Abstract

The Class III peroxidases (CIII Prxs) belong to a plant-specific multigene family. Thanks to their double catalytic cycle they can oxidize compounds or release reactive oxygen species (ROS). They are either involved in different cell wall stiffening processes such as lignification and suberization, in cell wall loosening or defense mechanisms. Germination is an important developmental stage requiring specific peroxidase activity. However, lithe is known about which isoforms are involved. Five CIII Prx encoding genes: AtPrx04, AtPrx16, AtPrx62, AtPrx69, and AtPrx71 were identified from published microarray data mining. Delayed or induced testa and endosperm rupture were observed for the corresponding CIII Prx mutant lines indicating either a gene-specific inducing or repressing role during germination, respectively. Via in situ hybridization AtPrx16, AtPrx62, AtPrx69 and AtPrx71 transcripts were exclusively localized to the micropylar endosperm facing the radicle, and transcriptomic data analysis enabled positioning the five CIII Prxs in a co-expression network enriched in germination, cell wall, cell wall proteins and xyloglucan hits. Evidence were produced showing that the five CIII Prxs were cell wall-targeted proteins and that the micropylar endosperm displayed a complex cell wall domain topochemistry. Finally, we drew a spatio-temporal model highlighting the fine sequential gene expression and the possible involvement of micropylar endosperm cell wall domains to explain the non-redundant cell wall stiffening and loosening functions of the CIII Prxs in a single cell type. We also highlighted the necessity of a peroxidase homeostasis to accurately control the micropylar endosperm cell wall dynamics during Arabidopsis germination events.

Keywords

Arabidopsis; Class III peroxidase; Testa rupture; Micropylar endosperm rupture; Germination; Cell wall domain remodeling

Published in

Plant Science
2020, Volume: 298, article number: 110565
Publisher: ELSEVIER IRELAND LTD

SLU Authors

• Raggi, Sara

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Biochemistry and Molecular Biology
Botany


Publication identifier

DOI: https://doi.org/10.1016/j.plantsci.2020.110565

Permanent link to this page (URI)

https://res.slu.se/id/publ/107330