Comparative transcriptome profiling reveals cold stress responsiveness in two contrasting Chinese jujube cultivars

Abstract

Background: Low temperature is a major factor influencing the growth and development of Chinese jujube (Ziziphus jujuba Mill.) in cold winter and spring. Little is known about the molecular mechanisms enabling jujube to cope with different freezing stress conditions. To elucidate the freezing-related molecular mechanism, we conducted comparative transcriptome analysis between ‘Dongzao’ (low freezing tolerance cultivar) and ‘Jinsixiaozao’ (high freezing tolerance cultivar) using RNA-Seq. Results: More than 20,000 genes were detected at chilling (4°C) and freezing (-10°C, -20°C, -30°C and -40°C) stress between the two cultivars. The numbers of differentially expressed genes (DEGs) between the two cultivars were 1831, 2030, 1993, 1845 and 2137 under the five treatments. Functional enrichment analysis suggested that the metabolic pathway, response to stimulus and catalytic activity were significantly enriched under stronger freezing stress. Among the DEGs, nine participated in the Ca2+ signal pathway, thirty-two were identified to participate in sucrose metabolism, and others were identified to participate in the regulation of ROS, plant hormones and antifreeze proteins. In addition, important transcription factors (WRKY, AP2/ERF, NAC and bZIP) participating in freezing stress were activated under different degrees of freezing stress. Conclusions: Our research first provides a more comprehensive understanding of DEGs involved in freezing stress at the transcriptome level in two Z. jujuba cultivars with different freezing tolerances. These results may help to elucidate the molecular mechanism of freezing tolerance in jujube and also provides new insights and candidate genes for genetically enhancing freezing stress tolerance.

The Transcriptional Regulatory Mechanisms Exploration of Jujube Biological Traits through Multi-omics Analysis

“…Additionally, ZjWRKY family members, ZjAP2/ERF family members, ZjNAC family members and ZjbZIP family members in jujube were also identified and analyzed for function. Among these transcript factors, ZjDREB1 (LOC107404402) could enhance the freezing resistance of jujube by transgenic experiment verification [90]. ZjWRKY27 (LOC107426111) responded strongly to drought and salt stress, presenting itself as a candidate target gene for salt tolerance breeding [91], and ZjWRKY6 (LOC107426870) and ZjWRKY65 (LOC107435508) in 'Suanzao' was found to enhance plant salt tolerance by increasing the antioxidant enzyme activity, reducing malondialdehyde accumulation, and maintaining K + /Na + homeostasis [92].…”