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Enzyme activities of A rabidopsis inositol polyphosphate kinases A t IPK 2α and A t IPK 2β are involved in pollen development, pollen tube guidance and embryogenesis
Author(s) -
Zhan Huadong,
Zhong Yujiao,
Yang Zhongnan,
Xia Huijun
Publication year - 2015
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12846
Subject(s) - biology , mutant , pollen tube , gametophyte , inositol , kinase , microbiology and biotechnology , biochemistry , pollen , botany , receptor , gene , pollination
Summary Inositol polyphosphate kinase ( IPK 2) is a key component of inositol polyphosphate signaling. There are two highly homologous inositol polyphosphate kinases ( A t IPK 2α and A t IPK 2β) in A rabidopsis. Previous studies that overexpressed or reduced the expression of A t IPK 2α and At IPK 2β revealed their roles in auxiliary shoot branching, abiotic stress responses and root growth. Here, we report that A t IPK 2 α and A t IPK 2 β act redundantly during pollen development, pollen tube guidance and embryogenesis. Single knock‐out mutants of atipk2 α and atipk2 β were indistinguishable from the wild type, whereas the atipk2 α atipk2 β double mutant could not be obtained. Detailed genetic and cytological investigations showed that the mutation of At IPK 2 α and At IPK 2 β resulted in severely reduced transmission of male gametophyte as a result of abnormal pollen development and defective pollen tube guidance. In addition, the early embryo development of the atipk2 α atipk2 β double mutant was also aborted. Expressing either catalytically inactive or substrate specificity‐altered variants of At IPK 2β could not rescue the male gametophyte and embryogenesis defects of the atipk2 α atipk2 β double mutant, implying that the kinase activity of A t IPK 2 is required for pollen development, pollen tube guidance and embryogenesis. Taken together, our results provide genetic evidence for the requirement of inositol polyphosphate signaling in plant sexual reproduction.