Class III Peroxidases PRX01, PRX44, and PRX73 Control Root Hair Growth in Arabidopsis thaliana

CECILIA BORASSI; ARIEL APTEKMANN; PAEZ-VALENCIA JULIO; YOSSMAYER DEL CARMEN RONDON GUERRERO; MISHLER-ELMORE JOHN W; BEDINGER PATRICIA; ALEJANDRO NADRA; JOSE M. ESTEVEZ; ELIANA MARZOL; PHILIPPE RANOCHA; JANICE PENNINGTON; DIANA R. RODRIGUEZ GARCIA; FLEMING MARGARET; FRANCISCA BLANCO-HERRERA; LUCIANA CAPECE; MARISA OTEGUI; MARIANA CARIGNANI SARDOY; MAURO BRINGAS; JAVIER MARTINEZ-PACHECO; JUAN MANUEL PERALTA; SILVINA MANGANO; CHRISTOPHE DUNAND; MICHAEL HELD

INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES

MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL-MDPI

Año: 2022 vol. 23

1422-0067

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.