||Development of the technology of plant genetic resources identification and passportization based on the protein markers for effective germplasm collection management
|A.Konarev, V.Konarev, N.Gubareva, I.Gavriljuk, T.Peneva, N.Alpateva, P.Strelchenko, I.Anisimova and S.Farber
To serve effective basis for improvement of cultivated plants stored in the gene banks, genetic diversity should be carefully and comprehensively evaluated and characterised (investigated).
Collections should be rationally organised. Each accession should be identified and registered. The preservation of genetic constitution of
accessions (genetic integrity) is included also into the category of basic problems. The objective of gene bank is to maintain the accession without change as regards its genetic constitution.
It means preservation not only sample as such, but with its valuable properties, in particular adaptive etc. Understanding of genetic structure of biodiversity (relationships inside genepool or
between structural elements of genetic diversity) is the important goal of gene bank activity. That knowledge can be used to facilitate the use of germplasm in the development of modern crop varieties.
Molecular markers (MM) are successfully used on the following steps of working with plant collections (In N.I.Vavilov Institute - protein markers are mainly used):
- search of new allelic diversity for gene banks in situ (exploration of wild-growing diversity);
- originality testing of new accessions before the entry in collections;
- the degree of similarity or difference among individual genotypes in an accession or among accessions in collection;
- structure of collections: number of genetic variation present, intraspecies relations and interspecies relationships (genome analysis);
- identification and registration of genetic diversity (accessions, genotypes) and preparation catalogues and data bases on MM;
- identification of duplicates, very similar accessions and various mistakes in collections;
- development of core collections;
- analysis of accessions genetic constitution (after reproduction and under various storage conditions);
- identification of alien genetic material;
- authorship rights control (for gene bank problems);
Seed proteins in identification and registration of wheat gene pool.
The most significant element in the work of a botanist, geneticist or breeder is identification of species, varieties, biotypes and other biological systems. Identification simplifies documentation of a gene pool of cultivated plants and their wild relatives with the aim of its registration, preservation and effective usage in breeding. It is necessary to reveal and isolate desirable genotypes from complex natural varietal and hybrid populations. Identification of varieties and lines is especially topical for intensification of breeding and seed production, which demand high accuracy and efficiency of seed control (1).
In order to develop a flexible and reliable nomenclature and system of pattern recording, practically all intraspecific (or intrageneric) variability of a given protein marker should be investigated. Due to this total investigation of specific and generic biodiversity, almost all possible locations of protein components can be identified. Cultivars, wild growing populations, landraces from world collections have to be analysed. It was implemented in the N.I.Vavilov Institute, and this principle was laid in the base of nomenclatures and systems of recording electrophoretic components for many crops. This approach was first developed for wheat and then spread on all Triticeae and other crops (1,2).
Wheat gliadin pattern was taken as a basis. The pattern was divided into four zones. Within a zone the main possible positions of components were numbered to the start. By means of such etalon pattern, any variety or biotype of Triticeae may be recorded in the form of prolamin formula. By now cultivated and wild-growing gene pools of wheat, rye, barley and other representatives of Triticeae have been written down in the form of protein formulae; catalogues and data bases of such formulae were released.
Usage of protein markers for testing the genetic constitution of an ex situ collection.
The collection of the N.I.Vavilov Institute comprises a lot of accessions of old varieties (winter bread wheat) and forms with a high level of population polymorphism as compared with modern varieties. The diversity of old varieties and forms is an important source of genetic variability and consequently of valuable traits for wheat improvement. The task of gene bank is to identify, register and store the whole genetic variability of these unique forms. It is known that in the course of long-term storage and reproduction, original populations lose part of their genotypes. One of our goals was to estimate gliadin polymorphism of old wheat varieties and to determine the level of population dynamics during reproduction and storage. Changes in genotype composition during seed multiplication in 1989-1991 were shown for some bread wheat landraces. Simultaneously it was discovered that separate genotypes of these old varieties had lost their germination ability with different rate after 2 to 8 years of storage (3). Practically, heterogenic populations (landraces, old varieties and original forms) require identification of separate genotypes and organization of their individual storage.
Analysis of Triticeae germplasm based on prolamin polymorphism
Genetic diversity of Triticum, Aegilops, Erytrigia, Secale, Hordeum collections stored in VIR was characterized by prolamin polymorphism. The main goals were: identification and registration of the diversity in the form of prolamin formulae, identification of duplicate accessions, formation of core-collections, and differentiation of biodiversity.
The main directions of MM usage for problems of plant breeding.
Marking of genetic systems of different level. Analysis of breeding material:
- search and selection of valuable or desirable genotypes (populations), studying of selection (genetic) material on all steps of plant breeding (MAS);
- studying of population composition (population polymorphism);
- study of the dynamics of population composition (biotypic composition);
- determination of hybridity of seeds;
- analyses of artificial amphydiploids (polyploids) and hybrids prepared by distant hybridisation;
- identification of alien genetic material;
- prediction of species crossibility;
- prediction of the level of heterosis (1,2).
Using MM in seed production and seed testing.
Estimation of originality in initial seed production by identification of typical for this variety biotypes; elucidation of origin of non-typical plants; testing for presence of random cross-pollination or mechanical contamination; control for population composition in course of seed production; control for authenticity of varieties (of seed stock); authorship rights control (1,2).
Possible directions for collaboration:
Elaboration of Improved Technology Based on Molecular Markers for Accelerated Usage of Plant Genetic Resources in Plant Breeding
Possible subdirections for collaboration:
- Creation of databases of plant genetic resources based on reliable molecular and computer technologies
- Creation of the software for effective management of databases and use ofgenetic resources
- Development new effective marker systems (techniques) for identification of various plant genetic resources
- Exploration of certain plant genetic diversity of common interest by protein and DNA markers
- Development and usage of reliable approaches based on molecular markers to identify doublet accessions, to test genetic integrity of accessions.
- Molecular biological aspects of applied botany, genetics and plant breeding. Theoretical basis of plant breeding. (Eds. V.Konarev, A.Konarev). Vol. I. St.-Petersburg, VIR (1996) 228 p.
- Konarev V, Gavriljuk I, Gubareva N and Peneva T. Seed proteins in genome analysis, cuktivar identification and documentetion of cereal genetic resources: a review. Cereal Chem. 56: 272-278 (1979).
- Vvedenskaja I, Alpatyeva , Gubareva N and Konarev A. Use of storage protein electrophoresis in the analysis of genetic resources of some cereals. Erhaltung and nutzung pflanzengenetischer ressourcen - eine internationale aufgabe fur naturschutzer, genbanken und pflanzenzuchter. Vortrage fur pflanzenzuchtung. 25: 187-201 (1993).
- Konarev A., Konarev V. Use of genome specific antigens and prolamine electrophoresis in evaluation of wheat and its relatives. In: "Biodiversity and Plant Improvement". (Ed. A.B.Damania). ICARDA, 1993, p.259-273
- International Rules for Seed Testing. Rules 1996. Verification of species and cultivar. Seed Sci.& Technol., 1996, 24 (Supplement): 253-270.
| Development of the technology of plant genetic resources