Cytoplasmic Hybrids or Cybrids, Nucleus, Organelles, Cytoplasm, Organelles Enucleated Protoplast, Organelles from both parents, Fused Protoplast

Scholarships Dictionary Visa Details Study Abroad Exam Results Online Test Jobs

	Home
Protoplast Culture Regeneration and Somatic Hybridization Protoplast Culture Regeneration and Somatic Hybridization - Introduction Isolation of Proplasts Mechanical Method Enzymatic Method Direct One Step Method Sequential Two Step Method Purification of Isolated Protoplasts Sedimentation and Washing Flotation Viability and Plating Density of Protoplasts Testing Protoplast Viability Minimum Plating Density MPD and Culturing Individual Protaplasts Protaplast Culture and Regeneration of Plants Isolation of Subprotoplasts Protoplast Fusion and Somatic Hybridization Techniques of Protoplast Fusion

Home >> Plant Biotechnology and Genomics >> Protoplast Culture Regeneration and Somatic Hybridization >> Cytoplasmic Hybrids or Cybrids

Cytoplasmic Hybrids or Cybrids

In sexual hybrids, the cytoplasm is derived from the maternal parent and in somatic hybrids, it is derived from both the parents. However, hybrids can be obtained, where nucleus is derived from one parent and cytoplasm is derived from both, thus producing cytoplasmic hybrids, which are also called cybrids.

These cybrids can be obtained using any one of the following methods:

(i) fusion of normal protoplasts from one parent with enucleated protoplasts from the other parent enucleated protoplasts can be obtained by high speed centrifugation (20,000-40,000g for 45-90 min) of protoplasts or by irradiation treatment;

(ii) fusion of normal protoplasts from one parent and protoplasts containing non-viable nuclei from the other;

(iii) selective elimination of one of the nuclei from the heterokaryons or

(iv) selective elimination of chromosomes of one parent at a later stage after fusion of the nuclei.

A. Formation of a cybrid due to fusion of a normal protplast	B. Protoplasts can be made enucleated by Centrifugation

1. nucleus	5. fused protoplast
2. cytoplasm	6. nucleus from A
3. organelles	7. organelles from both parents
4. organelles (enucleated protoplast)	8. cybrid

The technique of cybrid production has been utilized for transfer of cytoplasmic male sterility as has been successfully done in Nicotiana, Brassica and Petunia.

Other characters like streptomycin resistance have also been transferred from N. tabacum to N. sylvestris, using this technique. CMS lines with ‘Ogura cytoplasm’, a herbicide (atrazine) resistant line and lines with increased nectar production have also been obtained using cybrids in crop brassicas.

Formation of Cybrid due to Exclusion of a Nucleus from the Heterokaryon

1. type I	6. both nuclei persist
2. type II	7. heterokaryon
3. heterokaryon	8. chromosomes of one parent lost
4. fused nucleus	9. cybrid
5. hybrid	10. selective elimination of type II nucleus

	Home
Induced Fusion NaNo₃-treatment Treatment with Calcium Ions ca⁺⁺ at High pH Polyethylene Glycol PEG Treatment Electrical Fusion Selection of Fused Protaplasts Chromosome Status of Somatic Hybrids Interspecific Hybrids Produced Through Protoplast Fusion Intergeneric Hybrids Produced Through Protaplast Fusion Use of Protoplast Fusion and Somatic Hybrids Somatic Hybrids for Gene Transfer Asymmetry in Somatic Hybrids for Gene Transfer Somatic Hybrids for Cytoplasmic Male Sterility Cytoplasmic Hybrids or Cybrids Genetic Modification Transformation of Protoplasts