三年生白木香机械伤害转录组学研究

The mechanical wound transcriptome of three-year-old Aquilaria sinensis

国产沉香为瑞香科(Thymelaeaceae)植物白木香(Aquilaria sinensis(Lour.)Gilg)含有树脂的木材。白木香树体只有在受到伤害等胁迫,才在伤口周围的木材内产生倍半萜等沉香类物质,但是伤害如何诱导沉香倍半萜生物合成途径至今尚未揭示。为揭示伤害诱导白木香结香的分子机制,本研究应用RNA测序技术对机械伤害后的白木香木质部转录组进行测序,研究其基因表达谱,挖掘其功能基因。本研究共获得40 295条表达序列标签(express sequence tags,EST),平均长度305 bp。经序列合并拼接,获得22 095条单基因簇(unigene)。通过核苷酸和蛋白质序列等方面的同源性分析,表明其中61.6%(13 611条)与其他生物的已知基因具有不同程度的同源性。通过功能分类研究(GeneOntology)和代谢途径分析(KEGG)获得参与沉香倍半萜合成的序列26条(编码7个关键酶)。这些基因的发现为研究沉香倍半萜化合物的生物合成途径及伤害诱导沉香形成的分子机制提供了基础数据。

Chinese agarwood is formed in the aromatic resinous wood formed in Aquilaria sinensis（Lour.） Gilg（botanical family： Thymelaeaceae）.Only when suffering stress of wound,etc,can A.sinensis produce sesquiterpenes etc.compounds of agarwood around wounds.However,little is known about how wound induced the biosynthesis pathway of sesquiterpenes.To reveal the molecular mechanism of wound-induced agarwood formation,RNA sequencing（RNA-seq） technology was used to investigate the profile of gene expression in A.sinensis treated by mechanical wounding and elucidate its functional gene.A total of 40 295 ESTs with an average read length of 305 bp were generated and 22 095 unigenes were formed by initial gene splicing.61.6% of these unigenes（13 611） were annotated using BLAST searches against the SwissProt,KEGG,Nr and Nt databases.Twenty-six unigenes（encoding 7 enzymes） were found to be involved in sesquiterpene of agarwood biosynthesis by bioinformatic tools of GeneOntology and KEGG.Novel genes that are potentially involved in sesquiterpenes biosynthesis were identified in A.sinensis,providing data for further sesquiterpenes biosynthesis pathway by molecular methods and the EST data establish a foundation for future studies in the molecular mechanisms of wound-induce agarwood formation in A.sinensis.