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Chenopodium quinoa (quinoa) is a potential future major crop. However, one of its major setbacks is that some cultivars produce bitter saponins, which other cultivars do not and hence are called sweet. A previous study has indicated that a single nucleotide polymorphism in the last nucleotide of the third exon in the basic helix-loop-helix (bHLH) transcription factor TSARL1 can cause the sweet phenotype in quinoa cultivars. The purpose of this study was to investigate TSARL1 in five sweet cultivars and Titicaca, a known bitter cultivar that is able to grow in Denmark. To further investigate TSARL1 five bitter cultivars were chosen to be investigated on a genomic level. For this purpose, I examined TSARL1 at the genomic and transcript levels by sequencing the TSARL1. I amplified the TSARL1 gene including its 5’ upstream region from genomic DNA of the sweet cultivars and a total of six bitter cultivars, and subjected it to Sanger sequencing. Likewise, RNA was extracted to carry out reverse transcription (RT)-PCR in order to obtain the coding sequence of TSARL1 in the Titicaca cultivar and the sweet cultivars included in the study. Furthermore, all cultivars were phenotyped to ensure that they were different cultivars. I found that TSARL1 is in fact mutated at the previously reported position in the sweet cultivars of quinoa included in the study, and that the mutation leads to a truncated transcript of TSARL1, most likely because it affects a cryptic splice site within the third exon of TSARL1.

Chenopodium quinoa (quinoa) is a potential future major crop. However, one of its major setbacks is that some cultivars produce bitter saponins, which other cultivars do not and hence are called sweet. A previous study has indicated that a single nucleotide polymorphism in the last nucleotide of the third exon in the basic helix-loop-helix (bHLH) transcription factor TSARL1 can cause the sweet phenotype in quinoa cultivars. The purpose of this study was to investigate TSARL1 in five sweet cultivars and Titicaca, a known bitter cultivar that is able to grow in Denmark. To further investigate TSARL1 five bitter cultivars were chosen to be investigated on a genomic level. For this purpose, I examined TSARL1 at the genomic and transcript levels by sequencing the TSARL1. I amplified the TSARL1 gene including its 5’ upstream region from genomic DNA of the sweet cultivars and a total of six bitter cultivars, and subjected it to Sanger sequencing. Likewise, RNA was extracted to carry out reverse transcription (RT)-PCR in order to obtain the coding sequence of TSARL1 in the Titicaca cultivar and the sweet cultivars included in the study. Furthermore, all cultivars were phenotyped to ensure that they were different cultivars. I found that TSARL1 is in fact mutated at the previously reported position in the sweet cultivars of quinoa included in the study, and that the mutation leads to a truncated transcript of TSARL1, most likely because it affects a cryptic splice site within the third exon of TSARL1.