中文摘要：

以琼胶寡糖处理坛紫菜Porphyra haitanensis,激发其防御反应,坛紫菜在18℃生长和35℃热激时的病烂现象得到明显改善。寡糖激发的防御信号能够杀死附生在藻上的细菌,健康藻上约94.7%的附生菌群在加入100μg.mL-1琼胶寡糖1 h内被杀死,但过氧化氢酶可部分抑制这种作用。利用3种抗生素组合获得无菌坛紫菜体系,回染致病细菌后,约60.8%的回染细菌在寡糖激发后的3 h内被消灭。这种附生细菌的减少现象不是源于琼胶寡糖的直接抑菌作用,可能与琼胶寡糖引起坛紫菜H2O2的瞬时暴发有关。结果表明,琼胶寡糖能够作为坛紫菜的抗性激发子,通过诱导坛紫菜自身的防御反应来减少附生细菌的数量,从而保持藻体的健康生长。

英文摘要：

The rot disease of Porphyra haitanens＆ cultured under 18℃ and 35℃ were obviously lightened by pretreatment with oligoagars. The defense response elicited by oligoagars was strong enough to kill epiphytic bacteria associated with the algal. Up to 94.7% of the resident bacterial flora of healthy plants was eliminated within 60 min after treatment by 100μg.mL-1 oligoagars. Addition of catalase prior to oligoagars partially inhibited this elimination. Mixture of three kinds of antibiotics was used to treat P haitanensis to get the asepsis culture systems. Approximately 60.8% of reinfected pathogenic bacteria on axenic algal were eliminated within 3 h after elicitation by oligoagars. Antimicrobial test revealed that oligoagars showed no direct toxicity to associated bacteria or pathogen, but a rapid release of hydrogen peroxide was observed after adding of oligoagars in medium. From these results, we infer that oligoagars can be recognized as defense elicitors by P. haitanensis to protect algal efficiently from infections by eliminating the associated pathogenic bacteria.