plant hormones and genotypic variation in Diospyros kaki in vitro culture

In the scientific paper ‘Diospyros kaki L. Plant regeneration via in vitro leaf derived callus’ (F. Sutter, 2009) an experiment with the aim to figure out the suitability of Diospyros kaki to a milder climate is described.

For this experiment a combination of the following plant hormones is used.

Trans-Zeantin, a naturally occurring cytokine, is induced to simulate cell division and shoot formation.

Thidiazuron is neither an auxin nor a cytokinin.  “TDZ (Thidiazuron) has shown both auxin and cytokinin like effects, although chemically it is totally different from commonly used auxins and cytokinins.” (African Journal of Biotechnology, B. Guo et al., 2011)

IAA (indole-3-acetic acid), a major auxin involved  in many physiological processes of plants.

IBA (indole-3-butyric acid) is an auxin used to promote the formation of roots.

Apart from genotypic variation the replication of Diosparos kaki via in vitro leaf derived callus was successful.  Genetic variation in callus cultures due to mutation occurs often and is called somaclonal variation.

Somaclonal variation has positive and negative effects. It mainly depends on the aim of the wok what the advantages and disadvantages are. If your target is to produce as many identical plants of one individual with ideal qualities, somaclonal variation is not wished and have a major economic impact on this industrie. On the other hand, somaclonal variation is wished when the aim is to produce plants with new quantities like disease resistance, improvement of nutritional quality, adaptation of plants to stress conditions, resistance to herbicides etc.

Sutter mentioned that further trials with frost tolerant and early maturing cultivars are planned. Somaclonal variation could help to achieve this qualities.

Some facts for somaclonal variation:

- Somaclonal variations may show novel mutations.

- Somaclonal variations may reduce time required for mutation breeding.

- Many somaclonal variants show undesirable features such as reduced fertility, growth rate etc.

- The variation is not always heritable

- Selected clones show unpredictable and uncontrollable variants.

For detecting the variants, computer based automated cell sorting devices can be used to screen cells and separate variant cells automatically. These variant cells can then be destroyed or further regenerated.  This information I have found on http://concerncrisis.blogspot.ch/2009/05/somaclonal-variation.html without any further information about this method. So I don’t know how or if the computer based analysis are practiced in in vitro cultures.

ISSR (Inter-simple sequence repeat) and RAPD-PCR (polymerase chain reaction) are useful techniques for detection of somaclonal variation.

Some changes in the genetic code show visible effects and can easily be detected, others don’t have any effects at all.

In several experiments, scientists bring appearance of somaclonal variation in relation with callus age, hormone application and UV-C radiation. This information could help to decrease or increase genetic variation in in vitro tissue cultures.

Thidiazuron (African Journal of Biotechnology, B. Guo et al., 2011)

http://www.academicjournals.org/ajb/PDF/pdf2011/17Aug/Guo%20et%20al.pdf

Plant hormones to buy with brief information about their effects

www.toku-e.com

General plant hormone information

www.plant-hormones.info

Methoed to detect variants and reasons when it occurs more often

www.genetic-id.com

www.dnalc.org/resources/animations/gelelectrophoresis

http://concerncrisis.blogspot.ch/2009/05/somaclonal-variation.html

http://www.bio21.bas.bg/ipp/gapbfiles/v-33/07_1-2_03-11.pdf