Physiological and transcriptomic comparasions provide insights into the coordinated mechanisms of Dendrobium spp in response to cold stress

Abstract

Abstract Background Dendrobium spp is an tropical orchid with ornamental and medicinal value. Dendrobium spp is sensitive to low temperature, and the underlying cold–response regulatory mechanisms are unclear. Here, we compared the transcriptomic responses to cold stress of the cold–tolerant cultivar ‘Hongxing’ (HX) and the cold–sensitive cultivar ‘Sonia Hiasakul’ (SH). Results The chemometric results showed that the physiological response of SH in the later cold period was similar to that of HX during the entire period. The orthogonal partial least squares discriminant analysis (OPLS–DA) showed that soluble proteins (SP) and POD were key physiological parameters for assessing the cold tolerance of two Dendrobium spp cultivars. The weighted gene co–expression network analysis (WGCNA) results showed that many cold response genes and metabolic pathways significantly associated with physiological indices were enriched in the 11 modules. The KEGG and GO enrichment analysis of the 105 hub genes showed that Dendrobium spp could adapt to cold stress by regulating signal transduction, plant hormones, transcription factors, protein translation and modification, functional proteins, biosynthesis and metabolism, cell structure, light and circadian clocks. Among them, the hub genes of the cold response network include signal transduction–remorin gene pp34, signal transduction–ABA pathway–related genes PP2C, SnRK2, ABF1 and SKIP17, Ca2+ signaling–related gene CRSH1, carbohydrate–related gene SS2, cell wall synthesis gene CAD7, and endocytosis–related gene VPS52A. Conclusion The cold–responsive genes and metabolic pathways of Dendrobium spp revealed in this study may contribute to further investigation of the mechanisms of the cold–tolerance genetic enhancement, and cold–resistance breeding in related plants.