Creation of new plants. Change of old grades of plants by means of new methods

you are: Creation of new plants

Crossings between existing plants, of course, do not settle all potential possibilities of reception of new combinations genomov. Usual crossings should be continued not only for increase of productivity of agricultural plants and their quality, but also for their protection against new races of microorganisms and insects-wreckers. Besides, it is necessary to develop further new methods in which basis use of fabric and cellular cultures and somatic hybridization by merge of protolayers though all it remains for the present only at level of curious laboratory experiments lie. Recently as a result of merge of protolayers the present somatic hybrid between a potato and a tomato has been received. At cultivation in culture of such hybrid cages the weight of not differentiated fabric (kallus), and then and the whole plants with some signs of both parents in the beginning was formed. To prove the hybrid nature of these plants, from them allocated and analyzed r-bulozobisfosfat-karboksilazu - enzyme of a cycle of Calvin, consisting of big subedinits the squirrel, defined by the genes containing in hloroplastah, and small subedinits, defined by nuclear genes. it has been shown that at a hybrid big and small albuminous subedinitsy occur from different parental individuals. It is the first case, when by somatic hybridization the plant has been created, which is impossible (or anyway it was not possible till now) to receive by means of usual methods of sexual crossing. The method of somatic hybridization will present in the near future to us, undoubtedly, many other unexpectedness.

For experiments on transformation of a vegetative cage by the most suitable object, almost probably, there will be protolayers. We already have a number of the factors, capable to transfer genes from one cage in another; the most promising, from such carriers serves Ti - (tumour inducing) plazmida Agrobacterium tumefaciens (the activator of a cancer of a root neck). This small ring molecule of DNA causing transformation of normal cages in cages of a cancer tumour, it is possible ' to make an incision ' and to open, using restriktsionnye endonukleazy, allocated of various microorganisms. to the ring opened thus plazmidnoj DNA it is possible to add other fragments of DNA received similarly from cages which genes are subject to carrying over. In the presence of corresponding energy sources and the enzymes named ligazami, it is possible to cause connection of the opened ends of molecules of DNA. In certain cases thus turn out hybrid plazmidy, become isolated which ring joins desirable genes eukarioticheskih cages. Such plazmidy it is possible then to use for infection of protolayers of a plant-owner to which it is supposed to transfer these genes.

In case of good luck of experiment plazmida gets into a cage and replitsiruetsja together with chromosomal DNA. Parts plazmidnoj DNA can then be liberated from koltsevidnoj molecules and join in a gene-receptor, having turned to a constant component of the genetic device already the changed plant-owner.

Many plans for carrying out of experiments on carrying over of the genes defining fixing of nitrogen, stability to activators of illnesses, higher aminokislotnuju efficiency and more powerful gabitus Were offered. Though now these plans seem a little fantastic, they should be meant on the future. Gene engineering it will be almost doubtless to play large role in agriculture of XXI century

The Protolayers received from leaves of a potato, already are used for selection of the variants steadiest against adverse influences, and to illnesses (fig. 16.3). The impression is made that each sheet represents a mosaic from the cages differing on the genetic structure these distinctions can be caused gene mutations, such chromosomal changes as deletsii, or it is unequal measured distribution plazmid at cellular division. In what the reason of genetic change consisted, it is possible to allocate these cages in the form of protolayers of which as a result of regeneration at first cages, and then kallusy and the whole plants again are formed; the copies received thus can be investigated to reveal distinctions available between them. This powerful method, obviously, will find wide application in the future.

The Close method - culture of cages at presence antimetabolitov (fig. 16.4). It is necessary to expect that any cage which is grown up at presence antimetabolita, will make superfluous quantity normal metabolita. If such cage to grow up in culture it, probably, will give rise to a plant producing wished metabolit in considerable quantities. Such experiment has been successfully spent with carrots cages. At introduction on Wednesday 5-metiltriptofana (5-MT) the majority of cages perishes, as 5-MT - the effective antagonist triptofana. But some cages thus do not perish; they as it has appeared, contain considerable quantities endogennogo triptofana because enzyme available for them - antranilatsintetaza, participating in formation indolnogo rings triptofana, - does not choke as it usually happens, a reaction end-product. As a result this enzyme causes ' superfluous production ' triptofana, and the plants recycled from such selected cages, more richly triptofanom, than those lines from which they occur. This method, undoubtedly, will be used in the future for creation of lines of the important agricultural plants with the raised maintenance of vitamins, amino acids, steroids and other desirable products developed by plants.