Laboratoire de Biotechnologies des Plantes Appliquées à l'Amélioration des Cultures, Faculté des Sciences de Sfax, Université de Sfax, 3038 Sfax, Tunisia.
Laboratoire de Génie Enzymatique et Microbiologie, Equipe de Biotechnologie des Algues, Ecole Nationale d'Ingénieurs de Sfax, Université de Sfax, 3038 Sfax, Tunisia.
Biomolecules. 2021 Feb 14;11(2):282. doi: 10.3390/biom11020282.
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 on elicitation of defense responses against was evaluated. Firstly, in order to enhance EPS production, a Box-Behnken experimental design was carried out to optimize NaCl, NaNO and MgSO 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 NaNO and 7.2 g/L MgSO 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 HO 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 . 's defense response against , activating the Salicylic Acid pathway.
海洋藻类多糖是一种新型植物防御诱导剂来源，可替代和环保地防治植物病原体。评估了由产生的胞外多糖 (EPS) 对诱导植物防御反应的效果。首先，为了提高 EPS 的产量，采用 Box-Behnken 实验设计优化了微藻培养基中 NaCl、NaNO 和 MgSO 的浓度。在 41.62 g/L NaCl、0.63 g/L NaNO 和 7.2 g/L MgSO 浓度下，观察到 EPS 的最大产量（2.45 g/L）高于对照（0.7 g/L）。结构上，EPS 主要含有半乳糖、木糖和葡萄糖。其次，通过研究植物防御相关的信号通路，包括激活水杨酸或茉莉酸依赖途径基因，评估 EPS 的诱导作用。2 mg/mL EPS 溶液可控制植物真菌生长。结果表明，EPS 叶面喷施诱导苯丙氨酸氨裂解酶和 HO 积累。使用 qRT-PCR 进行防御相关基因的表达谱分析显示，超氧化物歧化酶 (SOD)、过氧化物酶 (POD)、病程相关蛋白 1 (PR-1) 和细胞色素 P450 单加氧酶 (CYP) 的表达上调，而过氧化氢酶 (CAT) 和植物防御素 1.2 (PDF1.2) 未被诱导。结果表明，EPS 可能通过激活水杨酸途径诱导对的防御反应。
