Polar protein transport between apical and basal cells during tobacco early embryogenesis

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Key message

We found that protein trafficking between apical and basal cell can be unidirectional, which reveals the different roles of the two cells in the cell-to-cell communication between them during early embryogenesis.


In most angiosperm species, asymmetric zygote division results in an apical cell and a basal cell that have distinct cell fates. Much has been speculated about possible communication between these cell types in relation to their cell fate determination. Here, we report on the use of photoactivatable green fluorescent protein (PA-GFP) in tobacco to trace intercellular communication between apical and basal cells during early embryogenesis. We found that PA-GFP was transported between apical and basal cells of a two-celled proembryo, and that protein trafficking was unidirectional toward the apical cell, highlighting different cell communication roles. Further ultrastructural analysis showed numerous plasmodesmata in the walls connecting the apical and basal cells, which may provide channels for protein trafficking. Our data show a possible unique method of cell-to-cell communication between apical and basal cells during early embryogenesis.

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Confocal laser scanning microscope


Complementary deoxyribonucleic acid


Green fluorescent protein


Mitogen-activated protein kinase kinase kinase




Non-cell autonomous proteins


Open-reading frame


Photoactivatable green fluorescent protein






Root apical meristem


Ribonucleic acid


Soluble green fluorescent protein


Target of MONOPTEROS 7






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The project was supported by the “973” Program (2013CB126900), National Natural Science Fund of China (31170297; 31070284). We warmly thank Prof. Oparka from University of Edinburgh for his generous gift of T-Easy Vector containing PA-GFP.

Author information

Correspondence to Meng-xiang Sun.

Additional information

Communicated by M. Otegui.

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Li, S., He, Y., Zhao, J. et al. Polar protein transport between apical and basal cells during tobacco early embryogenesis. Plant Cell Rep 32, 285–291 (2013).

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  • Photoactivatable green fluorescent protein (PA-GFP)
  • Cell-to-cell communication
  • Plasmodesmata
  • Apical cell
  • Basal cell
  • Protein trafficking