海萝抗氧化酶系与失水响应因子表达模式分析

Expression patterns of antioxidant enzymes and desiccationresponsive factors in Gloiopeltis furcata(Gigartinales, Rhodophyta)

潮间带红藻海萝(Gloiopeltis furcata)对失水胁迫具有很强的耐受能力。为探索海萝周期性失水过程中的响应机制,本研究在24 h内设计了两次连续的失水-复水循环处理,测定了海萝抗氧化酶活力的变化情况。同时,利用转录组测序技术,结合荧光定量PCR方法(qRT-RCR),对海萝失水响应基因的转录表达进行了验证。结果表明:海萝转录组共组装到32681条基因。与对照组相比,处理组共表达了7161条差异表达基因(differentially expressed genes,DEGs)。KEGG分析显示,DEGs分布在代谢、环境信息加工、有机体系统、遗传信息加工、细胞进程等方面。海萝抗氧化酶活力测定发现,抗氧化能力对海萝响应失水胁迫十分重要。过氧化氢酶(CAT)、硫氧还蛋白还原酶(TrxR)、超氧化物歧化酶(SOD)参与抗氧化过程,其中CAT酶活力对海萝抵抗失水胁迫尤为重要。此外,qRT-PCR结果显示,海萝中渗透调节物质红藻糖苷合成的相关基因(GfUGPase、GfGK、GfGPDH)只对初次失水处理有正响应。而热激蛋白70基因(GfHSP70)、碳酸酐酶基因(GfCA)、MYB蛋白编码基因(GfMYB)以及谷胱甘肽S转移酶基因(GfGST)在两次失水过程中其转录水平均有上调表达,它们也参与了海萝失水响应机制。

The intertidal red seaweed Gloiopeltis furcata exhibits strong resistant ability to dehydration stress.To explore the responding mechanisms underlying periodic water loss processes in G.furcata,we designed two successive desiccation-dehydration cycles within 24 h and measured the changes in antioxidant enzyme activities in G.furcata.Transcriptome sequencing and quantitative reverse transcription–polymerase chain reaction(qRT-PCR)were used to verify the transcriptional expression patterns of dehydration-responsive genes.A total of 32,681 unigenes were assembled in transcripts.Compared with the control group,7,161 differentially expressed genes(DEGs)were expressed in the treatment groups.Kyoto Encyclopedia of Genes and Genomes analysis indicated that the DEGs were related to metabolism,environmental information processing,organismal system,genetic information processing,and cell processes.The results of antioxidant enzyme activity assay showed that antioxidant capacity was crucial for G.furcata response to dehydration stress.Catalase,thioredoxin reductase,and superoxide dismutase participate in antioxidant processes,and the activity of CAT is particularly important for the resistance to water loss.In addition,qRT-PCR results showed that genes involved only in floridoside synthesis(GfUGPase,GfGK,and GfGPDH)positively responded to the first desiccation treatment.Furthermore,the transcription levels of genes encoding heat shock protein 70(GfHSP70),carbonic anhydrase(GfCA),MYB-domain containing protein(GfMYB),and glutathione S-transferase(GfGST)were up-regulated during two dehydration periods,showing that these genes also participate in the mechanisms of desiccation response of G.furcata.