New forms and cultivars of the plants, obtaining by the original techlology of accelerated selection

Abstract

At present obtaining of the plants cultivars, possessing the high level productivity in the changed climate and the expansion of the potent man-caused influence on the environment is very significant. The methods of the classic selection are not sufficient for the solution of this problem, and the researchers employ further and further the gene engineering and DNA technologies, having also disadvantages and not enable to reach the desirable result, when the aim is the obtaining of the cultivar to be resistant to the complex of environmental stressors.

The discovery of exogenous DNAs (e-DNAs) mutagenicity made by Ukrainian ingenious geneticist M.D.Tarnavsky 80 years ago and the investigations of the influence of e-DNAs on the heredity of living organisms were go before to the arising of the modern DNA technologies. In 70-80 years of the past century the numerous investigations of the influence of e-DNAs on the plants heredity were carried in the world laboratories for the purpose to obtain the useful changes. In our laboratory the original technology of accelerated selection, to be found on the natural mechanisms of the genetic information changing are elaborated as the result of the investigations that proceeded for the some decades.

Our technology consist in the using of the preparations of the donor genomic DNA on the stage of germination of the recipients seeds, the individual selecting of the e-DNA concentration and the other conditions of the seeds infiltration, the using also of the e-DNAs preparations alkylated by the three-functional alkylating agent – thiophosphamides (e-DNA(t)), coupling the e-DNA action with the specific stressors followed by the selection of the plants possessing of desired features for the many next generations.    

The aim of the present review is the analysis and the make of resumes of own investigations, dedicated to the obtaining of the new forms of the plants, possessing of heightened adaptability, by exogenous DNAs preparations, discovery of the regularities of hereditary changes, induced by the using of the e-DNAs preparations to obtain the selective important changes in the plants.

1. Obtaining of the new forms of the Solanaceae plants. It is shown the possibility of correction of the chlorophyll deficit tobacco by the using the e-DNA preparation of the wild type tobacco in the first investigations of A. Potopalsky and B. Levenko to be carried out on the tissue culture. It may be the evidence of the genetic transformation by the insertion of the fragment of the donor DNA.

The lines of tomato plants, resistant even to the very high levels of the salting of the substrate, and the high-yielding cultivar of the salt-resistant tomato Ukrainski [Ukrainian] were obtained on the pure line of the tomato cultivar Kyivsky 139 by the using of the DNA of the salt-resistant black nightshade (Certificate of authorship on the plant cultivar № 08077; A.I. Potopalsky, L.N. Yurkevych). The cultivar is polycarpic (the feature of the donor), have the proteins are intrinsic for the black nightshade and the proteins, which were absent neither donor nor recipient. The using of e-DNAs enabled to obtain also the promising potato cultivar Dzvin (Certificate of authorship on the plant cultivar № 1103; A.I. Potopalsky, M.S. Lytovchenko,A.S. Myslovska, M.A.Pika).

By the use of the e-DNAs of the salt-resistant black nightshade and the plasmids

pCAMVNEO,  pTi 8628, the hereditary changes were induced in the tobacco cultivar Krupnolistny 20 as to the content of the chlorophylls and the carotenoids during the development of the plants, the ratios of the content of some pigments, especially chla/chl b, violaxanthin / lutein, the time of the photosynthetic tissues ageing, apart from the salt-resistance. The heritable changes of the abovementioned ratios of the pigments content may be the evidence of the adaptive reorganization in the photosystems, usually taken place as the result of the lightening alteration. The early time of efflorescence, the alteration of the flowers color, the shape of the leaves, the loss of apical domination and the ability to form the numerous lateral shoots were also inherent for the new forms of tobacco.  

2. The mutations obtained in the cereals by the use of e-DNAs. The 16 mutations were obtained for the winter rye Zhytomyrske by the e-DNAs action of the plants and the animal origin, there are the selective important likewise. Among them it should make attention the new forms of the spring plants obtained from the winter forms and the short-stems, persistent to the lodging forms of rye. It is known the mechanisms of adaptation in the cereals to the low temperatures is connected with the homeotic MADS box genes of the winter-spring habitus are able to transit to the other allele state. In our investigation it is possible the allele transition of the gene vrn-1→VRN-1 or the gene VRN-2→ vrn-2. The numerous morphological changes, obtained in the rye simultaneously with the gaining of the spring habitus, may be mediated by the mutations of the homeotic genes belonging to the other class – homeobox genes, which are the universal regulators of the processes of morphogenesis in the plants and the animal kingdom.       

