Cytoplasmic streaming velocity as a plant size determinant.
Cytoplasmic streaming is active transport widely occurring in plant cells ranging from algae to angiosperms. Although it has been revealed that cytoplasmic streaming is generated by organelle-associated myosin XI moving along actin bundles, the fundamental function in plants remains unclear. We generated high- and low-speed chimeric myosin XI by replacing the motor domains of Arabidopsis thaliana myosin XI-2 with those of Chara corallina myosin XI and Homo sapiens myosin Vb, respectively. Surprisingly, the plant sizes of the transgenic Arabidopsis expressing high- and low-speed chimeric myosin XI-2 were larger and smaller, respectively, than that of the wild-type plant. This size change correlated with acceleration and deceleration, respectively, of cytoplasmic streaming. Our results strongly suggest that cytoplasmic streaming is a key determinant of plant size. Furthermore, because cytoplasmic streaming is a common system for intracellular transport in plants, our system could have applications in artificial size control in plants.
Live Cell Molecular Imaging Research Team, RIKEN Center for Advanced Photonics, Wako, Saitama 351-0198, Japan; Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan. Electronic address: tominaga@riken.jp.
Motoki
M
Tominaga
Atsushi
A
Kimura
Etsuo
E
Yokota
Takeshi
T
Haraguchi
Teruo
T
Shimmen
Keiichi
K
Yamamoto
Akihiko
A
Nakano
Kohji
K
Ito
D000199:Actins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000254:growth & development* / Q000378:metabolism*; D048429:Cell Size; D003595:Cytoplasmic Streaming / Q000502:physiology*; D015151:Immunoblotting; D009218:Myosins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011523:Protoplasts / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000199:Actins; D012333:RNA, Messenger; D009218:Myosins