Advertisement

Sexual Plant Reproduction

, Volume 19, Issue 2, pp 83–91 | Cite as

Rop1Ps promote actin cytoskeleton dynamics and control the tip growth of lily pollen tube

  • Heping Zhao
  • Haiyun RenEmail author
Original Article

Abstract

Rop, the small GTPase of the Rho family in plants, is believed to exert molecular control over dynamic changes in the actin cytoskeleton that affect pollen tube elongation characteristics. In the present study, microinjection of Rop1Ps was used to investigate its effects on tip growth and evidence of interaction with the actin cytoskeleton in lily pollen tubes. Microinjected wild type WT-Rop1Ps accelerated pollen tube elongation and induced actin bundles to form in the very tip region. In contrast, microinjected dominant negative DN-rop1Ps had no apparent effect on pollen tube growth or microfilament organization, whereas microinjection of constitutively active CA-rop1Ps induced depolarized growth and abnormal pollen tubes in which long actin bundles in the shank of the tube were distorted. Injection of phalloidin, a potent F-actin stabilizer that inhibits dynamic changes in the actin cytoskeleton, prevented abnormal growth of the tubes and suppressed formation of distorted actin bundles. These results indicate that Rop1Ps exert control over important aspects of tip morphology involving dynamics of the actin cytoskeleton that affect pollen tube elongation.

Keywords

Small GTPase Rop Microinjection Pollen tube growth Actin cytoskeleton 

Notes

Acknowledgements

We thank Prof. Dr. Zhenbiao Yang (University of California, Riverside, USA) for kindly providing all constructs and for his comments on the manuscript. We thank Dr. Ming Yuan (China Agricultural University) for critical reading and comments on the manuscript. This work was supported by the National Natural Science Foundation for Distinguished Young Scholars (Grant No. 30325005), the National Natural Science Foundation of China (Grant No. 30270087), the National Basic Research Program of China (Grant No. 2006CB100100) and the Key Laboratory Research Foundation of State Education Ministry of China for Visiting Scholars.

