Optimization of Exopolysaccharides Production by Porphyridium sordidum and Their Potential to Induce Defense Responses in Arabidopsis thaliana against Fusarium oxysporum

Abstract

Polysaccharides from marine algae are one novel source of plant defense elicitors for alternative and eco-friendly plant protection against phytopathogens. The effect of exopolysaccharides (EPS) produced by Porphyridium sordidum on elicitation of Arabidopsis thaliana defense responses against Fusarium oxysporum was evaluated. Firstly, in order to enhance EPS production, a Box–Behnken experimental design was carried out to optimize NaCl, NaNO3 and MgSO4 concentrations in the culture medium of microalgae. A maximum EPS production (2.45 g/L) higher than that of the control (0.7 g/L) was observed for 41.62 g/L NaCl, 0.63 g/L NaNO3 and 7.2 g/L MgSO4 concentrations. Structurally, the EPS contained mainly galactose, xylose and glucose. Secondly, the elicitor effect of EPS was evaluated by investigating the plant defense-related signaling pathways that include activation of Salicylic or Jasmonic Acid-dependent pathway genes. A solution of 2 mg/mL of EPS has led to the control of fungal growth by the plant. Results showed that EPS foliar application induced phenylalaline ammonia lyase and H2O2 accumulation. Expression profile analysis of the defense-related genes using qRT-PCR revealed the up-regulation of Superoxide dismutases (SOD), Peroxidase (POD), Pathogenesis-related protein 1 (PR-1) and Cytochrome P450 monooxyge-nase (CYP), while Catalase (CAT) and Plant defensin 1.2 (PDF1.2) were not induced. Results suggest that EPS may induce the elicitation of A. thaliana’s defense response against F. oxysporum, activating the Salicylic Acid pathway.

Purification, structural characterization and immunological activity of Sibiraea laexigata (L.) Maxim polysaccharide

“…Besides, the sulfate content in SLMPs-1-1 was significantly higher than that in SLMPs-2-1, and the two fractions were both acidic polysaccharides because they contained higher uronic acid content (22.4 and 20.3%, respectively). Many studies have shown that the polysaccharide can show good bioactive functions when sulfate content is higher, so SLMPs-1-1 will be preferred for further animal experiments ( 31 ).…”

Exopolysaccharides from Marine Microbes: Source, Structure and Application

“…It can be effective not only in animal bacteria, but also in plant bacteria. Marwa Drira et al found that EPS produced by Porphyridium sordidum had led to the control of fungal growth by the plant, and EPS could act as an inducer to enhance the resistance of A. thaliana to F. oxysporum [ 24 ]. In addition, the sulfated EPS from Porphyridium sp.…”

“…The complex and diverse structure of EPS endows them with unique biological activities and functions [ 13 , 14 , 15 , 16 ]. Now, EPS, as a major active component of marine microbial resources [ 5 , 17 ], have become a new research hotspot, with advances in modern separation and analysis techniques [ 12 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. First, because the EPS are produced by marine microorganisms, this is an important factor for them to survive in these extreme environments, such as high pressure, high temperatures, and high salinity [ 25 ].…”

Medicinal plant‐associated rhizobacteria enhance the production of pharmaceutically important bioactive compounds under abiotic stress conditions

“…Exo polysaccharide-producing bacteria aid in the separation of free and insoluble phosphorus in soils, as well as the circulation of critical nutrients to the crop for appropriate growth and development and protection from external infections [142]. Because of the secretion of active indicator molecules during beneficial contacts, EPS is extremely effective and produces a defence reaction during the infection process [143]. EPS also bound positive ion, including Na+, implying a role in salt stress mitigation by lowering the amount of Na+ existing for plant use [144].…”