Characterization of progeny derived from disomic alien addition lines from intersubgeneric cross between Glycine max and Glycine tomentella

Disomic alien addition lines (DAALs, 2n=42) were obtained from an intersubgeneric cross between Glycine max [L.] Merr. cv. Dwight (2n=40, G1G1) and Glycine tomentella Hayata (PI 441001, 2n=78, D3D3CC). They are morphologically uniform but distinct from either of the parents. These DAALs were all derived from the same monosomic alien addition line (MAAL, 2n=41), and theoretically they should breed true because they had a pair of homologous chromosomes from G. tomentella and 40 soybean chromosomes. However, in some selfed progenies of DAALs the extra G. tomentella chromosomes were eliminated resulting in plants with 2n=40 chromosomes. These progeny lines (2n=40) have a wide variation in phenotypes. The objective of this research was to document the phenotypic and chromosomal variation among the progeny of these DAALs, and to understand the genetics behind this phenomenon. In the replicated field study, variation was observed among the disomic progenies for the qualitative traits such as flower, seed coat, hilum, pod, and pubescence color, and stem termination; as well as the quantitative traits protein and oil concentrations, plant height, lodging, and time of maturity. Three disomic lines had protein concentrations significantly high than either the DAAL or Dwight. Studying the plant transcriptome via RNA-sequencing documented that many genes that are critical to fundamental plant growth processes and related to stress and defense responses were differentially expressed between the DAAL (LG13-7552) and one of the disomic progeny (LG12-7063). RNA-sequencing data indicated that the gray pubescence of LG12-7063 was not due to sequence change from T- to t t genotype, but the result of altered gene expression. The expression of G. tomentella sequences and higher expression of transposable elements (TEs) in the DAAL were also documented