Transcriptome profiling of Gerbera hybrida reveals that stem bending is caused by water stress and regulation of abscisic acid

Abstract

Background Gerbera hybrida is one of the most popular cut flowers in the world; however, stem bending, which always happens when gerbera flower harvested from the field, greatly limits its vase life. To date the molecular mechanisms underlying stem bending remain poorly understood. Results In this study, we performed high-throughput transcriptome sequencing of gerbera during stem bending using the Illumina sequencing technology. Three cDNA libraries constructed from mRNAs of gerbera stem at stem bending stage 0, 2 and 4 were sequenced. More than 300 million high-quality reads were generated and assembled into 96,492 unigenes. Among them, 34,166 unigenes were functionally annotated based on similarity search with known protein. Sequences derived from plants at different stem bending stages were mapped to the assembled transcriptome, and 9,406 differentially expressed genes (DEGs) were identified. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, specific pathways were identified during the stem bending process, such as phenylpropanoid biosynthesis pathway, phenylalanine metabolism pathway, starch and sucrose metabolism pathway, and plant hormone signal transduction pathway. A total of 211 transcription factors (TFs), including TF families involved in plant senescence, such as NAC, MYB, WRKY, and AP2/ERF members, as well as TFs related to water stress tolerance, were shown to be regulated during stem bending. Gene Onotology (GO) functional enrichment analysis indicated that key genes involved in responses to osmotic and oxidative stresses were also varied in expression during this process. Furthermore, analysis of DEGs involved in the hormone signaling pathways and determination of endogenous abscisic acid (ABA) content showed that stem bending may be an ethylene-independent process, but regulated by ABA. In short, our findings suggested that the stem bending of cut gerbera may be caused by the involvement of water stress and regulation of ABA during the postharvest life. Conclusions The transcriptome sequences provide a valuable resource in revealing the molecular mechanism underlying stem bending of cut flower and offer novel genes that can be used to guide future studies for ornamental plant breeding. Electronic supplementary material The online version of this article (10.1186/s12864-019-5961-1) contains supplementary material, which is available to authorized users.

Organ-Specific Transcriptome Analysis Identifies Candidate Genes Involved in the Stem Specialization of Bermudagrass (Cynodon dactylon L.)

“…Considering that plant hormone signal transduction were also significantly enriched with DEGs in three types of stems ( Figure 5 ), in combination with the important regulatory roles of phytohormone in stem growth and development ( Gamuyao et al, 2017 ; Ge et al, 2019 ), we thoroughly analyzed the expression profile of 401 DEGs participating in plant hormone signal transduction. Among the 401 DEGs, 89, 41, 33, 71, 30, 31, 59, and 47 DEGs were annotated as auxin, cytokinine, gibberellin, abscisic acid, ethylene, brassinosteroid, jasmonic acid (JA), and salicylic acid signal transduction-related genes, respectively.…”

Sequencing and analysis of gerbera daisy leaf transcriptomes reveal disease resistance and susceptibility genes differentially expressed and associated with powdery mildew resistance

“…RNA-seq is independent of pre-existing databases of expressed genes and therefore can be used to construct an unbiased profile of gerbera gene expression in relation to PM. Previously RNA-seq has been used in gerbera to profile transcriptome changes in response to physiological disorders and biotic and abiotic stresses, including stem bending, Botrytis infection, and cold stresses [ 23 , 27 , 30 ]. While the PM resistance has been transferred to new cultivars developed by the University of Florida using the resistance source UFGE 4033, the cultivar development process relied on classical breeding and PM screening.…”

“…Primers used in the RT-qPCR experiment were designed using primer3 software ( https://bioinfo.ut.ee/primer3-0.4.0/ ) and are listed in Table S 9 . Primers for the actin gene in gerbera was used from Ge et al, and Kuang et al [ 27 , 78 ]. The expressions of the target genes were normalized to an endogenous G. hybrida actin gene and relative expressions were calculated using 2 {−Ct(gene of interest)-Ct(actin)} [ 79 ].…”

“…For a long time, genomic resources in gerbera were limited to some expressed sequence tags (ESTs) [ 26 ]. Recently, RNA-seq studies have been conducted to understand gene expression associated with gerbera flower traits, stem bending and Botrytis resistance [ 23 , 27 ]. So far, there has not been any study in gerbera to understand gene expression in response to PM.…”

Identification of WRKY transcription factors associated with leaf and corolla senescence in Petunia hybrida

“…Therefore, similarities in the signalling mechanisms triggering senescence in leaves and petals are expected (Price et al 2008;Wagstaff et al 2009). Although changes in gene expression of WRKYs have been described during the progression of petal senescence in several species, no members have been reported to regulate age-related or pollination-induced petal senescence yet (Price et al 2008;Wagstaff et al 2009;Tsanakas et al 2014;Trivellini et al 2016;Chen et al 2018;Wang et al 2018;Wang et al 2019;Ge et al 2019;Wang et al 2020).…”