Gibberellin-induced changes in the transcriptome of grapevine (Vitis labrusca x V-vinifera) cv. Kyoho flowers

Background: Gibberellins are well known for their growth control function in flower, fruit and seed development, and as such, exogenous gibberellic acid (GA) application plays an important role in viticulture. Unfortunately, the mechanism by which GA(3) acts in the regulation of these complicated developmental processes in grape remains unclear. Results: In the present study, we demonstrated that application of GA(3) to 'Kyoho' grapevine inflorescences at pre-bloom promoted flower opening, and induced fruit coloring as well as seed abortion. In an attempt to obtain a deeper understanding of the molecular mechanisms driving these responses to GA(3) treatment, we performed large-scale transcriptome sequencing of grape flowers following GA(3) treatment using Illumina sequencing technology. Global expression profiles of GA(3)-treated and untreated grape flowers were compared and a large number of GA(3)-responsive genes were identified. Gene ontology (GO) term classification and biochemical pathway analyses indicated that GA(3) treatment caused changes in the levels of transcripts involved in cellular processes, reproduction, hormone and secondary metabolism, as well as the scavenging and detoxification of reactive oxygen species (ROS). These findings suggest that GA(3)-induced morphological alterations may be related to the control of hormone biosynthesis and signaling, regulation of transcription factors, alteration of secondary metabolites, and the stability of redox homeostasis. Conclusions: Taken together, this comprehensive inflorescence transcriptome data set provides novel insight into the response of grape flowers to GA(3) treatment, and also provides possible candidate genes or markers that could be used to guide future efforts in this field.