Class III peroxidases PRX01, PRX44, and PRX73 potentially target extensins during root hair growth in Arabidopsis thaliana

• Published in: International journal of molecular sciences 2022-05, Vol.23 (10)
• Main Authors: Marzol, Eliana, Borassi, Cecilia, Sardoy, Mariana Carignani, Ranocha, Philippe, Aptekman, Ariel A, Bringas, Mauro, Pennington, Janice, Paez-Valencia, Julio, Pacheco, Javier Martínez, 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, Dunand, Christophe, Capece, Luciana, Nadra, Alejandro D, Held, Michael, Otegui, Marisa S, Estevez, José M
• Format: Article
• Language: English
• Subjects: Life Sciences
• ISSN: 1661-6596; 1422-0067
• DOI: 10.3390/ijms23105375

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