Comparative Transcriptomic Analysis of Vernalization- and Cytokinin-Induced Floral Transition in Dendrobium nobile

Abstract

Vernalization is required for floral initiation in Dendrobium. Interestingly, those beneficial effects can also be achieved by exogenous cytokinin application in greenhouses. Thus, an as yet unknown crosstalk/interaction may exist between vernalization and cytokinin signaling pathways. In this study, we showed, by de novo transcriptome assembly using RNA-seq data from both vegetative and reproductive tissue samples, that some floral transition-related genes—DnVRN1, FT, SOC1, LFY and AP1—were differentially expressed in low-temperature-challenged (LT) or thidiazuron (TDZ)-treated plants, compared to those mock-treated (CK). Both LT and TDZ upregulated SOC1, LFY and AP1, while the upregulation of DnVRN1 and FT was only LT-induced. We further found that LT promoted the upregulation of some key cytokinin signaling regulators, including several cytokinin biosynthesis-related genes and type-B response regulator (RR)-encoding genes, and that both LT and TDZ triggered the significant upregulation of some marker genes in the gibberellin (GA) signaling pathway, indicating an important low temperature-cytokinin-GA axis in flowering. Our data thus have revealed a cytokinin-GA signal network underlying vernalization, providing a novel insight into further investigation of the molecular mechanism of floral initiation in Dendrobium.

An Integrative Analysis of Transcriptome, Proteome and Hormones Reveals Key Differentially Expressed Genes and Metabolic Pathways Involved in Flower Development in Loquat

“…Previously, transcriptomic analysis of flower development demonstrated that floral organ development is regulated by GA signaling in Gerbera hybrida [60]. In Dendrobium nobile, comparative transcriptomic analysis revealed that DEGs of GA signaling pathways are involved in floral transition [61]. These previous studies and our data suggest that key genes of GA signaling and metabolism pathways are associated with flower bud differentiation.…”

Comparative transcriptome analysis of nonchilled, chilled, and late-pink bud reveals flowering pathway genes involved in chilling-mediated flowering in blueberry

“…Transcriptome analysis is an effective approach to study flowering pathway genes [ 23 , 24 ]. Using this approach, DEGs in response to vernalization have been identified in Japanese pear ( Pyrus pyrifolia Nakai) and oriental lily [ 24 ].…”

Floral Induction and Flower Development of Orchids

“…Based on expression analyses and functional studies with heterologous expression systems, candidate genes for flowering regulatory networks in orchids have been reported. Recently, genome-wide analyses have also been taken into consideration for the identification of Orchidaceae-specific and/or species-specific key genes controlling flowering/flower development of orchids (Huang et al, 2016; Lin et al, 2016; Wen et al, 2017).…”

“…Expression of DOMADS1 was up-regulated in transgenic plants harboring p 35S : antisense DOH1 suggesting that DOH1 is a possible upstream repressor of DOMADS1 in the flowering control of Dendrobium orchids. Recently, transcriptomes of D. nobile were analyzed under cold (4 °C) or exogenous cytokinin (thidiazuron) treatment (Wen et al, 2017). The results showed that SOC1 , LFY and AP1 genes were induced by both low temperature and thidiazuron treatment whereas DnVRN1 and FT were induced only by cold treatment.…”