秋茄(Kandelia candel L.)响应重金属胁迫的数字基因表达谱

Digital Gene Expression Profiling Analysis of Kandelia candel L. in Response to Artificial Heavy Metal Stress

基于高通量测序的数字基因表达谱(DGE)技术,对重金属污水胁迫处理组和对照组秋茄材料进行转录组测序分析。结果表明,重金属污水胁迫处理样品与对照样品相比,共筛选出的3 097个差异表达基因,其中2 202个表达上调,895个表达下调。GO功能显著性富集分析出38个GO分类条目,大量与生长发育,代谢调控,环境刺激响应相关的基因表现为富集。进一步的KEGG代谢途径分析表明,差异表达基因主要与糖类、核酸、蛋白质和脂质等生物大分子代谢、能量代谢以及次生代谢过程有关。转录因子分析发现b HLH,MYB,NAC和WRKY在重金属胁迫中发挥重要作用。此外,重金属胁迫还促进萜类、黄酮类化合物生物合成的关键酶基因(牻牛儿基焦磷酸合酶(Unigene0029352)、黄酮醇合成酶(Unigene0010384))的表达,进而促进秋茄有效成分的积累;显著诱导细胞分裂素相关基因type-b响应调节子ARR2(Unigene0033740)的表达、抑制油菜素内酯的信号转导组分基因BSK(Unigene0008986)的表达,进而提高秋茄对重金属胁迫的适应能力。实验选取了5个与环境刺激响应密切相关的基因,通过qRT-PCR验证了它们在重金属污水胁迫处理下的表达差异,结果与数字基因表达谱分析的结果较为一致,证实了差异表达基因数据的有效性。说明在重金属胁迫处理下,秋茄通过调节基因表达提高自身对污染胁迫的耐受能力。

Digital Gene Expression Profiling （ DGE）technique was used to analyze the differences in gene expressions of Kandelia candel under artificial heavy metal treatment. A total of 3097 differential expressed genes （ DEGs）were screened. Compared with the control treatment samples,2202 DEGs were upregulated and 895 DEGs were downregulated in the heavymetal water treatment samples. By gene ontology （ GO） ,38 DEGs were enriched in the processes of growth,metabolismregulation and environmental stimuli response. KEGG pathway enrichment analysis showed that these DEGs were involvedin various pathways of biological macromolecules metabolism,energy metabolism and secondary metabolism,such as sugar,protein,nucleic acid and lipid biosynthesis pathways. By transcription factor analysis,bHLH,MYB,NAC and WRKYplayed vital role in response to heavy metal stress. The geranyl pyrophosphate synthase （ Unigene0029352）and flavonolsynthase （ Unigene0010384）involved in terpenoid and flavonoid biosynthesis were up-regulated by heavy metal stressmight be the reason for the enhancement for the active ingredients accumulation in K. candel. The significantly promotion ofthe typeb response regulator ARR2 （ Unigene0033740）involved in the signal transduction of cytokinins by heavy metalstress,and the inhibition of serine / threonineprotein kinase BSK （ Unigene0008986）involved in the signal transduction ofbrassinolide by heavy metal stress might enhance the stress tolerance in K. candel. Five randomly selected ‘ responses tostimulus’related genes were used to confirm the accuracy of DGE.