珍珠芦荟白化苗的转录组分析

Transcriptomics Analysis of Leaf Albino Mutants of Aristaloe aristata

本研究旨在探明珍珠芦荟苗白化突变分子机制,挖掘相关功能基因,为珍珠芦荟品种选育提供依据。利用Illumina HiSeq测序平台对珍珠芦荟正常叶色苗WT、白化苗突变株ls和qj进行转录组高通量测序,并对测序结果进行功能注释分析。结果表明:本研究共得到67.72 Gb的有效数据(clean data),共获得122665条Unigenes;与正常株WT相比,突变株ls叶片中共筛选出914个差异表达基因(DEGs),其中453个上调,461个下调;突变株qj叶片中共获得1851个DEGs,其中868个上调,983个下调。通过GO功能富集和KEGG代谢途径分析,发现在2个突变株中,色素积累、细胞壁组成或生物发生、细胞壁、细胞外周、水解O-糖基化合物水解酶活性、作用于糖基键的水解酶活性过程,以及在次生代谢生物合成途径中被富集的差异表达基因较多,而与光合作用相关途径的差异基因未获得显著富集。在与光合作用相关途径中发现,突变株ls中porA、cab13基因呈显著下调表达,突变株qj中porA、moda基因呈显著下调表达。实时荧光定量检测结果证实了这些基因的相对表达量的变化趋势与转录组数据一致。porA为2个突变株共同下调表达的基因,porA基因下调会导致原叶绿素酸酯合成叶绿素酸酯的酶促反应受到影响,进而影响2个突变株的叶绿素合成,因此推测该基因下调对珍珠芦荟白化苗形成起着重要的作用。本研究探索了珍珠芦荟苗白化变异的转录组信息,筛选到表达差异显著的关键基因,为深入探讨珍珠芦荟苗白化突变分子机制提供重要的理论基础。

The purpose of the study is to ascertain the molecular mechanism of the albino mutation of Aristaloe aristata,screen related functional genes,and provide basis for the breeding.The Illumina HiSeq sequencing platform was used to carry out transcriptome high-throughput sequencing for normal leaf color seedlings WT,albino mutant ls and qj.The sequencing results were annotated and analyzed.A total of 67.72 Gb clean data was obtained.A total of 122665 unigene annotation results were obtained from functional annotation.For the analysis of Unigenes expression,a total of 914 differentially expressed genes(DEGs)in ls were screened out,among them,453 genes were up-regulated and 461 down-regulated.There were 1851 differentially expressed genes(DEGs)screened in qj,of which up-and down-regulated genes were 868 and 983,respectively.According to a comparative analysis of GO functional enrichment and KEGG metabolic pathway,it was found that in the two mutant strains,there were many DEGs enriched in pigment accumulation,cell wall organization or biogenesis,cell wall,cell periphery,hydrolase activity of hydrolyzing o-glycosyl compounds,hydrolase activity acting on glycosyl bonds,and biosynthesis pathway of secondary metabolism,while the DEGs related to photosynthesis were not significantly enriched.In the pathway related to photosynthesis,the expression of porA and cab13 were significantly down-regulated in mutant ls,and porA and moda were significantly down-regulated in mutant qj.The results of real-time reverse transcriptase PCR(qRT-PCR)confirmed the consistency of the relative expression trend and the transcriptome data of these genes.The expression of the key gene,porA,which was down-regulated in both mutants,was assumed to be a key factor in the formation of albino seedlings of A.aristate since it was found to affect the enzymatic reaction of protochlorophyllin ester to chlorophyllin ester and thereby affecting the chlorophyll synthesis of the two mutants.Our study explored the transcriptome information of albinism mutation of A.aristate,screened the key genes with significant expression differences,and would provide an important theoretical basis for further exploring the molecular mechanism of albinism mutation of A.aristate.