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PIPKs are essential for rhizoid elongation and caulonemal cell development in the moss Physcomitrella patens.

Saavedra, Laura LU ; Balbi, Virginia LU ; Lerche, Jennifer; Mikami, Koji; Heilmann, Ingo and Sommarin, Marianne LU (2011) In Plant Journal 67. p.635-647
Abstract
PtdIns-4,5-bisphosphate is a lipid messenger of eukaryotic cells playing critical roles in processes such as cytoskeleton organization, intracellular vesicular trafficking, secretion, cell motility, regulation of ion channels and nuclear signalling pathways. The enzymes responsible for the synthesis of PtdIns(4,5)P(2) are phosphatidylinositol phosphate kinases (PIPKs). The moss Physcomitrella patens contains two PIPKs, PpPIPK1 and PpPIPK2. To study their physiological role, both genes were disrupted by targeted homologous recombination and as a result mutant plants with lower PtdIns(4,5)P(2) levels were obtained. A strong phenotype for pipk1, but not for pipk2 single knockout lines, was obtained. The pipk1 knockout lines were impaired in... (More)
PtdIns-4,5-bisphosphate is a lipid messenger of eukaryotic cells playing critical roles in processes such as cytoskeleton organization, intracellular vesicular trafficking, secretion, cell motility, regulation of ion channels and nuclear signalling pathways. The enzymes responsible for the synthesis of PtdIns(4,5)P(2) are phosphatidylinositol phosphate kinases (PIPKs). The moss Physcomitrella patens contains two PIPKs, PpPIPK1 and PpPIPK2. To study their physiological role, both genes were disrupted by targeted homologous recombination and as a result mutant plants with lower PtdIns(4,5)P(2) levels were obtained. A strong phenotype for pipk1, but not for pipk2 single knockout lines, was obtained. The pipk1 knockout lines were impaired in rhizoid and caulonemal cell elongation, whereas pipk1-2 double knockout lines showed dramatic defects in protonemal and gametophore morphology manifested by the absence of rapidly elongating caulonemal cells in the protonemal tissue, leafy gametophores with very short rhizoids, and loss of sporophyte production. pipk1 complemented by overexpression of PpPIPK1 fully restored the wild type phenotype whereas overexpression of the inactive PpPIPK1E885A did not. Overexpression of PpPIPK2 in the pipk1-2 double knockout did not restore the wild type phenotype demonstrating that PpPIPK1 and PpPIPK2 are not functionally redundant. In vivo imaging of the cytoskeleton network revealed that the shortened caulonemal cells in the pipk1 mutants was the result of the absence of the apicobasal gradient of cortical F-actin cables normally observed in wild type caulonemal cells. Our data indicate that both PpPIPKs play a crucial role in the development of the moss P. patens, and particularly in the regulation of tip growth. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Plant Journal
volume
67
pages
635 - 647
publisher
Wiley-Blackwell
external identifiers
  • wos:000293753800006
  • pmid:21554449
  • scopus:80051672107
ISSN
1365-313X
DOI
10.1111/j.1365-313X.2011.04623.x
language
English
LU publication?
yes
id
b73bfb92-70d0-42c7-bd47-7f4db7f812d9 (old id 1973060)
date added to LUP
2011-06-21 17:30:49
date last changed
2017-10-01 04:05:24
@article{b73bfb92-70d0-42c7-bd47-7f4db7f812d9,
  abstract     = {PtdIns-4,5-bisphosphate is a lipid messenger of eukaryotic cells playing critical roles in processes such as cytoskeleton organization, intracellular vesicular trafficking, secretion, cell motility, regulation of ion channels and nuclear signalling pathways. The enzymes responsible for the synthesis of PtdIns(4,5)P(2) are phosphatidylinositol phosphate kinases (PIPKs). The moss Physcomitrella patens contains two PIPKs, PpPIPK1 and PpPIPK2. To study their physiological role, both genes were disrupted by targeted homologous recombination and as a result mutant plants with lower PtdIns(4,5)P(2) levels were obtained. A strong phenotype for pipk1, but not for pipk2 single knockout lines, was obtained. The pipk1 knockout lines were impaired in rhizoid and caulonemal cell elongation, whereas pipk1-2 double knockout lines showed dramatic defects in protonemal and gametophore morphology manifested by the absence of rapidly elongating caulonemal cells in the protonemal tissue, leafy gametophores with very short rhizoids, and loss of sporophyte production. pipk1 complemented by overexpression of PpPIPK1 fully restored the wild type phenotype whereas overexpression of the inactive PpPIPK1E885A did not. Overexpression of PpPIPK2 in the pipk1-2 double knockout did not restore the wild type phenotype demonstrating that PpPIPK1 and PpPIPK2 are not functionally redundant. In vivo imaging of the cytoskeleton network revealed that the shortened caulonemal cells in the pipk1 mutants was the result of the absence of the apicobasal gradient of cortical F-actin cables normally observed in wild type caulonemal cells. Our data indicate that both PpPIPKs play a crucial role in the development of the moss P. patens, and particularly in the regulation of tip growth.},
  author       = {Saavedra, Laura and Balbi, Virginia and Lerche, Jennifer and Mikami, Koji and Heilmann, Ingo and Sommarin, Marianne},
  issn         = {1365-313X},
  language     = {eng},
  pages        = {635--647},
  publisher    = {Wiley-Blackwell},
  series       = {Plant Journal},
  title        = {PIPKs are essential for rhizoid elongation and caulonemal cell development in the moss Physcomitrella patens.},
  url          = {http://dx.doi.org/10.1111/j.1365-313X.2011.04623.x},
  volume       = {67},
  year         = {2011},
}