The main factors regulating the length of the stem and internodes are the level of biologically active hibberellins in the vessels tissues and the level of susceptibility to them. The plants height and the features that stipulate the yielding capacity, in cereals are determined by the complex of hibberellins, brassinosteroides and cytokinins. The level of phytohormones in the plants tissues is controlled developmentally and by the signals from the environment, is under regulation of the homeobox genes. The initiation and the development of the adventitious organs (stems, shoots, the branching out of the floriferous stem or the axis of the racemes, the dividing of the leaf plate on the segments, etc.), the chlorophylls content, the starting of anthocyanins biosynthesis are also controlled by homeobox genes. Thus, the altered level of phytohormones may be in the tissues of the obtained new forms of the rye, as the result of the changes in the most important chain of it regulation by the homeobox genes.

The tetrapoid rye became also the object of our study. The cultivar of tetraploid rye Drevlianske was the result of the many year work and was accepted as the State standart for the tetraploid cultivars in Ukraine (Certificate of authorship on the plant cultivar № 248808; A.I. Potopalsky, L.N. Yurkevych).

The promising cultivars of the wheat, the oat, the millet, to be able to yield the high harvests also on the depleted for the nitrogen soils, were obtained by our technology and also the intergeneric hybrids of cereals resistant to the complex of the stressors of the environment. The fundamental freshness of the cereals obtained by the new technology is it possibility for associative atmospheric nitrogen fixation owing to that feature to be received from the wild cereals (the wheat grass, the reed, the arundo donax, etc.) 

3. By the use of the e-DNAs many new forms of the plants were obtained – medical, ornamental and multipurpose. Among them – the cultivar of Echinacea purpurea Poliśka Krasunia [Poliska Beauty] (Certificate of authorship on the plant cultivar № 07012; A.I. Potopalsky, L.N. Yurkevyc ) and the pumpkin cultivar Kavbuz Zdoroviaga (Certificate of authorship on the plant cultivar № 05119; A.I. Potopalsky), such as possessed the morphological features of pumpkin and watermelon, is the medical plant and the important dietary vegetable. Kavbuz Zdoroviaga was obtained by the action of e-DNA of the watermelon on the pumpkin seeds, it is the intergeneric hybrid of the watermelon (Citrullus lanatus) and the large-fruited pumpkin (Cucurbita maxima).It is shown the distinction in the nucleotides content of the genomic DNA of Kavbuz and of the proteins and sugars content in comparison with the donor and the recipient.

Kavbuz Zdoroviaga was used as the one of parental forms in the improved scheme of the selective process elaborated in Institute of Southern Vegetable and Melons NAAS of Ukraine (Hola Prystan, Kherson province). While the crossing with Kavbuz Zdoroviaga, the simple, double and triple fertile hybrids were obtained, and it is the new, elaborated in Institute of Southern Vegetable and Melons NAAS of Ukraine, method of the enrichment of the gene pool of all pumpkins – the participants of the crossing. The new method of the enrichment of the gene pool of pumpkins was defended by the patent of Ukraine for the useful model. The exploiting of this technic enable to create the new, promising for the selection forms of the interspecies hybrids and the precocious cultivar Universal of the large-fruited pumpkins (C. maxima) having universal use.

Conclusions. It is shown the complex and directed character of the changes induced in the plants by the e-DNAs and the prospects of the using of e-DNAs for the accelerated obtaining of the modern cultivars of agricultural, medicinal and ornamental plants, possessing the increased adaptability. The most important features of the new forms of the plants obtained by the using of e-DNAs are its heightened adaptability and productivity.

The hypothetical mechanism of e-DNAs action on the plant heredity is proposed. The analysis of the numerous changes obtained for the various plants enable us to presume that e-DNAs influence on the systems of genome regulation responsible for the adaptation to the changes in the environment. Just by the influence on such genes encoding the key components of such signaling network, pleotropic character of many changes, obtained by e-DNAs using, may be explained. Since the many changes, obtained in the plants by e-DNAs exploration, are identical to the changes underlying by the known mutations of the homeotic genes, belonging to MADS box and homeobox, and (or) by the changes in the systems of the regulation of their expression, it is very likely that homeotic genes encoding the transcription factors and controlling the passing of the separate stages of the development, the tissue and organ identity, the shape of organs and also the genes of the stress signaling, those modulate the tissues and organs development depending on the conditions of the environment, may be the targets of e-DNAs. Among the homeotic genes, homeobox genes are particularly worthy of attention as the most numerous and connected with the responses to various stressors.

Key words: exogenous DNAs, alkylated DNAs, changes of plants hereditary features, selective important features, resistance to the stressors, phytohormones, homeotic genes, homeobox genes