatial Distribution and Characterization of the Small-Molecule Metabolites and In Situ Hydrolyzed Oligosaccharides in the Rhizome of Glycyrrhiza uralensis by Desorption Electrospray Ionization-Mass Spectrometry Imaging and High-Resolution Liquid Chromatography–Mass Spectrometry

“…Carbohydrates play a crucial role as indispensable sources of energy and carbon skeletons for organic compounds and storage constituents. The study of Guarnizo et al has demonstrated that some oligosaccharides can act as the elicitors and consequently activate the defense responses of the plants …”

“…These ions distributed in the cork may serve as the signaling molecules playing a role in the protection of the rhizome against the pathogens and provision of sufficient nutrients. 45 Additionally, based on the well-established HILIC/IM-QTOF-HDMS E and efficient data processing available in the UNIFI platform, we could separate and characterize up to 16 peaks of oligosaccharides (Figure 8A), with their identification information detailed in Table S5. Using peak o6 (t R : 18.72 min; DP7; m/z 1151.3731) as a case (Figure 8B ) from the C n − ions could assist to primarily characterize the 1 → 4 linkage as the basic linear backbone.…”

Secondary Metabolism Rearrangements in Linum usitatissimum L. after Biostimulation of Roots with COS Oligosaccharides from Fungal Cell Wall

“…Although the mechanism underlying this observation is still unknown, it is possible that the application of exogenous COS oligosaccharides influenced the concentration of plant defense compounds, such as flavonoids or phenolic acids in the above- and below-ground tissues [ 55 ]. COS oligosaccharides are known to induce the production of phenolic compounds and specific phytoalexins with antifungal activity [ 56 , 57 ]. Biosynthesis is known to occur not only in the feeding sites of treated seedlings, but also in systemic roots and aerial tissues.…”

Plant Biostimulant as an Environmentally Friendly Alternative to Modern Agriculture

“…As a result, fewer pesticides may be required. Furthermore, these oligosaccharides promote the synthesis of defense enzymes, hormones, and osmotic regulators in plants, all of which increase the plant’s resistance to adverse environments. , Brown algal oligosaccharides enhance immune resistance through a mechanism that is reflected in multiple ways . These oligosaccharides greatly lengthen and increase the number of roots under stressful conditions, which enhances the plant’s ability to absorb nutrients and maintain general health .…”