条斑紫菜半胱氨酸合成酶基因表达对重金属铅胁迫的响应

Response of Cysteine Synthase Gene Expression to Lead Stress in Porphyra yezoensis Ueda

为了研究条斑紫菜的重金属解毒机制,分别采用Pb2＋1、4、7、10 mg/L对条斑紫菜叶状体进行短期铅胁迫,同时,用10 mg/L的Pb2＋对叶状体进行持续铅胁迫,胁迫处理后提取总RNA并采用实时荧光定量PCR技术检测条斑紫菜半胱氨酸合成酶基因（PyCSase-B）的表达变化。结果显示,铅胁迫能迅速且显著诱导PyCSase-B的表达。短期铅胁迫试验中,随着Pb2＋质量浓度的升高,PyCSase-B的表达量呈先上升而后下降的趋势,在7 mg/L Pb2＋胁迫下,PyCSase-B的表达量最高,是未处理样品的2.73倍。持续铅胁迫试验中,在前6 h内随着处理时间的增加,PyCSase-B的表达逐步上升,在6 h时PyCSase-B的表达量最高,是未处理样品的3.71倍;在8~12 h内PyCSase-B的表达量一直在较高水平波动。铅胁迫诱导PyCSase-B表达,说明PyCSase-B参与了条斑紫菜叶状体的重金属解毒过程。

To investigate the mechanism of heavy metal detoxification in intertidal red alga Porphyra yezoensis Udea,the expression of cysteine synthase gene（PyCSase-B） in P.yezoensis thalli responding to lead stress was examined.Thalli were subjected to seawater treatment with different concentration of lead（1,4,7,10 mg/L Pb2＋）for 2 h,and then subjected to seawater treatment with 10 mg/L Pb2＋ for 12 h.Then total RNA was extracted from thalli,and the relative mRNA levels of PyCSase-B were examined using real-time fluorescence quantitative PCR.The result showed lead stress could rapidly and significantly induce the expression of PyCSase-B in P.yezoensis thalli.In the treatment of short-term lead stress,the expression of PyCSase-B was induced under 1 mg/L Pb2＋ stress,reached its peak under 7 mg/L Pb2＋ stress,and then fall.The relative mRNA level of PyCSase-B under 7 mg/L Pb2＋ stress was 2.73-fold higher than untreated sample.In the treatment of continuous lead stress,during the first 6 h the expression of PyCSase-B increased gradually,and reached its peak at 6 h.The relative mRNA level of PyCSase-B at 6 h was 3.71-fold higher than untreated sample.From 8 h to 12 h,the expression of PyCSase-B fluctuated at a high level.