Downregulation of the expression of subgenomic chromosome A7 genes promotes plant height in resynthesized allopolyploid Brassica napus

Theor Appl Genet. 2023 Dec 18;137(1):11. doi: 10.1007/s00122-023-04510-y.ABSTRACTHomoeolog expression bias and the gene dosage effect induce downregulation of genes on chromosome A7, causing a significant increase in the plant height of resynthesized allopolyploid Brassica napus. Gene expression levels in allopolyploid plants are not equivalent to the simple average of the expression levels in the parents and are associated with several non-additive expression phenomena, including homoeolog expression bias. However, hardly any information is available on the effect of homoeolog expression bias on traits. Here, we studied the effects of gene expression-related characteristics on agronomic traits using six isogenic resynthesized Brassica napus lines across the first ten generations. We found a group of genes located on chromosome A7 whose expression levels were significantly negatively correlated with plant height. They were expressed at significantly lower levels than their homoeologous genes, owing to allopolyploidy rather than inheritance from parents. Homoeolog expression bias resulted in resynthesized allopolyploids with a plant height similar to their female Brassica oleracea parent, but significantly higher than that of the male Brassica rapa parent. Notably, aneuploid lines carrying monosomic and trisomic chromosome A7 had the highest and lowest plant heights, respectively, due to changes in the expression bias of homoeologous genes because of alterations in the gene do...

Source: TAG. Theoretical and Applied Genetics - December 18, 2023 Category: Genetics & Stem Cells Authors: Kanglu Zhao Jing Dong Junxiong Xu Yanbo Bai Yuhe Yin Chunshen Long Lei Wu Tuanrong Lin Longqiu Fan Yufeng Wang Patrick P Edger Zhiyong Xiong Source Type: research