Abstract:
Background: The Arabidopsis thaliana CONSTITUTIVE EXPRESSOR OF PATHOGENESIS-RELATED
GENES5 (CPR5) gene has been previously implicated in disease resistance, cell proliferation, cell
death, and sugar sensing, and encodes a putative membrane protein of unknown biochemical
function. Trichome development is also affected in cpr5 plants, which have leaf trichomes that are
reduced in size and branch number.
Results: In the work presented here, the role of CPR5 in trichome development was examined.
Trichomes on cpr5 mutants had reduced birefringence, suggesting a difference in cell wall structure
between cpr5 and wild-type trichomes. Consistent with this, leaf cell walls of cpr5 plants contained
significantly less paracrystalline cellulose and had an altered wall carbohydrate composition. We
also found that the effects of cpr5 on trichome size and endoreplication of trichome nuclear DNA
were epistatic to the effects of mutations in triptychon (try) or overexpression of GLABRA3,
indicating that these trichome developmental regulators are dependant on CPR5 function for their
effects on trichome expansion and endoreplication.
Conclusion: Our results suggest that CPR5 is unlikely to be a specific regulator of pathogen
response pathways or senescence, but rather functions either in cell wall biogenesis or in multiple
cell signaling or transcription response pathways.
Description:
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
