Application of biotechnological methods in conservation of plant genetic resources

 

The Bulgarian flora is a source of plant species rich in a large set of chemical components – specific substances or groups of compounds that are in limited populations. Insufficient amounts of plant material cannot be the basis for satisfying the demand and production of their metabolites by traditional technologies. In the last years of our century, scientists have warned that the loss of biodiversity is increasing. This necessitates the collection and preservation of plant species. Plant genetic resources bring together plant species that provide humanity with everything necessary for life: food, raw materials, and energy. Their preservation is a priority task on a global scale.

The Institute for Plant Genetic Resources „Konstantin Malkov“, city of Sadovo, is registered as the coordinator for plant genetic resources for Bulgaria. The institute is located 20 km east of the city of Plovdiv. It was established in 1902 – as an experimental agricultural station, which in 1977 expanded into the Institute of Plant Genetic Resources, which is the National Coordinator of the Program on Plant Genetic Resources, which is part of the European Program on Plant Genetic Resources (ECPGR) .

The National Genebank is located on the territory, which stores 57,684 seed samples from the total of 62,131 registered as a gene pool in the country (http://eurisco.ecpgr.org). The main scientific directions at the Institute of Plant Genetic Resources „K. Malkov“ – Sadovo are aimed at the collection, study, storage, documentation and use of plant genetic resources. The groups of crops included in ex situ collections are: cereal-cereal, cereal-legume, technical, cereal and leguminous forage grasses, vegetable, decorative and medicinal species. These collections provide opportunities for multifaceted use, which is determined by the available genetic diversity: wild species, local populations, primitive varieties, breeding materials and modern varieties originating from the country and the world.

The long-term storage of the seed samples is carried out at minus temperatures (-18°C) in a specially designated chamber. Vegetatively propagating species of cultivated and wild flora are cultivated under in vitro conditions.

The Laboratory of Plant Biotechnology at Institute of Plant Genetic Resources „Konstantin Malkov“ city of Sadovo was established in 1977 by Prof. Dr. Chavdar Chavdarov. Scientific activity is aimed at in vitro vegetative reproduction, storage and application of selection methods. In vitro varieties are important for practical use in the creation of new and maintenance of old varieties. The goal is to be able to maximally preserve the plant plasma for a long period of time under controlled conditions. The main task of the scientific research work is aimed at introducing in vitro conditions, micropropagation, adaptation and breeding of the species under natural conditions.

For four decades, the largest collection in Bulgaria of the species Solanum tuberosum L. has been built, maintained and renovated. Preservation of the old varieties, populations and forms created through long-term selection and popular selection is of extreme importance. The resulting virus-free material is stored long-term under controlled conditions. The advantages of the method are conservation of the species for a longer period of time and the possibility of extremely fast reproduction if necessary. Various techniques have been investigated for slow growth and reduction of intercultural subculture leading to genetic stability in order to maximize the preservation of the species. Scientific activity for the species is aimed at vegetative reproduction, storage and application of selection methods.

 

 

 

 

 

 

 

 

 

 

 

Photo 1 Long-term storage of Solanum tuberosum L.

With the development of the methods for the induction of callus tissues and the preparation of cell suspension cultures, the extraction of valuable chemical compounds from valuable plant species of the Bulgarian flora can be achieved. Through cell suspension cultures, it allows to search and extract alkaloids, flavonoids, glucosides, steroids, saponins, and others.

In the laboratory, a methodology was developed for processing the plant tissues to a condition for obtaining callus tissues and suspension cultures of Althaea officinalis L., Glycyrrhiza glabra L, Hyssopus officinalis L. and Leaecojum aestivum L. (Photo 2).

 

 

 

 

 

 

 

 

Photo 2 Suspension culture from Leaecojum aestivum L.

 

Based on the activities related to the conservation of Vitis vinifera L. (photo 3) and the use of the cultivated species and its wild predecessor, a collection was formed for long-term storage using growth inhibitors. The survival ability of long-term cultures depends on the genotype and the storage time. This has implications for practical use in creating new and maintaining old vine varieties.

 

 

 

 

 

 

 

 

 

Photo 3 Long-term storage of Vitis vinifera L.

 

The research work on the study and introduction of foreign germplasm of different origins and diverse type of material is also significant. The upgrading of the collections is achieved through expeditions to individual regions in accordance with the tasks of the implemented projects and through international exchange. The in vitro method makes it possible to test the methods of long-term storage of samples of the test cultures without the need for reproduction, which allows long-term maintenance of the collections (photo 4 and 5).

 

 

 

 

 

 

 

 

 

 

 

 

 

Photo 4 Glycyrrhiza glabra L

 

 

 

 

 

 

 

 

 

 

 

Photo 5 Asclepias tuberoza L.

Medicinal and flower plant species specific to Bulgaria – rare, endangered, endemic and disappearing species, as well as wild relatives of cultivated plants – have been introduced into culture in vitro. Species with low germination were studied in response to the nutrient medium. A collection of valuable medicinal (photo 6 and 7) and flower species has been created.

 

 

 

 

 

 

 

 

 

 

 

 

 

Photo 6.  Chrysanthemum carinatum L.

 

 

 

 

 

 

 

 

 

 

 

Photo 7.  Petunia hybrida L.

he wheat selection program is aimed at creating varieties with high productive potential, possessing a complex of biological and economic qualities, resistant to biotic and abiotic stress factors and suitable for cultivation while reducing production costs.

Under the guidance of рrof. Petar Boyadzhiev, the variety „Zdravko“ was created (photo 8). It has good cold resistance and drought resistance thanks to a highly developed and deep root system. It is resistant to the likes of powdery mildew, yellow and brown rust, fusarium and powdery mildew. Applying the methods of anther cultures to rice, the variety „Mariana“ was created.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Photo 8. variety „Zdravko“

 

The technique of microclonal propagation gives great opportunities to maintain the resulting healthy plants for an unlimited period of time and to serve as a source of production of healthy planting material. Combining traditional selection methods with modern biotechnological advances is an opportunity to expand selection in major agricultural crops.

The Plant Genetic Resources Program is an implementer of the Convention on Biological Diversity (1993), the European Biodiversity Policy 2010-2011 and the Global Strategy for Plant Conservation 2011-2020.