Induction of Natural Defenses in Tomato Seedlings by Using Alginate and Oligoalginates Derivatives Extracted from Moroccan Brown Algae

Abstract

Polysaccharides extracted from marine algae have attracted much attention due to their biotechnological applications, including therapeutics, cosmetics, and mainly in agriculture and horticulture as biostimulants, biofertilizers, and stimulators of the natural defenses of plants. This study aimed to evaluate the ability of alginate isolated from Bifurcaria bifurcata from the Moroccan coast and oligoalginates derivatives to stimulate the natural defenses of tomato seedlings. Elicitation was carried out by the internodal injection of bioelicitor solutions. The elicitor capacities were evaluated by monitoring the activity of phenylalanine ammonia-lyase (PAL) as well as polyphenols content in the leaves located above the elicitation site for 5 days. Alginate and oligoalginates treatments triggered plant defense responses, which showed their capacity to significantly induce the PAL activity and phenolic compounds accumulation in the leaves of tomato seedlings. Elicitation by alginates and oligoalginates showed an intensive induction of PAL activity, increasing from 12 h of treatment and remaining at high levels throughout the period of treatment. The amount of polyphenols in the leaves was increased rapidly and strongly from 12 h of elicitation by both saccharide solutions, representing peaks value after 24 h of application. Oligoalginates exhibited an effective elicitor capacity in polyphenols accumulation compared to alginate polymers. The alginate and oligosaccharides derivatives revealed a similar elicitor capacity in PAL activity whereas the accumulation of phenolic compounds showed a differential effect. Polysaccharides extracted from the brown seaweed Bifurcaria bifurcate and oligosaccharides derivatives induced significantly the phenylpropanoid metabolism in tomato seedlings. These results contribute to the valorization of marine biomass as a potential bioresource for plant protection against phytopathogens in the context of eco-sustainable green technology.

Induction of Defense Gene Expression and the Resistance of Date Palm to Fusarium oxysporum f. sp. Albedinis in Response to Alginate Extracted from Bifurcaria bifurcata

“…Previous works have shown that the ulvan and glucuronan extracted from a green alga, Ulva lactuca, stimulate the natural defenses of tomato [31], olive tree [34] and post-harvest apple [35,36]. Likewise, alginate extracted from the brown algae B. bifurcata, could also stimulate the natural defenses of tomatoes [37] and date palm [29].…”

Plant stimulants and horticultural production

“…35 Currently, there is more attention for using seaweed extract in horticulture production as part of the crop management program, there are different Seaweeds extract used in different crops while, the use of extracts of brown algae are the major one in the horticultural sector. 36…”

Cloning, expression and improvement of catalytic activity of alginate lyase by site-directed mutation

“…Alginate lyase degrees alginate by β-elimination process to form active oligosaccharides [2]. Alginate oligosaccharides (AOS) are used for a variety of purposes in food, medicine, chemical industry, and agriculture, including cholesterol reduction, antitumor, anti-inflammatory and bacteriostatic, antioxidant, immunity regulation, plant growth promotion, and antiviral materials [3][4][5][6]. Thus, it can be proved that high-activity alginate lyase becomes urgently needed.…”