Interspecific hybridization can be considered an accelerator of evolution, otherwise a slow process, solely dependent on mutation and recombination. Upon interspecific hybridization, several novel interactions between nuclear and cytoplasmic genomes emerge which provide additional sources of diversity. The magnitude and essence of intergenomic interactions between nuclear and cytoplasmic genomes remain unknown due to the direction of many crosses. This study was conducted to address the role of nuclear-cytoplasmic interactions as a source of variation upon hybridization. Wheat (Triticum aestivum) alloplasmic lines carrying the cytoplasm of Aegilops mutica along with an integrated approach utilizing comparative quantitative trait locus (QTL) and epigenome analysis were used to dissect this interaction. The results indicate that cytoplasmic genomes can modify the magnitude of QTL controlling certain physiological traits such as dry matter weight. Furthermore, methylation profiling analysis detected eight polymorphic regions affected by the cytoplasm type. In general, these results indicate that novel nuclear-cytoplasmic interactions can potentially trigger an epigenetic modification cascade in nuclear genes which eventually change the genetic network controlling physiological traits. These modified genetic networks can serve as new sources of variation to accelerate the evolutionary process. Furthermore, this variation can synthetically be produced by breeders in their programs to develop epigenomic-segregating lines.
Bibliographical noteFunding Information:
We would like to thank Professor S.S. Maan and Professor K. Tsunewaki for the decades of dedicated effort in the development of alloplasmic wheat lines and providing them for use in this study. We are also grateful for all the assistance received from members of the Wheat Germplasm Enhancement and the Hard Red Spring Wheat programs at NDSU. This research was supported by NSF-IOS 1361554 to S.F.K. and Monsanto Beachell-Borlaug International Scholars program supporting A.S. in his graduate studies.
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- Nuclear-cytoplasm interaction