The genome-wide transcriptional consequences of the nullisomic-tetrasomic stocks for homoeologous group 7 in bread wheat

Abstract

BackgroundHexaploid bread wheat (Triticum aestivum L) arose by two polyploidisation events from three diploid species with homoeologous genomes. Nullisomic-tetrasomic (nulli-tetra or NT) lines are aneuploid wheat plants lacking two and adding two of six homoeologous chromosomes. These plants can grow normally, but with significantly morphological variations because the adding two chromosomes or the remaining four chromosomes compensate for those absent. Despite these interesting phenomena, detailed molecular mechanisms underlying dosage deletion and compensation in these useful genetic materials have not been determined.ResultsBy sequencing the transcriptomes of leaves in two-week-old seedlings, we showed that the profiles of differentially expressed genes between NT stocks for homoeologous group 7 and the parent hexaploid Chinese Spring (CS) occurred throughout the whole genome with a subgenome and chromosome preference. The deletion effect of nulli-chromosomes was compensated partly by the tetra-chromosomes via the dose level of expressed genes, according to the types of homoeologous genes. The functions of differentially regulated genes primarily focused on carbon metabolic process, photosynthesis process, hormone metabolism, and responding to stimulus, and etc., which might be related to the defective phenotypes that included reductions in plant height, flag leaf length, spikelet number, and kernels per spike.ConclusionsThe perturbation of the expression levels of transcriptional genes among the NT stocks for homoeologous group 7 demonstrated the gene dosage effect of the subgenome at the genome-wide level. The gene dosage deletion and compensation can be used as a model to elucidate the functions of the subgenomes in modern polyploid plants.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5421-3) contains supplementary material, which is available to authorized users.

Wheat-Thinopyrum Substitution Lines Imprint Compensation Both From Recipients and Donors

“…Moreover, we observed strong apparent transcriptional compensation, based on the significantly greater number of upregulated DEGs in wheat compared with the number of downregulated DEGs (Figure 1D). We found that the compensatory transcriptional effects almost all the wheat chromosomes not just incomplete compensation supported by a study using nullisomic-tetrasomic wheat lines (Zhang et al, 2019). Notably, the corresponding homologous chromosomes showed a higher proportion of upregulated DEGs than other chromosomes (Figure 1D).…”

Positional‐based cloning ‘fail‐safe’ approach is overpowered by wheat chromosome structural variation

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