基于转录组测序的滇山茶花叶呈色机理分析

Coloring Mechanism Analysis of Mosaic Leaves in Camellia reticulata Lindl. Based on Sequencing of Transcriptome

该研究采用Illumina Hi-Seq2500高通量测序技术,对滇山茶的花叶(绿叶区和金叶区)的cDNA进行了转录组测序,分析滇山茶的花叶呈色机理。测序结果得到了228 862条单基因序列,筛选得到了4 851条差异表达基因。2 291条差异表达基因在GO数据库中有功能注释,1 826条差异表达基因被注释到COG数据库,这些差异表达基因被分为23个主要功能类别,其中大部分基因与滇山茶的生长和代谢有关。1 363条差异表达基因注释到了KEGG数据库,进一步筛选出了差异表达基因注释序列最多的15条代谢通路,其中卟啉和叶绿素代谢途径中的GluRS、δ-ALAD、ALAS基因和类黄酮合成途径中ANS、LAR、CHS基因与滇山茶的花叶形成密切相关。研究表明,滇山茶的花叶呈色是由于叶色相关代谢通路中大量的基因表达量发生变化引起的,并不是由单基因突变所致,病毒诱导的多个代谢途径基因沉默可能是滇山茶花叶呈色的主要原因。该研究丰富了滇山茶的转录组信息,并为滇山茶的彩叶品种培育提供了一定的参考。

In the present study, the cDNA of C. reticutata （floral lea{ and green leaf） were sequenced based on Illumina Hi-Seq2500 to analyze the leaf color mechanism. In total, 228 862 unigenes were obtained and 4 851 differential expressed genes （DEGs） were selected. 2 291 DEGs were divided into 31 GO terms, 1 826 DEGs were divided into 23 COG major functional categories. Most of these genes are related to its growth and metabolism. 1 363 DEGs were annotated into KEGG database, 15 pathways of DEGs mos annotated were screened out, GluRS, O-ALAD, ALAS, in the pathway of porphyrin and chlorophyll metabolism ANS, LAR, CHS in the pathway of flavonoid biosynthesis, are the key genes in its floral leaf formation. The coloration of the leaves was caused by a large amount of gene expression changes related to leaf color metabolic pathways, not caused by single gene mutations, the silencing of homologous genes in- duced by C. reticulata mosaic virus in Yunnan is probably the main reason for the formation of C. reticulata leaf coloration. These results greatly enriched genetic information of C. reticulata, and provide some reference for the cultivation of the colorful leaf varieties.