【摘要】 肌醇半乳糖苷合成酶（galactinol synthase, GolS）是棉子糖家族寡糖（raffinose family oligosaccharides, RFOs）合成的关键酶,参与植物非生物胁迫响应。本研究以野生型（WT）和异源表达甘蓝型油菜（Brassica napus） GolS2基因（BnGolS2-OE）的拟南芥（Arabidopsis thaliana）为材料,探讨过表达BnGolS2转基因植株对盐胁迫的响应情况。结果表明:BnGolS2-OE对盐胁迫更敏感; NaCl条件下,其萌发势、萌发率、根长及生物量均显著低于WT。盐胁迫下, BnGolS2-OE的相对电导率显著高于WT,表明细胞膜受损加剧;同时,其超氧阴离子（O₂^-·）和过氧化氢（H₂O₂）含量较WT显著升高,提示氧化胁迫更为严重。进一步研究发现,盐胁迫诱导后, BnGolS2-OE中过氧化氢酶（CAT）、过氧化物酶（POD）和超氧化物歧化酶（SOD）活性虽有所升高,但增幅低于WT;且抗氧化相关基因SOD1和CAT1的表达量与WT更低。由此推测,甘蓝型油菜BnGolS2基因可能通过转录后调控抑制H₂O₂清除能力,从而负向调节拟南芥耐盐性。更多还原

【Abstract】 Galactinol synthase（GolS） is a key enzyme in the synthesis pathway of raffinose family oligosaccharides（RFOs）, which responds to various abiotic stresses. In this study, Arabidopsis thaliana with wildtype（WT） and heterologous expression of the GolS2 gene（BnGolS2-OE） from Brassica napus was used as materials to explore the response of transgenic plants overexpressing BnGolS2 to salt stress. The results showed that BnGolS2-OE was more sensitive to salt stress. Under the condition of NaCl, its germination potential, germination rate, root length and biomass were all significantly lower than those of the WT. Under salt stress, the relative electrical conductivity of BnGolS2-OE was significantly higher than that of the WT, which indicated that the cell membrane of BnGolS2-OE was severely damaged, resulting in the outward flux of ions. Meanwhile, the content of superoxide anion（O₂^-·） and hydrogen peroxide（H₂O₂） in BnGolS2-OE was significantly higher than that in WT, suggesting that the oxidative stress,wasit more severe. Further studies revealed that after salt stress induction, the activities of catalase（CAT）, peroxidase（POD）, and superoxide dismutase（SOD） in BnGolS2-OE increased, but the increase were all lower than that in WT, and the expression levels of the antioxidant-related genes, SOD1 and CAT1, were lower than those in WT. It is hypothesized that the BnGolS2 gene of B. napus may negatively regulate salt tolerance in A. thaliana by inhibiting the H₂O₂ scavenging ability at post-transcriptional level.更多还原