German Version

FAIR 3889

Virus diseases

Phytoplasma diseases

Pathogen collection

Pathogen detection

Pathogen elimination

Contact us

Related Sites

At the IAM, pathogen elimination is usually carried out by in vitro thermotherapy combined with meristem culture. Compared to other methods like conventional thermotherapy or application of antibiotics a higher success rate and simultaneous elimination of viruses and phytoplasmas can be achieved.

In vitro thermotherapy consists of the following steps:

Preparation for therapy

After surface sterilization of selected budwood axenic cultures are established on appropriate culture media.

Heat treatment

Three weeks after subculture in vitro shoots are transferred to a special growth chamber and grown at an increased temperature regime for 14 to 21 days.
There exist clear differences in requirement for Malus and Prunus: Malus tolerates 38° C throughout the treatment, while for Prunus night temperature must be lowered to 36° C to allow plant survival.

Meristem preparation and post therapy maintainance

Apical meristems with 2 - 3 leaf primordia and a size of approximately 0.2 mm are excised immediately after heat treatment and grown on regeneration media.

Regeneration of small plantlets occures within a few weeks. Afterwards, several tests for presence or absence of pathogens are carried out. Pathogen free lines are selected and propagated further. The cultivar is included to a virus-free genebank in vitro.

Acclimatization

Plantlets are rooted in vitro and transferred to the greenhouse. After careful hardening potted plants are re-tested for their pathogen-free status. For budwood production plants are transferred to an insect proof screenhouse.

1. Adams A. N., and Davies D. L., 1992. The elimination of mycoplasma-like organisms from pear budwood by hot water treatment. Acta Hort. 309: 271-274.

2. Laimer M., da Câmara Machado A., Hanzer V., Himmler G., Mattanovich D. und Katinger H.W.D. 1988. In-vitro Vermehrung der alten Lokalsorte von Malus domestica ´Graf Uhlhorns Augustkalvill´. Mitt. Klosterneuburg 38 : 105 - 107

3. Laimer M., da Câmara Machado A., Hanzer V., Weiss H., Mattanovich D., Himmler G. und Katinger H.W.D. 1988. In-vitro Kultur zur Virusfreimachung alter Apfelsorten. Mitt. Klosterneuburg, 38 : 247 -249

4. Laimer da Câmara Machado M., da Câmara Machado A., Hanzer V., Kalthoff B., Weiß H., Mattanovich D., Regner F., Katinger H. 1991. A new, efficient method for the initiation and establishment of tissue cultures of apple from adult material. PCTOC 27:155-160

5. Knapp E., Hanzer V., Weiss H., da Câmara Machado A., Wang Q., Weiss B., Katinger H. and Laimer da Câmara M. 1995. New aspects of virus elimination in fruit trees. XVI ISHS Symposium on Fruit Tree Viruses. Rome. Acta Hort 386: 409-418.

6. Knapp E., da Câmara Machado A., Pühringer H., Wang Q., Hanzer V., Weiss H., Weiss B., Katinger H. and Laimer da Câmara M. 1995. Localization of fruit tree viruses by immuno-tissue printing in infected shoots of Malus and Prunus sp.. J. Virol. Meth. 55(2): 157-173.

7. Knapp E., Hanzer V., Weiss H., da Câmara Machado A., Wang Q., Weiss B., Katinger H. and Laimer da Câmara M. 1995. Distribution of ACLSV in apple shoots cultivated in vitro. XVI ISHS Symposium on Fruit Tree Viruses. Rome, 1994. Acta Hort 386: 187-194.

8. Knapp E., Hanzer V., Mendonça D., da Câmara Machado A., Pühringer H., Katinger H. and Laimer da Câmara Machado M. 1996. Comparison of different treatments for elimination of PPV from stone fruit tissue culture. Proceedings of the ´3. Middle European Meeting on PPV´, October 1996, Budapest. 80-84.

9. Laimer da Câmara Machado M. 1996. Contribution to FAO/IPGRI Guidelines for the Safe Movement of Germplasm: Stone Fruits (nr. 16). eds. M. Diekmann and C.A. Putter.

10. Knapp E., Hanzer V., Weiss, H., da Câmara Machado A., Katinger H. and Laimer da Câmara Machado M. 1997. Characteristics of large-scale production of phytosanitary improved in vitro fruit tree cultivars using in vitro elimination treatments and serodiagnostics. in: Diagnosis and Identification of Plant Pathogens. (editors: Dehne H., Adam G., Diekmann M., Frahm J., Mauler-Machnik A and Van Halteren P) Kluwer Academic Publishers. Developments in Plant Pathology Nr 11: 141-147.

11. da Câmara Machado A., Knapp E., Hanzer V., Arthofer W., Mendonça D., Lopes S., Katinger H. and Laimer da Câmara Machado M. 1998. Phytosanitary improvement of fruit trees: diagnostic strategies in virus indexing of in vitro plants. Intl. Symp. on Fruit Tree Viruses. June 1997. Beltsville, Acta Hort. 472: 511-516.