Found MOV) at: doi:10.1371/journal.pone.0005744.s002 (3.35 MB Movie S2 Time lapse LSCM of Nicotiana tobaccum pollen tube transformed with Lifeact-mEGFP. One frame was acquired every five seconds. Total elapsed time was 245 seconds. Scale bar is 10 mm. Found at: doi:10.1371/journal.pone.0005744.s003 (1.96 MB MOV) Movie S3 Time lapse LSCM of Lilium formosanum pollen tube transformed with Lifeact-mEGFP. One frame was acquired every three seconds. Total elapsed time was 96 seconds. Scale bar is 10 mm. Found at: doi:10.1371/journal.pone.0005744.s004 (1.60 MB MOV) Movie S4 Time lapse spinning disc confocal images of Lifeact- mEGFP expressing Moss caulonemal cell. One frame was acquired every two seconds. Total elapsed time was 120 seconds. Found at: doi:10.1371/journal.pone.0005744.s005 (0.55 MB MOV) Movie S5 Time lapse LSCM DIC images of Lilium formosa- num pollen tube transformed with Lifeact-mEGFP and treated with 2 nm Latrunculin B. One frame was acquired every three seconds. Total elapsed time was 246 seconds. Scale bar is 10 mm. References 1. Menand B, Calder G, Dolan L (2007) Both chloronemal and caulonemal cells expand by tip growth in the moss Physcomitrella patens. J Exp Bot 58: 1843–1849. doi:10.1093/jxb/erm047. 2. Vidali L, McKenna ST, Hepler PK (2001) Actin polymerization is essential for pollen tube growth. Mol Biol Cell 12: 2534–2545. 3. Harries PA, Pan A, Quatrano RS (2005) Actin-related protein2/3 complex component ARPC1 is required for proper cell morphogenesis and polarized cell growth in Physcomitrella patens. Plant Cell 17: 2327–2339. doi:10.1105/ tpc.105.033266. 4. Finka A, Schaefer DG, Saidi Y, Goloubinoff P, Zry¨d J (2007) In vivo visualization of F-actin structures during the development of the moss Physcomitrella patens. New Phytol 174: 63–76. doi:10.1111/j.1469- 8137.2007.01989.x. 5. Chen CY, Wong EI, Vidali L, Estavillo A, Hepler PK, et al. 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Meske V, Hartmann E (1995) Reorganization of microfilaments in protonemal tip cells of the moss Ceratodon purpureus during the phototropic response. Protoplasma 188: 59–69. 15. Walker LM, Sack FD (1995) Microfilament distribution in protonemata of the moss Ceratodon. Protoplasma 189: 229–237. Lifeact-mEGFP in Plant Cells Found at: doi:10.1371/journal.pone.0005744.s006 (15.17 MOV) MB Movie S6 Time lapse LSCM fluorescence images of Lilium formosanum pollen tube transformed with Lifeact-mEGFP and treated with 2 nm Latrunculin B. One frame was acquired every three seconds. Total elapsed time was 246 seconds. Scale bar is 10 mm. Found at: doi:10.1371/journal.pone.0005744.s007 (15.17 MB MOV) Acknowledgments We thank Dr. Wedlich-Soldner for the sequence of the Lifeact peptide, and Dr. W. Lee for Yeast genomic DNA. We also thank Dr. Alice Cheung for the pollen expression plasmids. We thank Dr. Elsbeth Walker for the use of her biolistic equipment. 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Hwang J, Gu Y, Lee Y, Yang Z (2005) Oscillatory ROP GTPase activation leads the oscillatory polarized growth of pollen tubes. Mol Biol Cell 16: 5385–5399. doi:10.1091/mbc.E05-05-0409. 29. Finka A, Saidi Y, Goloubinoff P, Neuhaus J, Zry¨d J, et al. (2008) The knock-out of ARP3a gene affects F-actin cytoskeleton organization altering cellular tip growth, morphology and development in moss Physcomitrella patens. Cell Motil Cytoskel 65: 769–784. doi:10.1002/cm.20298. 30. Ketelaar T, Anthony RG, Hussey PJ (2004) Green fluorescent protein-mTalin causes defects in actin organization and cell expansion in Arabidopsis and inhibits actin depolymerizing factor’s actin depolymerizing activity in vitro. Plant Physiol 136: 3990–3998. doi:10.1104/pp.104.050799. PLoS ONE | www.plosone.org 14 May 2009 | Volume 4 | Issue 5 | e5744