A PIIB-type Ca2+-ATPase is essential for stress adaptation in Physcomitrella patens.
Transient cytosolic Ca(2+) ([Ca(2+)](cyt)) elevations are early events in plant signaling pathways including those related to abiotic stress. The restoration of [Ca(2+)](cyt) to prestimulus levels involves ATP-driven Ca(2+) pumps, but direct evidence for an essential role of a plant Ca(2+)-ATPase in abiotic stress adaptation is missing. Here, we report on a stress-responsive Ca(2+)-ATPase gene (PCA1) from the moss Physcomitrella patens. Functional analysis of PCA1 in a Ca(2+) transport-deficient yeast mutant suggests that PCA1 encodes a P(IIB)-type Ca(2+)-ATPase harboring an N-terminal autoinhibitory domain. In vivo localizations identified membranes of small vacuoles as the integration site for a PCA1:GFP fusion protein. PCA1 mRNA levels are up-regulated by dehydration, NaCl, and abscisic acid, and PCA1 loss-of-function mutants (DeltaPCA1) exhibit an enhanced susceptibility to salt stress. The DeltaPCA1 lines show sustained elevated [Ca(2+)](cyt) in response to salt treatment in contrast to WT that shows transient Ca(2+) elevations, indicating a direct role for PCA1 in the restoration of prestimulus [Ca(2+)](cyt). The altered Ca(2+) response of the DeltaPCA1 mutant lines correlates with altered expression levels of stress-induced genes, suggesting disturbance of a stress-associated signaling pathway. We propose that PCA1 is an essential component for abiotic stress adaptation in Physcomitrella involved in the generation of a specific salt-induced Ca(2+) signature.
Qudeimat
Enas
E
Plant Biotechnology, Institute of Biology II, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany.
Faltusz
Alexander M C
AM
Wheeler
Glen
G
Lang
Daniel
D
Holtorf
Hauke
H
Brownlee
Colin
C
Reski
Ralf
R
Frank
Wolfgang
W
D000040:Abscisic Acid / Q000494:pharmacology; D019068:Bryopsida / Q000201:enzymology* / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000235:genetics* / Q000378:metabolism*; D003890:Desiccation; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009997:Osmotic Pressure; D030821:Plants, Genetically Modified; D012441:Saccharomyces cerevisiae; D055049:Salt Tolerance / Q000502:physiology; D012492:Salts / Q000494:pharmacology; D013312:Stress, Physiological / Q000502:physiology*; D014617:Vacuoles / Q000201:enzymology
D012492:Salts; D000040:Abscisic Acid; D000252:Calcium-Transporting ATPases; D002118:Calcium