Transcriptomic study of pedicels from GA3-treated table grape genotypes with different susceptibility to berry drop reveals responses elicited in cell wall yield, primary growth and phenylpropanoids synthesis.

• DOI: 10.21203/rs.2.16110/v2
• Publication Date: 2019-12-17T18:38:56Z
• Authors: Marco Meneses; Miguel García-Rojas; Claudia Muñoz-Esp...; Tomás Carrasco-Va...; Bruno Defilippi; Mauricio González...; Claudio Meneses; Rodrigo Infante; Patricio Hinrichsen
• Keywords: Pedicel; Table grape; Gibberellic acid; Phenylpropanoid

Abstract Background Gibberellins (GA3) are the most sprayed growth regulator for table grape production worldwide, increasing berry size of seedless varieties through pericarp cell expansion. However, these treatments also exacerbate drop, which has a detrimental effect on postharvest quality commercialized clusters. Several studies have suggested that pedicel stiffening caused by GA3 would role in this disorder. Nevertheless, transcriptional and phenotypic information regarding responses to is minimal.Results Characterization using lines L23 Thompson Seedless showed former was up six times more susceptible drop than latter. increased diameter dry matter percentage both genotypes. Induction lignin biosynthesis-related genes been reported, so quantity polymer measured. The acetyl bromide method detected decreased concentration seven days after treatment, due higher wall yield isolated fractions GA3-treated samples dilution effect. Thus, an initial enrichment primary components response suggested, particularly background. A transcriptomic profiling performed identify were associated with changes. This analysis identified 1,281 1,787 differentially upregulated cv. Seedless, respectively. Concomitantly, 1,202 1,317 downregulated (FDR≤0.05). Gene ontology pathways including phenylpropanoids, metabolism, xylem development, photosynthesis cycle at post application. Twelve characterized qPCR striking differences observed between genotypes, mainly related synthesis.Conclusions High levels early strong synthesis promoted treatment. Genetic backgrounds can produce similar GA3, although there considerable variation regulation terms expressed, extent transcript achieved within same time frame.