Transcriptomic Analysis Reveals Key Candidate Genes Related to Seed Abortion in Chinese Jujube (Ziziphus jujuba Mill)

Background: Seed abortion is a common phenomenon in Chinese jujube that seriously hinders the process of cross-breeding. However, the molecular mechanisms of seed abortion remain unclear in jujube. Methods: Here, we performed transcriptome sequencing using eight flower and fruit tissues at different developmental stages in Ziziphus jujuba Mill. ‘Zhongqiusucui’ to identify key genes related to seed abortion. Histological analysis revealed a critical developmental process of embryo abortion after fertilization. Results: Comparisons of gene expression revealed a total of 14,012 differentially expressed genes. Functional enrichment analyses of differentially expressed genes between various sample types uncovered several important biological processes, such as embryo development, cellular metabolism, and stress response, that were potentially involved in the regulation of seed abortion. Furthermore, gene co-expression network analysis revealed a suite of potential key genes related to ovule and seed development. We focused on three types of candidate genes, agamous subfamily genes, plant ATP-binding cassette subfamily G transporters, and metacaspase enzymes, and showed that the expression profiles of some members were associated with embryo abortion. Conclusion: This work generates a comprehensive gene expression data source for unraveling the molecular mechanisms of seed abortion and aids future cross-breeding efforts in jujube.