乌头子根膨大过程的转录组分析

Transcriptome Analysis of the Expanded Daughter Root of Aconitum carmichaelii

对乌头子根进行转录组测序,探讨调控乌头子根膨大的分子机制。选取乌头膨大过程的3个时间点即S1(1 d)、S2(31 d)、S3(61 d)进行转录组测序,筛选调控乌头子根膨大过程的相关差异表达基因,使用实时荧光定量聚合酶链式反应(qRTPCR)进行验证。转录组测序组装获得73600条单基因(Unigenes);通过比较转录组分析,得到差异表达基因(DEGs)一共7555条。S2/S1(S2相对于S1)、S3/S2(S3相对于S2)、S3/S1(S3相对于S1)比较组中分别得到2560、2171、6320条DEGs。KEGG富集分析显示差异表达基因主要参与了淀粉和蔗糖代谢、植物激素信号转导、植物-病原体作用和苯丙烷生物合成等代谢途径;其中淀粉生物合成途径上调而木质素生物合成下调是膨大过程的主要事件。植物激素信号转导中生长素、脱落酸、细胞分裂素和赤霉素这些途径相关基因参与调控乌头子根膨大过程。筛选这些膨大相关途径的差异表达基因进行qRT-PCR,结果与转录组数据表达模式具有一致性。本研究首次探讨乌头子根膨大过程的动态转录变化,挖掘参与调控乌头子根膨大过程的相关候选基因,为进一步研究乌头子根发育调控分子机制提供线索。

Transcriptome sequencing was performed on the daughter root of Aconitum carmichaelii(DR)to explore the underlying molecular mechanism regulating the root expansion.DR at three time points during the expansion stages,namely S1(1 d),S2(31 d)and S3(61 d),were harvested for sequencing.The identified differentially expressed genes(DEGs)were validated by real-time quantitative polymerase chain reaction(qRT-PCR).73600 unigenes were obtained via de novo assembly,including 7555 DEGs that are differentially expressed by comparative transcriptome analysis.There were 2560,2171 and 6320 DEGs in the three pair-wise comparison groups of S2/S1(S2 with respect to S1),S3/S2(S3 with respect to S2),S3/S1(S3 with respect to S1),respectively.KEGG enrichment analysis showed that DEGs were mainly involved in starch and sucrose metabolism,plant hormone signal transduction,plant-pathogen interaction and phenylpropane biosynthesis.The genes in starch biosynthesis pathway were up-regulated and these genes in lignin biosynthesis were down-regulated,which was considered as a sign in the root expansion.The genes related to auxin,abscisic acid,cytokinin and gibberellin were involved in regulating the process of enlargement.Through testing a subset of candidate genes in these pathways using qRT-PCR,a pattern similar to that revealed by transcriptome sequencing was revealed.This study is the first to explore the dynamic transcriptional changes in the process of DR enlargement,and excavate the related genes involved in the regulation of the enlargement process,which provides clues for further research on the molecular mechanism of DR.