Allelic state and effects of VRN genes on soft wheat in in vivo and in vitro systems

Abstract

The article investigates the effects of the main manifestations of the genetic system controlling the type and rate of wheat development – VRN (vernalization) at the level of an integrated system of plant organism in vivo and callus certain population of cells in vitro. The paper studies the system of allelic VRN genes, which determine the need or insensitivity Triticum aestivum L. to vernalization and predetermination process of callusogenesis by the present system in vitro. In the experiments the modern model system of nearly isogenic lines (NILs) of spring type was used. The NILs were created in genotypes of the winter varieties Myronivska 808 and Olvia. Molecular genetic analysis of allelic loci of VRN genes was carried out by PCR analysis on grains and secondary callus culture using five pairs of specific primers (Grain Gene Mass Wheat). In the course of the experiments, it was found that the genetic system controlling the wheat rate determined the frequency of callusogenesis. However, the studied genetic system did not affect the morphological characteristics of primary and secondary callus tissue. In both hexaploid wheat cultivars the maximum frequency of callusogenesis appeared to be characterized in the Vrn 2 isogenic line and the original variety, slowly developing and intensely accumulating vegetative mass in vivo. The minimal frequency of callusogenesis was determined in the VRN 1 and VRN 3 isogenic lines, characterized by the rapid development of vegetation. The callus was derived from immature wheat embryos by morphological features analysis. Calluses with low water content, mainly, amorphous, compact, transparent, white or with yellowish tint were identified. Using PCR analysis, in grains in vivo and in the callus culture in vitro the almost identical allelic status of VRN genes was revealed. In grains and callus of Vrn 1 isogenic lines of both wheat varieties the presence of a dominant gene VRN A1 and recessive VRN B1 and VRN D1 was detected, whereas in VRN 2 – a dominant gene VRN B1 and recessive VRN A1 and VRN D1. However, the dominant allele VRN D1 in the studied NILs was detected. Therefore, in varieties of grains and callus cultures all genes are represented only by recessive alleles VRN A1, VRN B1 and VRN D1. Differences were found in the callus culture of VRN 3 isogenic line of Myronivska 808 on the allelic state of theVRN B1 gene. The obtained results could be associated with genomic reconstructions during callusogenesis induction. Our studies indicate the unidirectional system of VRN genes functioning, which appears to be the main control system of type and rate of soft wheat development in the system in vivo and in vitro. This allows us to assume the role of the VRN genetic system in the determination of callusogenesis, and also the adequacy of the functioning of the system in vitro processes, determining the system of integration of plants. Thus, our study confirms that the callus tissues cells of higher plants are able to preserve the cells properties of the whole organism along with the acquisition of new specific properties. Moreover, the culture in vitro is an adequate system for the study of the plant organism properties as a system.