title: Transcriptional response of Arabidopsis seedlings during spaceflight reveals peroxidase and cell wall remodeling genes associated with root hair development.
abstract: •
  
  
  OBJECTIVE
  Plants will be an important component of advanced life support systems during space exploration missions. Therefore, understanding their biology in the spacecraft environment will be essential before they can be used for such systems.•
  
  
  METHODS
  Seedlings of Arabidopsis thaliana were grown for 2 wk in the Biological Research in Canisters (BRIC) hardware on board the second to the last mission of the space shuttle Discovery (STS-131). Transcript profiles between ground controls and space-grown seedlings were compared using stringent selection criteria.•
  
  
  RESULTS
  Expression of transcripts associated with oxidative stress and cell wall remodeling was repressed in microgravity. These downregulated genes were previously shown to be enriched in root hairs consistent with seedling phenotypes observed in space. Mutations in genes that were downregulated in microgravity, including two uncharacterized root hair-expressed class III peroxidase genes (PRX44 and PRX57), led to defective polar root hair growth on Earth. PRX44 and PRX57 mutants had ruptured root hairs, which is a typical phenotype of tip-growing cells with defective cell walls and those subjected to stress.•
  
  
  CONCLUSIONS
  Long-term exposure to microgravity negatively impacts tip growth by repressing expression of genes essential for normal root hair development. Whereas changes in peroxidase gene expression leading to reduced root hair growth in space are actin-independent, root hair development modulated by phosphoinositides could be dependent on the actin cytoskeleton. These results have profound implications for plant adaptation to microgravity given the importance of tip growing cells such as root hairs for efficient nutrient capture.
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA.
authors.forename: Taegun
authors.initials: T
authors.lastname: Kwon
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA.
authors.forename: J Alan
authors.initials: JA
authors.lastname: Sparks
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Nakashima
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA.
authors.forename: Stacy N
authors.initials: SN
authors.lastname: Allen
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401 USA.
authors.forename: Elison B
authors.initials: EB
authors.lastname: Blancaflor
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D005786:Gene Expression Regulation; D018384:Oxidative Stress; D010544:Peroxidases / Q000235:genetics* / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013026:Space Flight; D014893:Weightlessness
chemical_list: D029681:Arabidopsis Proteins; D010544:Peroxidases; C574008:PRX33 protein, Arabidopsis
keywords: Arabidopsis thaliana; Brassicaceae; actin; cell wall; microgravity; oxidative stress; peroxidase; root hairs; spaceflight; tip growth