Ripening is one of the key processes associated with the development of major organoleptic characteristics of the fruit. This process has been extensively characterized in climacteric fruit, in contrast with non-climacteric fruit such as grape, where the process is less understood. With the aim of studying changes in gene expression during ripening of non-climacteric fruit, an Illumina based RNA-Seq transcriptome analysis was performed on four developmental stages, between veraison and harvest, on table grapes berries cv Thompson Seedless. Functional analysis showed a transcriptional increase in genes related with degradation processes of chlorophyll, lipids, macromolecules recycling and nucleosomes organization; accompanied by a decrease in genes related with chloroplasts integrity and amino acid synthesis pathways. It was possible to identify several processes described during leaf senescence, particularly close to harvest. Before this point, the results suggest a high transcriptional activity associated with the regulation of gene expression, cytoskeletal organization and cell wall metabolism, which can be related to growth of berries and firmness loss characteristic to this stage of development. This high metabolic activity could be associated with an increase in the transcription of genes related with glycolysis and respiration, unexpected for a non-climacteric fruit ripening.

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The molecular mechanism that drives the resistance/susceptibility of common bean to Pseudomonas syringae pv. phaseolicola (Pph) has not been clarified yet. For this purpose, 15-day-old common bean plants, variety riñón, were infected with Pph to analyze the transcriptomic changes at 2 and 9 h. RNA-seq analysis showed an upregulation of defense-related genes at 2h, most of them being downregulated at 9h, suggesting that Pph would inhibit the transcriptomic reprogramming of the plant. This trend was also observed in the modulation of 101 cell wall (CW) related genes. However, the changes in CW composition at early stages of Pph infection were related to homogalacturonan (HG) methylation and the formation of HG egg boxes. A common bean pectin methylesterase inhibitor 3 (PvPMEI3) gene - closely related to AtPMEI3 - was detected. In addition, PMEI3 protein was located in the apoplast and had inhibitory activity. Therefore, PvPMEI3 seems to be a good candidate to play a key role in infection, because Arabidopsis pmei3 mutant showed susceptibility to Pph. All these changes could be an attempt to reinforce the CW structure and thus, hinder the attack of the bacterium. However, these transcriptional and CW-remodeling processes are not deep enough to block the action of the pathogen.