The reorganization of actin filaments is required for vacuolar fusion of guard cells during stomatal opening in Arabidopsis.
The reorganization of actin filaments (AFs) and vacuoles in guard cells is involved in the regulation of stomatal movement. However, it remains unclear whether there is any interaction between the reorganization of AFs and vacuolar changes during stomatal movement. Here, we report the relationship between the reorganization of AFs and vacuolar fusion revealed in pharmacological experiments, and characterizing stomatal opening in actin-related protein 2 (arp2) and arp3 mutants. Our results show that cytochalasin-D-induced depolymerization or phalloidin-induced stabilization of AFs leads to an increase in small unfused vacuoles during stomatal opening in wild-type (WT) Arabidopsis plants. Light-induced stomatal opening is retarded and vacuolar fusion in guard cells is impaired in the mutants, in which the reorganization and the dynamic parameters of AFs are aberrant compared with those of the WT. In WT, AFs tightly surround the small separated vacuoles, forming a ring that encircles the boundary membranes of vacuoles partly fused during stomatal opening. In contrast, in the mutants, most AFs and actin patches accumulate abnormally around the nuclei of the guard cells, which probably further impair vacuolar fusion and retard stomatal opening. Our results suggest that the reorganization of AFs regulates vacuolar fusion in guard cells during stomatal opening.
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
Li-Juan
LJ
Li
Fei
F
Ren
Xin-Qi
XQ
Gao
Peng-Cheng
PC
Wei
Xue-Chen
XC
Wang
D008841:Actin Cytoskeleton / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D051377:Actin-Related Protein 2 / Q000235:genetics; D051378:Actin-Related Protein 3 / Q000235:genetics; D000199:Actins / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics; D015638:Cytochalasin D / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008027:Light; D008561:Membrane Fusion / Q000187:drug effects / Q000528:radiation effects; D009154:Mutation / Q000235:genetics; D010590:Phalloidine / Q000494:pharmacology; D054046:Plant Stomata / Q000166:cytology* / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D058105:Polymerization / Q000187:drug effects / Q000528:radiation effects; D059008:Time-Lapse Imaging; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects
C512742:ARP2 protein, Arabidopsis; D051377:Actin-Related Protein 2; D051378:Actin-Related Protein 3; D000199:Actins; D029681:Arabidopsis Proteins; C478027:DIS1 protein, Arabidopsis; D049452:Green Fluorescent Proteins; D010590:Phalloidine; D015638:Cytochalasin D