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Long‐chain base phosphates modulate pollen tube growth via channel‐mediated influx of calcium
Author(s) -
Wu Juyou,
Qin Xiaoya,
Tao Shutian,
Jiang Xueting,
Liang YunKuan,
Zhang Shaoling
Publication year - 2014
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.12576
Subject(s) - pollen tube , microbiology and biotechnology , sphingosine 1 phosphate , biology , calcium , pollen , heterotrimeric g protein , extracellular , sphingosine kinase , biophysics , biochemistry , sphingosine , chemistry , signal transduction , botany , g protein , receptor , pollination , organic chemistry
Summary Long‐chain base phosphates ( LCBP s) have been correlated with amounts of crucial biological processes ranging from cell proliferation to apoptosis in animals. However, their functions in plants remain largely unknown. Here, we report that LCBP s, sphingosine‐1‐phosphate ( S 1 P ) and phytosphingosine‐1‐phosphate ( P hyto‐ S 1 P ), modulate pollen tube growth in a concentration‐dependent bi‐phasic manner. The pollen tube growth in the stylar transmitting tissue was promoted by SPHK 1 overexpression ( SPHK 1‐ OE ) but dampened by SPHK 1 knockdown ( SPHK 1‐ KD ) compared with wild‐type of A rabidopsis ; however, there was no detectable effect on in vitro pollen tube growth caused by misexpression of SPHK 1 . Interestingly, exogenous S 1 P or P hyto‐ S 1 P applications could increase the pollen tube growth rate in SPHK 1‐ OE , SPHK 1‐ KD and wild‐type of A rabidopsis. Calcium ion ( C a 2+ )‐imaging analysis showed that S 1 P triggered a remarkable increase in cytosolic C a 2+ concentration in pollen. Extracellular S 1 P induced hyperpolarization‐activated C a 2+ currents in the pollen plasma membrane, and the C a 2+ current activation was mediated by heterotrimeric G proteins. Moreover, the S 1 P ‐induced increase of cytosolic free C a 2+ inhibited the influx of potassium ions in pollen tubes. Our findings suggest that LCBP s functions in a signaling cascade that facilitates C a 2+ influx and modulates pollen tube growth.