Limits...
Myosin-Powered Membrane Compartment Drives Cytoplasmic Streaming, Cell Expansion and Plant Development.

Peremyslov VV, Cole RA, Fowler JE, Dolja VV - PLoS ONE (2015)

Bottom Line: Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics.Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming.It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, United States of America.

ABSTRACT
Using genetic approaches, particle image velocimetry and an inert tracer of cytoplasmic streaming, we have made a mechanistic connection between the motor proteins (myosins XI), cargo transported by these motors (distinct endomembrane compartment defined by membrane-anchored MyoB receptors) and the process of cytoplasmic streaming in plant cells. It is shown that the MyoB compartment in Nicotiana benthamiana is highly dynamic moving with the mean velocity of ~3 μm/sec. In contrast, Golgi, mitochondria, peroxisomes, carrier vesicles and a cytosol flow tracer share distinct velocity profile with mean velocities of 0.6-1.5 μm/sec. Dominant negative inhibition of the myosins XI or MyoB receptors using overexpression of the N. benthamiana myosin cargo-binding domain or MyoB myosin-binding domain, respectively, resulted in velocity reduction for not only the MyoB compartment, but also each of the tested organelles, vesicles and cytoplasmic streaming. Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics. Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming. It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering. These results support a model according to which myosin-dependent, MyoB receptor-mediated transport of a specialized membrane compartment that is conserved in all land plants drives cytoplasmic streaming that carries organelles and vesicles and facilitates cell growth and plant development.

No MeSH data available.


Related in: MedlinePlus

Representative images of the synthetic quintuple mutant Arabidopsis plants xi-k xi-1 myob1-3 and xi-k xi-2 myob1-3 compared to Columbia and parental lines myob1-3, xi-k xi-1 and xi-k xi-2 at 7 weeks after sawing.(A) The stems with siliques and flowers; note irregular stem shape in quintuple mutant plants. (B) Fragments of the stems with siliques; note irregular orientation of siliques relative to stems and misshaped silique stalks. (C) Leaf rosettes (stems and roots were cut off).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4591342&req=5

pone.0139331.g005: Representative images of the synthetic quintuple mutant Arabidopsis plants xi-k xi-1 myob1-3 and xi-k xi-2 myob1-3 compared to Columbia and parental lines myob1-3, xi-k xi-1 and xi-k xi-2 at 7 weeks after sawing.(A) The stems with siliques and flowers; note irregular stem shape in quintuple mutant plants. (B) Fragments of the stems with siliques; note irregular orientation of siliques relative to stems and misshaped silique stalks. (C) Leaf rosettes (stems and roots were cut off).

Mentions: Interestingly, stem morphology was also affected in both s5KOs, but not in corresponding controls. As shown in Fig 5A, unlike control lines that exhibited relatively straight stems, the stems of both s5KO mutants were often bent and/or appeared wavy. Analogous morphological abnormalities were seen in the stalks connecting siliques to the stems. Whereas these stalks were straight and pointing slightly upward in four control lines, they were bent and pointing sharply upward or downward in both s5KOs (Fig 5B). In contrast, the overall rosette shape and leaf morphology in the s5KO mutants appeared normal despite the reduced rosette span (Fig 5C).


Myosin-Powered Membrane Compartment Drives Cytoplasmic Streaming, Cell Expansion and Plant Development.

Peremyslov VV, Cole RA, Fowler JE, Dolja VV - PLoS ONE (2015)

Representative images of the synthetic quintuple mutant Arabidopsis plants xi-k xi-1 myob1-3 and xi-k xi-2 myob1-3 compared to Columbia and parental lines myob1-3, xi-k xi-1 and xi-k xi-2 at 7 weeks after sawing.(A) The stems with siliques and flowers; note irregular stem shape in quintuple mutant plants. (B) Fragments of the stems with siliques; note irregular orientation of siliques relative to stems and misshaped silique stalks. (C) Leaf rosettes (stems and roots were cut off).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591342&req=5

pone.0139331.g005: Representative images of the synthetic quintuple mutant Arabidopsis plants xi-k xi-1 myob1-3 and xi-k xi-2 myob1-3 compared to Columbia and parental lines myob1-3, xi-k xi-1 and xi-k xi-2 at 7 weeks after sawing.(A) The stems with siliques and flowers; note irregular stem shape in quintuple mutant plants. (B) Fragments of the stems with siliques; note irregular orientation of siliques relative to stems and misshaped silique stalks. (C) Leaf rosettes (stems and roots were cut off).
Mentions: Interestingly, stem morphology was also affected in both s5KOs, but not in corresponding controls. As shown in Fig 5A, unlike control lines that exhibited relatively straight stems, the stems of both s5KO mutants were often bent and/or appeared wavy. Analogous morphological abnormalities were seen in the stalks connecting siliques to the stems. Whereas these stalks were straight and pointing slightly upward in four control lines, they were bent and pointing sharply upward or downward in both s5KOs (Fig 5B). In contrast, the overall rosette shape and leaf morphology in the s5KO mutants appeared normal despite the reduced rosette span (Fig 5C).

Bottom Line: Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics.Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming.It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, United States of America.

ABSTRACT
Using genetic approaches, particle image velocimetry and an inert tracer of cytoplasmic streaming, we have made a mechanistic connection between the motor proteins (myosins XI), cargo transported by these motors (distinct endomembrane compartment defined by membrane-anchored MyoB receptors) and the process of cytoplasmic streaming in plant cells. It is shown that the MyoB compartment in Nicotiana benthamiana is highly dynamic moving with the mean velocity of ~3 μm/sec. In contrast, Golgi, mitochondria, peroxisomes, carrier vesicles and a cytosol flow tracer share distinct velocity profile with mean velocities of 0.6-1.5 μm/sec. Dominant negative inhibition of the myosins XI or MyoB receptors using overexpression of the N. benthamiana myosin cargo-binding domain or MyoB myosin-binding domain, respectively, resulted in velocity reduction for not only the MyoB compartment, but also each of the tested organelles, vesicles and cytoplasmic streaming. Furthermore, the extents of this reduction were similar for each of these compartments suggesting that MyoB compartment plays primary role in cytosol dynamics. Using gene knockout analysis in Arabidopsis thaliana, it is demonstrated that inactivation of MyoB1-4 results in reduced velocity of mitochondria implying slower cytoplasmic streaming. It is also shown that myosins XI and MyoB receptors genetically interact to contribute to cell expansion, plant growth, morphogenesis and proper onset of flowering. These results support a model according to which myosin-dependent, MyoB receptor-mediated transport of a specialized membrane compartment that is conserved in all land plants drives cytoplasmic streaming that carries organelles and vesicles and facilitates cell growth and plant development.

No MeSH data available.


Related in: MedlinePlus