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Eliminating the purple acid phosphatase At PAP 26 in Arabidopsis thaliana delays leaf senescence and impairs phosphorus remobilization
Author(s) -
Robinson Whitney D.,
Carson Ira,
Ying Sheng,
Ellis Kaya,
Plaxton William C.
Publication year - 2012
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12006
Subject(s) - senescence , arabidopsis , arabidopsis thaliana , phosphatase , biology , germination , acid phosphatase , phosphorus , mutant , phosphorus deficiency , biochemistry , enzyme , gene , botany , nutrient , chemistry , microbiology and biotechnology , organic chemistry , ecology
Summary Limitation of crop productivity by suboptimal phosphorus ( P ) nutrition is a widespread concern. Enhanced crop P ‐use efficiency could be achieved by improving P remobilization from senescing leaves to developing tissues and seeds. Transcriptomic studies indicate that hundreds of A rabidopsis thaliana genes are up‐regulated during leaf senescence, including that encoding the purple acid phosphatase (PAP) At PAP 26 (At5g34850). In this study, biochemical and functional genomic tools were integrated to test the hypothesis that At PAP 26 participates in P remobilization during leaf senescence. An eightfold increase in acid phosphatase activity of senescing leaves was correlated with the accumulation of At PAP 26 transcripts and immunoreactive At PAP 26 polypeptides. Senescing leaves of an atpap26 T‐ DNA insertion mutant displayed a > 90% decrease in acid phosphatase activity, markedly impaired P remobilization efficiency and delayed senescence. This was paralleled by reduced seed total P concentrations and germination rates. These results demonstrate that At PAP 26 loss of function causes dramatic effects that cannot be compensated for by any other PAP isozyme, even though Arabidopsis contains 29 different PAP genes. Our current and earlier studies establish that At PAP 26 not only helps to scavenge P from organic P sources when Arabidopsis is cultivated in inorganic orthophosphate ( P i)‐deficient soils, but also has an important P remobilization function during leaf senescence.