Regular Paper

Journal of Plant Research

, Volume 126, Issue 3, pp 387-394

Open Access This content is freely available online to anyone, anywhere at any time.

Analysis of gamete membrane dynamics during double fertilization of Arabidopsis

  • Tomoko IgawaAffiliated withThe Plant Science Education Unit, The Graduate School of Biological Sciences, Nara Institute of Science and TechnologyInitiative Research Program, RIKEN Advanced Science InstituteGraduate School of Horticulture, Chiba University Email author 
  • , Yuki YanagawaAffiliated withThe Plant Science Education Unit, The Graduate School of Biological Sciences, Nara Institute of Science and TechnologyPlant Functional Genomics Research Group, RIKEN Plant Science Center Email author 
  • , Shin-ya MiyagishimaAffiliated withInitiative Research Program, RIKEN Advanced Science InstituteCenter for Frontier Research, National Institute of Genetics
  • , Toshiyuki MoriAffiliated withInitiative Research Program, RIKEN Advanced Science InstituteWaseda Institute for Advanced Study, Waseda University

Abstract

Angiosperms have a unique sexual reproduction system called “double fertilization.” One sperm cell fertilizes the egg and another sperm cell fertilizes the central cell. To date, plant gamete membrane dynamics during fertilization has been poorly understood. To analyze this unrevealed gamete subcellular behavior, live cell imaging analyses of Arabidopsis double fertilization were performed. We produced female gamete membrane marker lines in which fluorescent proteins conjugated with PIP2a finely visualized egg cell and central cell surfaces. Using those lines together with a sperm cell membrane marker line expressing GCS1-GFP, the double fertilization process was observed. As a result, after gamete fusion, putative sperm plasma membrane GFP signals were occasionally detected on the egg cell surface adjacent to the central cell. In addition, time-lapse imaging revealed that GCS1-GFP signals entered both the egg cell and the central cell in parallel with the sperm cell movement toward the female gametes during double fertilization. These findings suggested that the gamete fusion process based on membrane dynamics was composed of (1) plasma membrane fusion on male and female gamete surfaces, (2) entry of sperm internal membrane components into the female gametes, and (3) plasmogamy.

Keywords

Arabidopsis Double fertilization GCS1 Membrane dynamics Plasma membrane intrinsic protein 2A (PIP2a)