Evolutionary origins of pectin methylesterase genes associated with novel aspects of angiosperm pollen tube walls

The ellipsoidal generative cell of the pollen grain of Endymion nonscriptus usually elongates further following germination and entry into the tube, producing attenuated extensions the forward one of which may reach into the vicinity of the vegetative nucleus. This shape change is accompanied by the stretching of the microtubule cytoskeleton of the cell, identified in the present work by immunofluorescence using monoclonal antibodies to tubulin. Complementary observations of living generative cells of Iris pseudacorus showed that they undergo slow undulatory movements accompanied by variation in shape and length during passage through the tube. Such changes must presumably be accompanied by modifications of the microtubule cytoskeleton. Colchicine at 1 mM eliminated microtubules from tubes and most generative cells of E. nonscriptus, but did not radically affect pollen-tube shape or extension growth, nor arrest the movements of the vegetative nucleus and generative cell into and through the tube. Generative cells in colchicinetreated pollen of Galanthus nivalis rounded up and failed to undergo the usual changes in shape during passage through the tube. Secondary consequences were changes in precedence in movement through the tube, and a greater dispersal along its length. On the assumption that no other cytoskeletal elements remain to be discovered, it seems likely that microfilaments rather than microtubules provide the motive force for movement in the tube, although the latter are involved in shaping the generative cell and adapting it to its passage.

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The putative pectin methylesterase gene, BcMF23a, is required for microspore development and pollen tube growth in Brassica campestris

Plant Cell Reports ◽

10.1007/s00299-018-2285-6 ◽

2018 ◽

Vol 37 (7) ◽

pp. 1003-1009 ◽

Cited By ~ 6

Author(s):

Xiaoyan Yue ◽

Sue Lin ◽

Youjian Yu ◽

Li Huang ◽

Jiashu Cao

Keyword(s):

Pollen Tube ◽

Pollen Tube Growth ◽

Brassica Campestris ◽

Pectin Methylesterase ◽

Tube Growth ◽

Microspore Development

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Microtubules and the positioning of the vegetative nucleus and generative cell in the angiosperm pollen tube: a quantitative study

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.1996.0190 ◽

1996 ◽

Vol 263 (1375) ◽

pp. 1299-1304 ◽

Cited By ~ 3

Keyword(s):

Pollen Tube ◽

Quantitative Study ◽

Generative Cell ◽

Vegetative Nucleus ◽

Angiosperm Pollen

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Actin Bundles in The Pollen Tube

International Journal of Molecular Sciences ◽

10.3390/ijms19123710 ◽

2018 ◽

Vol 19 (12) ◽

pp. 3710 ◽

Cited By ~ 3

Author(s):

Shujuan Zhang ◽

Chunbo Wang ◽

Min Xie ◽

Jinyu Liu ◽

Zhe Kong ◽

...

Keyword(s):

Pollen Tube ◽

Tip Growth ◽

Imaging Techniques ◽

Embryo Sac ◽

Pollen Tubes ◽

Growth Strategy ◽

Regulation Mechanism ◽

Actin Bundles ◽

Angiosperm Pollen ◽

Plant Pollen

The angiosperm pollen tube delivers two sperm cells into the embryo sac through a unique growth strategy, named tip growth, to accomplish fertilization. A great deal of experiments have demonstrated that actin bundles play a pivotal role in pollen tube tip growth. There are two distinct actin bundle populations in pollen tubes: the long, rather thick actin bundles in the shank and the short, highly dynamic bundles near the apex. With the development of imaging techniques over the last decade, great breakthroughs have been made in understanding the function of actin bundles in pollen tubes, especially short subapical actin bundles. Here, we tried to draw an overall picture of the architecture, functions and underlying regulation mechanism of actin bundles in plant pollen tubes.

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Myosin associated with the surfaces of organelles, vegetative nuclei and generative cells in angiosperm pollen grains and tubes

Journal of Cell Science ◽

10.1242/jcs.94.2.319 ◽

1989 ◽

Vol 94 (2) ◽

pp. 319-325

Author(s):

J. HESLOP-HARRISON ◽

Y. HESLOP-HARRISON

Keyword(s):

Pollen Tube ◽

Pollen Grains ◽

Giant Cells ◽

Pollen Tubes ◽

Microfilament Bundles ◽

Hyacinthus Orientalis ◽

Actin Fibrils ◽

Angiosperm Pollen ◽

Muscle Myosin ◽

Generative Cells

Myosin, detected by immunofluorescence using an antibody to bovine skeletal and smooth muscle myosin, has been localised on individual identifiable organelles from the grasses Alopecurus pratensis and Secale cereale, and on the surfaces of vegetative nuclei and generative cells from pollen and pollen tubes of Hyacinthus orientalis and Helleborus foetidus. Taken in conjunction with recent evidence showing that the growing pollen tube contains an actin cytoskeleton consisting of numerous mainly longitudinally oriented microfilament bundles, and that isolated pollen-tube organelles show ATP-dependent movement along the actin bundles of the giant cells of the characeous algae, this finding suggests that an actomyosin motility system is present in pollen tubes, and indicates that the movements of the different classes of inclusions are driven by interaction of the surface myosin with the actin fibrils at the zones of contact.

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