Elicitor and resistance-inducing activities of  -1,4 cellodextrins in grapevine, comparison with  -1,3 glucans and  -1,4 oligogalacturonides

Abstract

Cellodextrins (CD), water-soluble derivatives of cellulose composed of beta-1,4 glucoside residues, have been shown to induce a variety of defence responses in grapevine (Vitis vinifera L.) cells. The larger oligomers of CD rapidly induced transient generation of H2O2 and elevation in free cytosolic calcium, followed by a differential expression of genes encoding key enzymes of the phenylpropanoid pathway and pathogenesis-related (PR) proteins as well as stimulation of chitinase and beta-1,3 glucanase activities. Most of these defence reactions were also induced by linear beta-1,3 glucans (betaGlu) and alpha-1,4 oligogalacturonides (OGA) of different degree of polymerization (DP), but the intensity of some reactions induced by CD was different when compared with betaGlu and OGA effects. Moreover, desensitization assays using H2O2 production showed that cells treated with CD remained fully responsive to a second application of OGA, suggesting a different mode of perception of these oligosaccharides by grape cells. None of CD, betaGlu, or OGA induced HSR gene expression nor did they induce cell death. In accordance with elicitor activity in grapevine cells, CD-incubated leaves challenged with Botrytis cinerea also resulted in a significant reduction of the disease. Data suggest that CD could operate via other distinct reaction pathways than betaGlu and OGA. They also highlight the requirement of a specific DP for each oligosaccharide to induce the defence response.

Cell wall integrity

“…69 Cellodextrins are the end products of cellulose degradation in plant cell walls. Cellodextrins with a degree of polymerization ³ 7 induce defense responses in grapevine, 70 consistent with results indicating that cellulase from Tricoderma viride can release cellodextrins which induce plant defenses. 71 Depolymerization of xyloglucan has been proposed to play an important role during both cell wall expansion and pathogen invasion.…”

Plant Cell Wall Polymers: Function, Structure and Biological Activity of Their Derivatives

“…The induction of oxidative burst, transient elevation of cytosolic Ca 2+ , expression of defense-related genes, and stimulation of chitinase and -1,3-glucanase activities were triggered by CD in grapevine cells. Also, CD oligomers with a degree of polymerization 7 enhanced protection in detached leaves of grapevine against Botrytis cinerea, suggesting CD are important elicitors of defense reactions [76]. These results have opened the door to the study of many other biological processes where CD may be involved and to elucidate their action mechanisms in plants.…”

Irritable Walls: The Plant Extracellular Matrix and Signaling

“…Indirect physiological alterations induced in cell wall-defective mutants or after transgenic or pharmacological interference with cell wall biosynthesis or structure [, induction of; Y, suppression of; as, antisense suppression; ASR, abiotic stress resistance; AXS, UDP-apiose/UDP-xylose synthase; CalS, callose synthase; CD, cell death, both programmed and necrotic; CE, cellulose; CesA, cellulose synthase catalytic subunit; CH, carbohydrates; DCB, 2,6-dichlorobenzonitrile; DR, disease resistance and reduced pathogen susceptibility; ET, ethylene; EXT, extensin; GM, glucomannan; GMD, GDP-Dmannose 4,6-dehydratase; HSR, hypersensitive to sugar; JA, jasmonic acid; PE, pectin; PME, pectin methyl esterase; SA, salicylic acid. (Aziz et al, 2007) acting as potent elicitors of innate immunity. This class of elicitors has been termed host-associated molecular patterns (Galletti et al, 2009) or damage-associated molecular patterns (Zipfel, 2009), in analogy to pathogen-associated molecular patterns (PAMPs; for review, see Zipfel, 2009).…”