Identification of genes associated with fruit ripening in Ziziphus jujuba using suppression subtractive hybridization approach

Abstract

Owing to the high nutritional value and extensive medicinal use of its products, Chinese jujube (Ziziphus jujuba Mill) is one of the most important fruit crops in China. However, jujube fruits are highly perishable and thus have a short shelf life, which is a serious hindrance to the industry. Better understanding of the molecular mechanisms underlying jujube fruit softening is fundamental to overcome the problem. Thus, both forward and reverse suppression subtractive hybridization (SSH) cDNA libraries were constructed to identify differentially expressed genes for fruit at half-red ripening stage and complete red stage. As a result of dot blot confirmation, a total of 154 differentially expressed genes were identified. After removed low-quality regions and screened for vector contamination, blasted with the non-redundant NCBI databases, 78.6 % of sequences exhibited high homology to previously identified or putative proteins. All the ESTs were annotated and classified according to the terms of the three main Gene Ontology vocabularies using the Blast2GO software. Furthermore, the quantitative real-time PCR was carried out for 17 genes to validate the genes differentially expressed from the SSH libraries. And the full-length sequences of galactose oxidase and aldehyde dehydrogenase genes were obtained. It is the first step to explore the functional genomics and regulatory networks during the storage period of jujube fruit. The identification of the genes differentially expressed is helpful to understand the ripening and softening of the jujube fruit at the molecular level.