|THAPA, RIMA - Purdue University|
|RAINEY, KATY - Purdue University|
Submitted to: Genes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2019
Publication Date: 12/3/2019
Citation: Thapa, R., Carrero-Colon, M., Rainey, K.M., Hudson, K.A. 2019. TILLING by Sequencing: A successful approach to identify rare alleles in soybean populations. Genes 2019. 10(12):1003. https://doi.org/10.3390/genes10121003.
Interpretive Summary: Soybean is the top source of protein meal globally, however soybean meal contains compounds called raffinose family oligosaccharides (RFOs) that prevent the complete digestion of soybean meal in non-ruminant animals. To combat this problem, soybean breeders seek to incorporate new genes that reduce or eliminate RFOs in soybean meal. In this study random mutagenesis to generate new genetic variation was followed by a targeted approach to detect damaging changes in specific genes in the RFO biosynthesis pathway. The method took advantage of high throughput DNA sequencing and could be applied to any crop. A new mutant was recovered from this screen that reduces RFOs to below detectable levels when used in combination with other soybean genes. This work is significant for soybean breeders and feed producers.
Technical Abstract: Soybean seeds produce valuable protein that is a major component of livestock feed. However, soybean seeds also contain the anti-nutritional raffinose family oligosaccharides (RFOs) raffinose and stachyose, which are not digestible by non-ruminant animals. While reducing RFOs in soybean seed has been a goal of soybean breeding, efforts are constrained by limited genetic variability in soybean germplasm. We used the reverse genetics TILLInG-by-Sequencing approach to identify a damaging polymorphism in the RAFFINOSE SYNTHASE3 gene. We demonstrate that this mutation, when combined as a double mutant with mutation in RAFFINOSE SYNTHASE2, eliminates nearly all of the RFOs in soybean seed, and results in increased levels of sucrose.