Pollen vegetative cell-specific expression of Bra r 1: Useful tool for observation of the vegetative nucleus and identification of transgenic pollen by nuclear-targeted GFP

Takashi Okada, K. Toriyama

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Bra r 1 encodes a novel Ca2+-binding protein specifically expressed in pollen and is localized in cytoplasm of pollen and pollen tubes. In this study, we demonstrated the expression of green fluorescent protein (GFP) with a nuclear localization signal under the control of Bra r 1 promoter in tobacco pollen. A fluorescent signal was detected in the vegetative nucleus (VN) but not in generative and sperm cell nuclei, indicating pollen vegetative cell-specific expression of Bra r 1. The fluorescent signal in elongating pollen tubes was stronger than that in mature pollen, indicating that the expression of Bra r 1 was more activated during pollen tube growth. This result suggests that Bra r 1 protein might be necessary for pollen tube growth. The pattern of green fluorescence in the VN revealed that VN chromatin is dispersed during the mid-bicellular pollen stage and condensed at the mature stage. This suggests that the level of chromatin condensation might be linked with gene expression in pollen vegetative cells. We also found that the expression of GFP and its targeting of the VN have no detrimental effect on pollen maturation and pollen tube growth. Expression of GFP in pollen thus makes rapid non-destructive monitoring of transgenic pollen and pollen tubes possible. The GFP which moved into the VN was found to be a convenient tool for observation of the VN and could be useful as a selectable marker of transgenic pollen for the analysis of pollen-specific genes.

Original languageEnglish
Pages (from-to)301-307
Number of pages7
JournalSexual Plant Reproduction
Volume13
Issue number6
DOIs
Publication statusPublished - 2001 Jul

Keywords

  • Bra r 1
  • Ca-binding protein
  • GFP
  • Pollen tube growth
  • Vegetative nucleus

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

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