Protoplast Fusion

   

(Image: F. Liu et al, 2007)

   Protoplasmic fusion or also called somatic hybridization is a hybridization that can be carried out between genus or families which is difficult to occur in conventional hybridization. Protoplasm is a plant cell that has  cell wall removed, leaving only cells covered by a plasma membrane. Protoplasm in plants can come from all parts of the plant, both somatic and reproductive, such as pollen. Protoplasmic fusion can fuse more than two protoplasm either naturally/spontaneously or intentionally with an inducing agent. Spontaneous protoplasmic fusion can occur in the protoplasmic isolation process. Which when the use of enzymes to degrade the cell wall occurs spontaneous fusion protoplasm adjacent to each other to produce multi-nucleate protoplasm. Meanwhile, induction of protoplasmic fusion requires an agent to stimulate fusion known as a fusagen.

     There are three methods of induction of fusion, namely mechanical, chemical and electro.

1. Mechanical fusion is done by physically bringing the protoplasm closer using a micropipette under a microscope. Mechanical fusion is less applicable because the frequency of fusion is lower than other techniques.

2. Chemofusion is a fusion technique using chemicals as fusion agents. Several chemicals that have been used as fusagens are sodium nitrate, polyethylene glycol, calcium ion, lysozyme, dextran sulphate and concavalin. Fusagen acts as a cause of agglutination of each protoplasm which will be followed by fusion. Even so, fusion with the help of chemicals has results that are not controlled with a very high level of variation. On the other hand, chemicals also have the potential to leave toxic residues for plants or cytotoxic.

3. Electrofusion is a fusion technique using high-voltage electricity in a very short time. Electrofusion has advantages over fusion in other ways, namely results that are easier to control, high fusion frequency, non-toxic to living things but require high-tech equipment which is quite expensive.

     Protoplast fusion has been used to combine genes from different organisms to create strains with desired properties. These are the powerful techniques for engineering of microbial strains for desirable industrial properties. Protoplast fusion would continued to be an existing area of research in modern biotechnology.

References:

F. Liu, et al. 2007. Culture and fusion of pollen protoplasts of Brassica oleracea L. var. Italica with haploid mesophyll protoplasts of B. rapa L. ssp. pekinensis. Protoplasma

Nurhasanah; & Sunaryo, Widi. 2019. Fusi Protoplas. Bogor:PT Penerbit IPB Press

Verma, N., M. C. Bansal, & Kumar, V. Protoplast Fusion Technology and Its Biotechnological Applications.