The Impact of Genomic Interactions on Gene Expression in a Wheat-Barley 7HL Addition Line

Alien gene transfer has been practiced for more than a century as a way to improve wheat by introducing agronomic favourable genes or alleles from its relatives, wild or cultivated. However, only very few wheat-alien introgressions have made their way into practical use in agriculture, due to genetic incompatibility between wheat and its relatives. Despite a keen interest in transferring favourable agronomical traits from barley (earliness, salt tolerance and drought tolerance) into wheat, very few wheat-barley introgression lines have been reported. In order to characterize changes in the function of a gene transferred into a different genome, we performed a RNA-seq analysis using a wheat-barley ditelosomic addition line 7HL, together with the host hexaploid wheat cv. Chinese Spring and the 7HL donor barley cv. Betzes. Comparison of the expression of barley genes in their own genetic background and in wheat background revealed extensive down-regulation of the 7HL genes in the addition line. On the other hand, only a small fraction of the wheat host genes had altered expression in the addition line carrying the chromosome 7HL of barley, with 490 genes being down-regulated and 243 genes up-regulated. However, this small effective account with important components of central metabolic and stress related pathways for the plant, such as carbohydrate metabolism, photosynthesis, and heat-shock response. The analysis of the gene networks affected by the changes in expression of the wheat and barley genes in the ditelosomic addition line 7HL, provide a basis for understanding the effects of alien gene transfers into wheat.