Аннотация:Coilin is the main scaffold protein of the Cajal bodies. Cajal bodies are the subnuclear structures which are physically and functionally associated with the nucleolus. Coilin provides the formation and functioning of Cajal bodies which involved in the metabolism of small RNAs. Fibrillarin is one of the major proteins of the nucleolus. It plays essential role in ribosome biogenesis including pre-rRNA processing, methylation of rRNA and snRNAs.In the present study we investigate the role of coilin/fibrillarin in the resistance to abiotic stresses. We used the wild-type Nicotiana benthamiana plants and transgenic plants with "decreased" expression of the coilin or fibrillarin gene. Leaf discs were vacuum-infiltrated into a hyperosmotic medium(250 мМ NaCl)or medium containing H2O2 (0,1 и 0,01%).Transgenic plants were more resistant to both types of stresses. Discoloration of the leaf in wild-type plants was detected a few days earlier. In the following experiment, we studied the resistance to hyperosmotic stress of whole plants.The plants were watered with 50 ml of a solution containing 300 mM NaCl. The degree of loss of the turgor leaves and the number of leaves that lost the turgor, were used as a criterion characterizing the sensitivity of plants to stress. The wild-type plants have more leaves with a lowered turgor (average three leaves, some reached five-six) than transgenic plants (usually two lower leaves).Furthermore, wild-type plants under the abiotic stress passed to flowering several days earlier than transgenic plants and control plants (plants with a similar regime of watering without salt). Based on the obtained results, we assume that coilin and fibrillarin are involved in the formation of the plant's response to abiotic stress. Decreased expression of the gene coilin/ fibrillarin led to an increase in plant resistance to abiotic stress factors.
This work was supported by Research Grant No. 14.W03.31.0003 from the Government of the Russian Federation.