Yeungnam Univ J Med.  1985 Dec;2(1):175-181. 10.12701/yujm.1985.2.1.175.

Cytological Study of the Introduction of Agrobacterium tumefaciens Spheroplasts into Nicotiana tabacum Protoplasts

• Kim JH
• Koo YB
• Lee KY

• KMID: 2373024
• DOI: http://doi.org/10.12701/yujm.1985.2.1.175

Abstract

Agrobacterium tumefaciens induces cancerous growths called crown galls at wound sites on dicotyledonous plants. A large plasmid called T1 plasmid is responsible for virulence. Upon tumor induction, part of the plasmid, termed T-DNA, becomes integrated into plant genome and its genetic sequences are expressed. These properties allow T1 plasmids to be used as gene vectors in plants. Several in vitro methods for the transfer of T1 plasmid into plant cell have been developed. One of them is the treatment of bacterial spheroplasts and plant protoplasts mixture with polyethylene glycol that is generally used as fusogen in cell-to-cell fusion. Several workers investigated the interaction of bacterial spheroplasts with plant protoplasts in the presence of polyethylene glycol and suggested that the interaction is not fusion but endocytosis. In this report we observed the interaction of Agrobacterium tumefaciens spheroplasts with Nicotiana tabacum protoplasts by electron microscope. Agrobacterium tumefaciens spheroplasts with Nicotiana tabacum protoplasts were prepared and mixed in the presence of polyethylene glycol and high pH-high Ca²âº buffer. Then the interaction of the spheroplasts with the protoplasts was examined by transmission electron microscope. After the treatment of polyethylene glycol the spheroplasts adhered to the surface of the protoplasts and then they were engulfed by the protoplasts. After the high pH-high Ca²âº buffer treatment the engulfed spheroplasts lost their cell integrity. No fusion process was observed. Thus all these observation suggest that the introduction process of Agrobacterium tumefaciens spheroplasts into Nicotiana tabacum protoplasts with the aid of polyethylene glycol is endocytosis.

MeSH Terms

Agrobacterium tumefaciens*
Agrobacterium*
Endocytosis
Genome, Plant
In Vitro Techniques
Plant Cells
Plant Tumors
Plants
Plasmids
Polyethylene Glycols
Protoplasts*
Spheroplasts*
Tobacco*
Virulence
Wounds and Injuries
Polyethylene Glycols