Regions of Chromosome 2A of Bread Wheat (Triticum aestivum L.) Associated with Variation in Physiological and Agronomical Traits under Contrasting Water Regimes.

Understanding the genetic architecture of drought tolerance is of great importance for overcoming the negative impact of drought on wheat yield. Earlier, we discovered the critical role of chromosome 2A for the drought-tolerant status of wheat spring cultivar Saratovskaya 29. A set of 92 single-chromosome recombinant double haploid (SCRDH) lines were obtained in the genetic background of Saratovskaya 29. The lines carry fragments of chromosome 2A from the drought-sensitive cultivar Yanetzkis Probat. The SCRDH lines were used to identify regions on chromosome 2A associated with the manifestation of physiological and agronomical traits under distinct water supply, and to identify candidate genes that may be associated with adaptive gene networks in wheat. Genotyping was done with Illumina Infinium 15k wheat array using 590 SNP markers with 146 markers being polymorphic. In four identified regions of chromosome 2A, 53 out of 58 QTLs associated with physiological and agronomic traits under contrasting water supply were mapped. Thirty-nine candidate genes were identified, of which 18 were transcription factors. The region 73.8-78.1 cM included the largest number of QTLs and candidate genes. The variation in SNPs associated with agronomical and physiological traits revealed among the SCRDH lines may provide useful information for drought related marker-assisted breeding.

Choice of the Promoter for Tissue and Developmental Stage-Specific Gene Expression.

Transgenic technologies belong to important tools of reverse genetics and biotechnology in plants. Targeted genetic modifications can reveal functions of genes of interest, change metabolic and regulatory pathways, or result in accumulation of valuable proteins or metabolites. However, to be efficient in targeted genetic modification, the chimeric gene construct should be designed properly. In particular, the promoters used to control transgene expression need to be carefully chosen. Most promoters in widely used vectors belong to strong and constitutively expressed variants. However, in many cases transgene expression has to be restricted to certain tissue, stage of development, or response to some internal or external stimuli. In turn, a large variety of tissue-specific promoters have been studied and information on their characteristics may be recovered from the literature. An appropriate promoter may be selected and used in genetic construct to optimize the transgene transcription pattern. We have previously designed the TGP database (TransGene Promoters, http://wwwmgs.bionet.nsc.ru/mgs/dbases/tgp/home.html ) collecting information from the publications in this field. Here we review the wide range of noncanonical tissue-specific and developmentally regulated promoters that might be used for transgene expression control.

Simple database to select promoters for plant transgenesis.

The experiments with transgenic plants frequently demand selection of promoters providing appropriate transcription patterns. The set of promoters commonly used in vectors and genetic constructs is very limited, and these promoters provide only a few variants of gene expression patterns. Moreover, identical promoters in a complex construct can induce transgene silencing. This problem can be solved using a variety of plant gene promoters with experimentally verified characteristics. However, this requires a time-consuming analysis of literature data. Here, we describe a database of plant promoters (TransGene Promoters, TGP; http://wwwmgs.bionet.nsc.ru/mgs/dbases/tgp/home.html ). TGP contains the information on genomic DNA segments providing certain expression patterns of reporter genes in experiments with transgenic plants. TGP was constructed on the SRS platform, and its interface allows users to search for the promoters with particular characteristics.

Application of filter technology in photomorphogenesis gene network.

Light regulates almost all physiological and biochemical processes in plants. Plants react to quantitative and qualitative light characteristics owing to the system of photoreceptors and a branched network for light signal transduction. Comprehensible visual representations of gene networks using of filter technology in the GeneNet system assist understanding the types of the relationships between the components inside the networks and to define their hierarchical structure.