A tip-high, Ca(2+) -interdependent, reactive oxygen species gradient is associated with polarized growth in Fucus serratus zygotes.
We report the existence of a tip-high reactive oxygen species (ROS) gradient in growing Fucus serratus zygotes, using both 5-(and 6-) chloromethyl-2',7'-dichlorodihydrofluorescein and nitroblue tetrazolium staining to report ROS generation. Suppression of the ROS gradient inhibits polarized zygotic growth; conversely, exogenous ROS generation can redirect zygotic polarization following inhibition of endogenous ROS. Confocal imaging of fluo-4 dextran distributions suggests that the ROS gradient is interdependent on the tip-high [Ca(2+)](cyt) gradient which is known to be associated with polarized growth. Our data support a model in which localized production of ROS at the rhizoid tip stimulates formation of a localized tip-high [Ca(2+)](cyt) gradient. Such modulation of intracellular [Ca(2+)](cyt) signals by ROS is a common motif in many plant and algal systems and this study extends this mechanism to embryogenesis.
Coelho
Susana M B
SM
UMR7139, Station Biologique, Centre National de la Recherche Scientifique, Université Pierre & Marie Curie Paris VI, Place Georges Teissier, Roscoff Cedex, France.
Brownlee
Colin
C
Bothwell
John H F
JH
D002118:Calcium / Q000378:metabolism*; D044645:Fucus / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D018613:Microscopy, Confocal; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012098:Reproduction; D010738:Type C Phospholipases / Q000378:metabolism
D017382:Reactive Oxygen Species; D010738:Type C Phospholipases; D002118:Calcium