Browsing by Author "Sanhueza, Dayan"

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    A novel pectin methylesterase inhibitor, PMEI3, in common bean suggests a key role of pectin methylesterification in Pseudomonas resistance
    (2024) De la Rubia, Alfonso G.; Largo-Gosens, Asier; Yusta, Ricardo; Sepulveda-Orellana, Pablo; Riveros, Anibal; Centeno, Maria Luz; Sanhueza, Dayan; Meneses, Claudio; Saez-Aguayo, Susana; Garcia-Angulo, Penelope
    The mechanisms underlying susceptibility to and defense against Pseudomonas syringae (Pph) of the common bean (Phaseolus vulgaris) have not yet been clarified. To investigate these, 15-day-old plants of the variety Rinon were infected with Pph and the transcriptomic changes at 2 h and 9 h post-infection were analysed. RNA-seq analysis showed an up-regulation of genes involved in defense/signaling at 2 h, most of them being down-regulated at 9 h, suggesting that Pph inhibits the transcriptomic reprogramming of the plant. This trend was also observed in the modulation of 101 cell wall-related genes. Cell wall composition changes at early stages of Pph infection were associated with homogalacturonan methylation and the formation of egg boxes. Among the cell wall genes modulated, a pectin methylesterase inhibitor 3 (PvPMEI3) gene, closely related to AtPMEI3, was detected. PvPMEI3 protein was located in the apoplast and its pectin methylesterase inhibitory activity was demonstrated. PvPMEI3 seems to be a good candidate to play a key role in Pph infection, which was supported by analysis of an Arabidopsis pmei3 mutant, which showed susceptibility to Pph, in contrast to resistant Arabidopsis Col-0 plants. These results indicate a key role of the degree of pectin methylesterification in host resistance to Pph during the first steps of the attack.
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    Identification of grapevine clones via high-throughput amplicon sequencing: a proof-of-concept study
    (2023) Urra, Claudio; Sanhueza, Dayan; Pavez, Catalina; Tapia, Patricio; Nunez-Lillo, Gerardo; Minio, Andrea; Miossec, Matthieu; Blanco-Herrera, Francisca; Gainza, Felipe; Castro, Alvaro; Cantu, Dario; Meneses, Claudio
    Wine cultivars are available to growers in multiple clonal selections with agronomic and enological differences. Phenotypic differences between clones originated from somatic mutations that accrued over thousands of asexual propagation cycles. Genetic diversity between grape cultivars remains unexplored, and tools to discriminate unequivocally clones have been lacking. This study aimed to uncover genetic variations among a group of clonal selections of 4 important Vitis vinifera cultivars: Cabernet sauvignon, Sauvignon blanc, Chardonnay, and Merlot, and use this information to develop genetic markers to discriminate the clones of these cultivars. We sequenced with short-read sequencing technology the genomes of 18 clones, including biological replicates for a total of 46 genomes. Sequences were aligned to their respective cultivar's reference genome for variant calling. We used reference genomes of Cabernet sauvignon, Chardonnay, and Merlot and developed a de novo genome assembly of Sauvignon blanc using long-read sequencing. On average, 4 million variants were detected for each clone, with 74.2% being single nucleotide variants and 25.8% being small insertions or deletions (InDel). The frequency of these variants was consistent across all clones. From these variants, we validated 46 clonal markers using high-throughput amplicon sequencing for 77.7% of the evaluated clones, most of them small InDel. These results represent an advance in grapevine genotyping strategies and will benefit the viticulture industry for the characterization and identification of the plant material.
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    Transcriptomic reprogramming in a susceptible Phaseolus vulgaris L. variety during Pseudomonas syringae attack: The key role of homogalacturonan methylation
    (2022) De la Rubia, Alfonso G.; Largo-Gosens, Asier; Yusta, Ricardo; Sepúlveda, Pablo; Riveros Valdevenito, Anibal Jose; Luz Centeno, María Luz; Sanhueza, Dayan; Meneses Araya, Claudio Antonio; Saez-Aguayo, Susana; García-Angulo, Penélope
    The susceptibility of common bean varieties to Pseudomonas pv. syringae phaseolicola (Pph) has been well-documented. However, the molecular mechanism that drives this susceptibility has not been clarified yet. In an attempt to understand this process, 15-day-old common bean plants, variety riñón, were infected with Pph to analyze the transcriptomic changes during the first steps of the infection (at 2 and 9 h). RNA-seq analysis showed an upregulation of defense- and signaling-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, suggesting that Pph could produce/induce changes in the CW. 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. From all HG-related genes modulated by the infection, 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 its PME inhibitory activity was demonstrated. Therefore, PvPMEI3 seems to be a good candidate to play a key role in Pph infection. This premise was supported by the analysis of Arabidopsis pmei3 mutant, which showed susceptibility to Pph, in contrast to resistant Col-0 control plants. 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 neither maintained during the necessary time, nor are deep enough to block the action of the pathogen, facilitating the well known susceptibility of riñón variety to Pph.