Microinjection of Guanine NucleotideAnalogues into Lily Pollen Tubes Results in Isodiametric TipExpansion

Abstract

Heterotrimeric and small G-proteins aresupposed to participate in tip growth of plant cells. Quantitative changes intip growth rate after introduction of non-hydrolysable guanine nucleotideanalogues (NA) into lily pollen tubes have been interpreted as support for thehypothesis that heterotrimeric G-proteins regulate tube elongation (Ma et al.,1999[11]). Here, we report that microinjection of guanineNA into lily pollen tubes causes loss of growth polarity, resulting inisodiametric tip swelling. Our results are compatible with current modelssuggesting an involvement of plant Rho-related small G-proteins (Rop) in themaintenance of pollen tube polarity and in tip morphogenesis.

Abbreviations

ADP-β-S: adenosine5′-O-(2-thiodiphosphate)

ATP-γ-S: adenosine5′-O-(3-thiotriphosphate)

GDP-β-S: guanosine5′-O-(2-thiodiphosphate)

GTP-γ-S: guanosine5′-O-(3-thiotriphosphate)

NA: nucleotideanalogues

Tip growth - Liliumlongiflorum - microinjection - pollentube - G-proteins - cell polarity

References

• 01 Assmann, S. M.. (1996);  Guard cellG proteins.  Trends PlantSci.. 1 73-74
• 02 Benkert, R.,, Obermeyer,  G.,, andBentrup, F. W.. (1997);  The turgorpressure of growing lily pollentubes.  Protoplasma. 198 1-8
• 03 Bischoff, F.,, Molendijk, A.,, Rajendrakumar,  C.,, andPalme,  K.. (1999);  GTP-bindingproteins in plants.  Cell. Mol. LifeSci.. 55 233-256
• 04 Cvrčková, F.,, Eliáš,  M.,, Hála, M.,, Obermeyer,  G.,, andžársky V.. (2001) SmallGTPases and conserved signalling pathways in plant cell morphogenesis: fromexocytosis to the Exocyst. Cell Biology of Plant and Fungal TipGrowth. Geitmann, A. et al., eds. Amsterdam; IOSPress pp.105-122
• 05 Engel,  E.,, Richter, K.,, Obermeyer,  G.,, Briza, P.,, Kungl, A. J.,, Simon, B.,, Auer,  M.,, Ebner, C.,, Rheinberger, H.-J.,, Breitenbach,  M.,, andFerreira, F.. (1997);  Immunological andbiological properties of Bet v4, a novel birch pollen allergen with two EF-handcalcium binding domains.  J. Biol.Chem.. 272 28630-28637
• 06 Franklin-Tong, V. E.,, Drobag, B.,, Allan, A. C.,, Watkins,  P. A.C.,, and Trewavas, A. J.. (1996);  Growth ofpollen tubes of Papaver rhoeas is regulated by aslow-moving calcium wave propagated by inositol1,4,5-triphosphate.  PlantCell. 8 1305-1321
• 07 Freeman, G. H., and Halton, J. H.. (1951);  Note on anexact treatment of contingency, goodness of fit and other problems ofsignificance.  Biometrika. 38 141-149
• 08 Fu,  Y.,, Wu, G.,, and Yang, Z.. (2001);  Rop GTPase-dependentdynamics of tip-localized F-actin controls tip growth in pollentubes.  J. CellBiol.. 152 1019-1032
• 09 Kost,  B.,, Lemichez, E.,, Spielhofer,  P.,, Hong, Y.,, Tolias,  K.,, and Chua, N. H.. (1999);  Rachomologues and compartmentalized phosphatidylinositol 4,5-bisphosphate act in acommon pathway to regulate polar pollen tube growth.  J. CellBiol.. 145 317-330
• 10 Li,  H.,, Lin, Y.,, Heath, R. M.,, Zhu, M. X.,, and Yang, Z.. (1999);  Control of pollen tubetip growth by a Rop GTPase-dependent pathway that leads to tip-localized calciuminflux.  PlantCell. 11 1731-1742
• 11 Ma,  L.,, Xu, X.,, Cui,  S.,, and Sun, D.. (1999);  The presence of aheterotrimeric G protein and its role in signal transduction of extracellularcalmodulin in pollen germination and tube growth.  PlantCell. 11 1351-1363
• 12 Obermeyer,  G.,, Nagl, W.,, Nagl,  M.,, Höftberger, M.,, and Bentrup, F. W.. (1998);  In-vitrogermination and growth of lily pollen tubes is affected by protein phosphataseinhibitors.  Planta. 207 303-312
• 13 Valster, A. H.,, Hepler, P. K.,, and Chernoff, J.. (2000);  Plant GTPases: theRhos in bloom.  Trends CellBiol.. 10 141-146
• 14 Zheng, Z. L., and Yang, Z.. (2000);  The Rop GTPase switchturns on polar growth in pollen.  Trends PlantSci.. 5 298-303
• 15 Ziman,  M.,, O'Brien, J. M.,, Ouelette, L. A.,, Church, W. R.,, and Johnson, D. I.. (1991);  Mutationalanalysis of Cdc42Sc, a Saccharomyces cerevisiae genethat encodes a putative GTP/binding protein involved in the control of cellpolarity.  Mol. CellBiol.. 11 3537-3544

Section Editor: A. M. C. Emons