Identification of Genes Related to Cell Wall Metabolism and Fruit Ripening in Ziziphus jujube Using RNA-seq and Expression Analysis

Abstract

The transcriptome of Chinese jujube (Ziziphus jujube Mill.) fruit was characterized to determine which genes were involved in cell wall metabolism and ripening. Based on RNA-seq of fruit pulp, 61.243 contigs (mean length 440 nt) were assembled and 31.725 genes were identified (mean length 842 nt), of which 25.257 were annotated using a non-redundant protein sequence database (Nr). Finally, 8.409 of these genes were classified using the Gene Ontology (GO) functional annotation database into three major categories: cell component, molecular function, and biology process. Comparison of young and mature fruit transcripts showed that 1.206 genes were upregulated while 1.256 genes were downregulated. The 19 candidate genes related to cell wall metabolism and fruit ripening were selected from the differentially expressed genes (DEGs) for further study; qRT-PCR analysis showed that gene expression levels were up- or downregulated significantly at the stages of young and ripe fruit when compared to plant leaves.