The Algal Polysaccharide Ulvan Induces Resistance in Wheat Against Zymoseptoria tritici Without Major Alteration of Leaf Metabolome

Abstract

This study aimed to examine the ability of ulvan, a water-soluble polysaccharide from the green seaweed Ulva fasciata, to provide protection and induce resistance in wheat against the hemibiotrophic fungus Zymoseptoria tritici. Matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) analysis indicated that ulvan is mainly composed of unsaturated monosaccharides (rhamnose, rhamnose-3-sulfate, and xylose) and numerous uronic acid residues. In the greenhouse, foliar application of ulvan at 10 mg.ml–1 2 days before fungal inoculation reduced disease severity and pycnidium density by 45 and 50%, respectively. Ulvan did not exhibit any direct antifungal activity toward Z. tritici, neither in vitro nor in planta. However, ulvan treatment significantly reduced substomatal colonization and pycnidium formation within the mesophyll of treated leaves. Molecular assays revealed that ulvan spraying elicits, but does not prime, the expression of genes involved in several wheat defense pathways, including pathogenesis-related proteins (β-1,3-endoglucanase and chitinase), reactive oxygen species metabolism (oxalate oxidase), and the octadecanoid pathway (lipoxygenase and allene oxide synthase), while no upregulation was recorded for gene markers of the phenylpropanoid pathway (phenylalanine ammonia-lyase and chalcone synthase). Interestingly, the quantification of 83 metabolites from major chemical families using ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) in both non-infectious and infectious conditions showed no substantial changes in wheat metabolome upon ulvan treatment, suggesting a low metabolic cost associated with ulvan-induced resistance. Our findings provide evidence that ulvan confers protection and triggers defense mechanisms in wheat against Z. tritici without major modification of the plant physiology.

Extracts of Saccharina latissima and Ulva lactuca affect the balance between growth and immunity in Arabidopsis thaliana

“…This conclusion contradicts the widely reported beneficial effects of Ulva extracts on plant growth and health (e.g. Kidgell et al 2019) and two specific studies reporting disease reductions and unaltered metabolomes after application of Ulva extracts to Triticum aestivum (de Borba et al 2021) and Medicago truncatula (Cluzet et al 2004). However, the inconsistent nature of our results in relation to disease protection are not unique (Abouraicha et al 2015;de Borba et al 2019;Delgado et al 2013).…”

Effect of enzyme-response Mag@CMCS@CPSG film on rice sheath blight disease (caused by Rhizoctonia solani) control and rice quality

“…Currently, it has been reported that it has antimicrobial activity against a variety of pathogenic microorganisms, and some researchers have found that magnolol achieves an antimicrobial effect by destroying plasma membranes (Sun et al, 2015a;Chen et al, 2019). In addition, the film-forming substances are polysaccharide compounds, which can induce plant disease resistance and may have a synergistic effect with magnolol (Borba et al, 2021;Dong et al, 2023). Field experiments proved that the Mag@CMCS@CPSG film had a good controlling effect on rice sheath blight disease.…”

Join the green team: Inducers of plant immunity in the plant disease sustainable control toolbox

“…Oryzae , Xanthomonas oryzae pv. Oryzicola Spray, Add to the bacterial solution Disrupt cell membranes, induce PAL, POX and PPO activity, callose deposition, increase synthesis of polyphenols and abscisic acid content Cellodextrins [45] Plant Grapevine Gray mold Botrytis cinerea Add elicitor to cell culture Induce defense-related genes, induction of oxidative burst and cytosolic calcium variation, phytoalexin accumulation Algino-oligosaccharides [46] , [47] Seaweed Soybean, Rice Rice blast Pseudomonas aeruginosa , Magnaporthe grisea Spray Induce PAL, POD, CAT activity, accumulation of phytoalexin Sulfated fucan oligosaccharides [48] Seaweed Tobacco Tobacco mosaic disease Tobacco mosaic virus Add elicitor to cell culture Induce PAL activity, PR genes, accumulation of phytoalexin and SA, release of H 2 O 2 Ulvans [49] , [50] Macroalgae Medicago truncatula, Common bean, Grapevine, Cucumber, Wheat Bean rust, Angular leaf spot, Septoria tritici blotch Colletotrichum trifolii , Erysiphe polygoni , Erysiphe necator , Sphareotheca fuliginea , Uromyces appendiculatus , Pseudocercospora griseola , Zymoseptoria tritici Spray Induce defense-related genes, ROS metabolism and octadecanoids Carrageenans [51] Rodophyta Tobacco Tobacco mosaic disease Tobacco mosaic virus, Botrytis cinerea, Pectobacterium carotovorum Spray Induce OXO, PAL activity, jasmonic acid related genes and the accumulation of several phenylpropanoid compounds

Fig. 5 Chemical structures of oligosaccharides with immune inducer activities.

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