title: ß-amylase1 mutant Arabidopsis plants show improved drought tolerance due to reduced starch breakdown in guard cells.
abstract: In plants, drought stress is a major growth limiting factor causing cell water loss through open stomata. In this study, guard cell-specific transcripts from drought-stressed Arabidopsis plants were analysed and a down-regulation of β-amylase 1 (BAM1) was found. In previous studies, BAM1 was shown to be involved in stomatal starch degradation under ambient conditions. Impaired starch breakdown of bam1 mutant plants was accompanied by decreased stomatal opening. Here, it is shown that drought tolerance of bam1 mutant plants is improved as compared with wild-type controls. Microarray analysis of stomata-specific transcripts from bam1 mutant plants revealed a significant down-regulation of genes encoding aquaporins, auxin- and ethylene-responsive factors, and cell-wall modifying enzymes. This expression pattern suggests that reduced water uptake and limited cell wall extension are associated with the closed state of stomata of bam1 mutant plants. Together these data suggest that regulation of stomata-specific starch turnover is important for adapting stomata opening to environmental needs and its breeding manipulation may result in drought tolerant crop plants.
authors.affiliation: Biochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, Staudtstrasse 5, 91058 Erlangen, Germany.
authors.forename: Christian Maximilian
authors.initials: CM
authors.lastname: Prasch
authors.affiliation: Biochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, Staudtstrasse 5, 91058 Erlangen, Germany.
authors.forename: Kirsten Verena
authors.initials: KV
authors.lastname: Ott
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Biocenter, University of Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany.
authors.forename: Hubert
authors.initials: H
authors.lastname: Bauer
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Biocenter, University of Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Ache
authors.affiliation: Institute for Molecular Plant Physiology and Biophysics, Biocenter, University of Wuerzburg, Julius-von-Sachs-Platz 2, 97082 Wuerzburg, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Hedrich
authors.affiliation: Biochemistry Division, Department of Biology, Friedrich-Alexander-University Erlangen-Nuernberg, Staudtstrasse 5, 91058 Erlangen, Germany uwe.sonnewald@fau.de.
authors.forename: Uwe
authors.initials: U
authors.lastname: Sonnewald
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D013213:Starch / Q000378:metabolism*; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D014867:Water; D013213:Starch; C519658:BAM1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: Arabidopsis; drought; guard cells; starch.; β-amylases