Examinando por Autor "Borassi, Cecilia"
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Ítem Arabidopsis RAD23B regulates pollen development by mediating degradation of KRP1(Oxford University Press, 2020-07-06) Li, Lan; Li, Bin; Xie, Chong; Zhang, Teng; Borassi, Cecilia; Estevez, José M.; Li, Xiushan; Liu, XuanmingThe ubiquitin (Ub)/26S proteasome system (UPS) plays a key role in plant growth, development, and survival by directing the turnover of numerous regulatory proteins. In the UPS, the ubiquitin-like (UBL) and ubiquitin-associated (UBA) domains function as hubs for ubiquitin-mediated protein degradation. Radiation sensitive 23 (RAD23), which has been identified as a UBL/UBA protein, contributes to the progression of the cell cycle, stress responses, ER proteolysis, and DNA repair. Here, we report that pollen development is arrested at the microspore stage in a rad23b null mutant. We demonstrate that RAD23B can directly interact with KIP-related protein 1 (KRP1) through its UBL-UBA domains. In addition, plants overexpressing KRP1 have defects in pollen development, which is a phenotype similar to the rad23b mutant. RAD23B promotes the degradation of KRP1 in vivo, which is accumulated following treatment with the proteasome inhibitor MG132. Our results indicate that RAD23B plays an important in pollen development by controlling the turnover of the key cell cycle protein, KRP1.Ítem Class III Peroxidases PRX01, PRX44, and PRX73 Control Root Hair Growth in Arabidopsis thaliana(MDPI, 2022-05-02) Marzol, Eliana; Borassi, Cecilia; Carignani Sardoy, Mariana; Ranocha, Philippe; Aptekmann, Ariel A.; Bringas, Mauro; Pennington, Janice; Paez-Valencia, Julio; Martínez Pacheco, Javier; Rodríguez-Garcia, Diana R.; Rondón Guerrero, Yossmayer Del Carmen; Peralta, Juan Manuel; Fleming, Margaret; Mishler-Elmore, John W.; Mangano, Silvina; Blanco-Herrera, Francisca; Bedinger, Patricia A.; Dunand, Christophe; Capece, Luciana; Nadra, Alejandro D.; Held, Michael; Otegui, Marisa S.; Estevez, José M.Root hair cells are important sensors of soil conditions. They grow towards and absorb water-soluble nutrients. This fast and oscillatory growth is mediated by continuous remodeling of the cell wall. Root hair cell walls contain polysaccharides and hydroxyproline-rich glycoproteins, including extensins (EXTs). Class-III peroxidases (PRXs) are secreted into the apoplastic space and are thought to trigger either cell wall loosening or polymerization of cell wall components, such as Tyr-mediated assembly of EXT networks (EXT-PRXs). The precise role of these EXT-PRXs is unknown. Using genetic, biochemical, and modeling approaches, we identified and characterized three root-hair-specific putative EXT-PRXs, PRX01, PRX44, and PRX73. prx01,44,73 triple mutation and PRX44 and PRX73 overexpression had opposite effects on root hair growth, peroxidase activity, and ROS production, with a clear impact on cell wall thickness. We use an EXT fluorescent reporter with contrasting levels of cell wall insolubilization in prx01,44,73 and PRX44-overexpressing background plants. In this study, we propose that PRX01, PRX44, and PRX73 control EXT-mediated cell wall properties during polar expansion of root hair cells. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.