基于RNA-Seq技术的淹水胁迫下2个北美鹅掌楸无性系表达差异基因分析

Analysis of Differentially Expressed Genes in Two Clones of Liriodendron Tulipifera under Flooding Stress by RNA-Seq

北美鹅掌楸是优良用材和绿化树种,但不耐水涝的特征阻碍了其广泛推广应用。本研究对北美鹅掌楸耐淹无性系和淹水敏感无性系淹水胁迫4 d后的叶片进行Illumina HiSeqTM PE100高通量转录组测序,对2个无性系淹水前后的差异表达基因(DGEs)进行比较分析。结果表明,与对照相比,耐淹无性系检测到3809个差异基因中,2015个基因上调表达,1793个下调表达;敏感无性系淹水后检测到10389个差异基因,其中4488个基因上调表达,5901个基因下调表达。2个无性系淹水后的DGEs都富集到糖代谢、碳代谢、植物激素信号转导、光合作用、氨基酸代谢等方面,说明淹水胁迫对北美鹅掌楸的基础代谢影响较大。但耐淹无性系通过调节光反应中心的效率,淀粉、蔗糖、果糖等碳水化合物的储备,以及糖酵解等发酵途径来提供其生存所需能量,减轻淹水胁迫造成的不良影响,从而使耐淹北美鹅掌楸无性系表现出较高的淹水耐受性,为下一步北美鹅掌楸耐淹分子机理研究奠定了基础。

Liriodendron tulipifera is an excellent timber and greening tree species,but its extensive application is hindered by its waterlogging sensitive.In this study,Illumina HiSeqTM PE100 high-throughput transcriptome sequencing was performed on the leaves of flooding-sensitive and-tolerant clones of Liriodendron tulipifera for 4 d,and differential expression genes(DGEs)of the two clones before and after flooding were analyzed by gene ontology(GO)and genome database KEGG.Compared with the control,3809 differential genes detected by the flooded-tolerant clone,in which 2015 genes were up-regulated and 1793 genes were down-regulated.10389 differential genes were detected in sensitive clones after flooding,in which 4488 genes were up-regulated and 5901 genes were down-regulated.The functions of the differential genes of the two clones after flooding were jointly enriched in sugar metabolism,plant hormone signal transduction,photosynthesis,amino acid metabolism and other aspects,which indicated that flooding stress made great influence on the basic metabolism of Liriodendron tulipifera.However,the flooded-tolerant clones provide the energy required for the survival of plants under flooding by adjusting the photosynthetic efficiency of the two reaction centers of photosynthesis,increasing the accumulation of organic compounds(e.g.starch,sucrose metabolism,fructose,and so on),and promoting fermentation ways(such as glycolysis,ethanol fermentation,alanine fermentation),which could reduce the adverse effects of flooding stress,and enable the flooded-tolerant clone of Liriodendron Tulipifera to show higher tolerance.The results provide a basis for future research on the molecular mechanism of flooding tolerance in Liriodendron Tulipifera.