Supplementary material

Supplementary material 1

Supplementary material 2

Supplementary material 3

Supplementary material 4

Supplementary material 5

Supplementary material 6

References

  1. Ausubel F, Brent R, Kingston RE, Moore DD, Seidman JG, Smith JA, Struhl K (1998) In: Yan ZY, Wang HL (eds) Short protocols in molecular biology. 3rd edn. Science Press, Beijing, pp 649–652(Chinese, translated)Google Scholar
  2. Battey NH, James NC, Greenland AJ, Brownlee C (1999) Exocytosis and endocytosis. Plant Cell 11:643–660CrossRefPubMedGoogle Scholar
  3. Bourne HR, Sanders DA, McCormick F (1991) The GTPase superfamily: conserved structure and molecular mechanism. Nature 349:117–127CrossRefPubMedGoogle Scholar
  4. Cleary AL, Gunning BES, Wasteneys GO, Hepler PK (1992) Microtubule and F-actin dynamics at the division site in living Tradescantia stamen hair cells. J Cell Sci 103:977–988Google Scholar
  5. Franklin-Tong VE (1999) Signaling and the modulation of pollen tube growth. Plant Cell 11:727–738CrossRefPubMedGoogle Scholar
  6. Fu Y, Wu G, Yang Z (2001) Rop GTPase-dependent dynamics of tip-localized F-actin controls tip growth in pollen tubes. J Cell Biol 152:1019–1032CrossRefPubMedGoogle Scholar
  7. Gibbon BC, Kovar DR, Staiger CJ (1999) Latrunculin B has different effects on pollen germination and tube growth. Plant Cell 11:2349–2363CrossRefPubMedGoogle Scholar
  8. Hall A (1998) Rho GTPases and the actin cytoskeleton. Science 279:509–514CrossRefPubMedGoogle Scholar
  9. Kost B, Lemichez E, Spielhofer P, Hong Y, Tolias K, Carpenter C, Chua N-H (1999) Rac homologues and compartmentalized phosphatidylinositol 4,5-bisphosphate act in a common pathway to regulate polar pollen tube growth. J Cell Biol 145:317–330CrossRefPubMedGoogle Scholar
  10. Kost B, Spielhofer P, Chua NH (1998) A GFP-mouse talin fusion protein labels plant actin filaments in vivo and visualizes the actin cytoskeleton in growing pollen tubes. Plant J 16:393–401CrossRefPubMedGoogle Scholar
  11. Li H, Lin Y, Heath RM, Zhu MX, Yang Z (1999) Control of pollen tube tip growth by a Rop GTPase-dependent pathway that leads to tip-localized calcium influx. Plant Cell 11:1731–1742CrossRefPubMedGoogle Scholar
  12. Li H, Wu G, Ware D, Davis KR, Yang Z (1998a) Arabidopsis Rho-related GTPases: differential gene expression in pollen and polar localization in fission yeast. Plant Physiol 118:407–417CrossRefGoogle Scholar
  13. Li Y, Yan L-F, Yen LF, Xu S-X, Zee SY (1998b) Distribution of F-actin and microtubules in pollen and pollen tube of Lilium davidii. Acta Bot Sin 40:890–894Google Scholar
  14. Li Y, Zee SY, Liu YM, Huang BQ, Yen LF (2001) Circular F-actin bundles and a G-actin gradient in pollen and pollen tubes of Lilium davidii. Planta 213:722–730CrossRefPubMedGoogle Scholar
  15. Lovy-Wheeler A, Wilsen KL, Baskin TI, Hepler PK (2005) Enhanced fixation reveals the apical cortical fringe of actin filaments as a consistent feature of the pollen tube. Planta 221:95–104CrossRefPubMedGoogle Scholar
  16. Miller DD, Lancelle SA, Hepler PK (1996) Actin microfilaments do not form a dense meshwork in Lilium longiflorum pollen tube tips. Protoplasma 195:123–132CrossRefGoogle Scholar
  17. Pierson ES, Miller DD, Callaham DA, Shipley AM, Rivers BA, Cresti M, Hepler PK (1994) Pollen tube growth is coupled to the extracellular calcium ion flux and the intracellular calcium gradient: effect of BAPTA-type buffers and hypertonic media. Plant Cell 6:1815–1828CrossRefPubMedGoogle Scholar
  18. Pierson ES (1988) Rhodamine-phalloidin staining of F-actin in pollen after dimethyl sulphoxide permeabilisation: a comparison with the conventional formaldehyde preparation. Sex Plant Reprod 1:83–87CrossRefGoogle Scholar
  19. Staiger CJ, Yuan M, Valenta R, Shaw PJ, Warn RM, Lloyd CW (1994) Microinjected profilin affects cytoplasmic streaming in plant cells by rapidly depolymerizing actin microfilaments. Curr Biol 4:215–219CrossRefPubMedGoogle Scholar
  20. Taylor LP, Hepler PK (1997) Pollen germination and tube growth. Annu Rev Plant Physiol Plant Mol Biol 48:461–491CrossRefPubMedGoogle Scholar
  21. Van GK, Köhler RH, Verbelen JP (2002) Plant mitochondria move on F-actin, but their positioning in the cortical cytoplasm depends on both F-actin and microtubules. J Exp Bot 53:659–667CrossRefGoogle Scholar
  22. Vidali L, Hepler PK (2000) Actin in pollen and pollen tubes. In: Staiger CJ, Baluska F, Volkmann D, Barlow PW (eds) Actin: a dynamic framework for multiple plant cell functions. Kluwer Academic Press, Dordrecht, Netherlands, pp 323–345Google Scholar
  23. Vidali L, McKenna ST, Hepler PK (2001) Actin polymerization is essential for pollen tube growth. Mol Biol Cell 12:2534–2545PubMedGoogle Scholar
  24. Yang Z, Watson JC (1993) Molecular cloning and characterization of rho, a ras-related small GTP-binding protein from the garden pea. Proc Natl Acad Sci USA 90:8732–8736PubMedCrossRefGoogle Scholar
  25. Zhao H-P, Liu A-X, Ren D-T, Liu G-Q, Yen L-F (1999) Identification of myosin on the surface of wheat mitochondria. Acta Bot Sin 41:1303–1306Google Scholar
  26. Zheng ZL, Yang Z (2000) The Rop GTPase: an emerging signalling switch in plants. Plant Mol Biol 44:1–9CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of EducationBeijing Normal UniversityBeijingPRChina

Personalised recommendations