Abscisic acid enhances storability of winter jujube by regulating cell wall and phenylpropane metabolisms during cold storage

Abstract

Winter jujube is extremely susceptible to softening and reddening after harvest, resulting in serious quality deterioration. The influences of abscisic acid (ABA) on the storage quality, cell wall metabolism, phenylpropane metabolism, and differentially expressed genes of winter jujube were investigated. The results showed that low concentration of ABA (0.2 mmol L−1) treatment maintained the firmness and greenness of winter jujube, while inhibiting respiration rate and ethylene production after harvest. Compared with control group, ABA treatment inhibited the activities of pectin methylesterase, polygalacturonase, β-1,3-glucanase, α-l-arabinofurosidase, and phenylalanine ammonia-lyase, but improved the activities of cinnamate-4-hydroxylase, 4-coumaric acid CoA ligase, and chalcone synthase. Transcriptome analysis revealed a total of 13,068 differentially expressed genes among control (0 d and 30 d) and ABA (30 d) groups, which were enriched in the phenylpropanoid metabolism, secondary metabolic biosynthesis, and plant hormone signal transduction pathways. In addition, ABA regulated 33, 29, 35, and 30 genes involved in cell wall metabolism, phenylpropane metabolism, plant hormone signal transduction, and related transcription factors respectively, thereby inhibiting softening and reddening, and delaying ripening and senescence to ultimately maintain the storage quality in winter jujube. These results supply a theoretical basis for investigating postharvest biology and developing storage and preservation techniques of winter jujube.