Mutations in SGT2 and Game 4 genes altered GA content and its biosynthesis gene expression in diploid potatoes



Potato is the third most consumed food crop by humans after rice and wheat. In the potato breeding continuum, breeders face the challenge of reducing anti-nutritional factors such as steroidal glycoalkaloids (SGAs) through recurrent crosses. Despite all efforts, and depending on variety and postharvest handling conditions, some released potato varieties still show high levels of SGA. We developed an EMS mutagenized diploid potato population and phenotyped 246 mutant lines, 21 wild types and 3 commercial varieties for the SGA trait. Sixteen percent of the mutant lines showed lower SGA content compared to the wild type potato lines and the commercial varieties. An ampliseq sequencing was conducted using a panel of 9 target genes including SGT1, SGT2, SGT3, Game 4a, Game 4b, Game 6, Game 7, Game 11, and Game12 to understand the mutational events underlying the low SGA phenotypes. An RNAseq transcriptomic analysis was further conducted in a mutant line showing a low SGA content and in its wild type counterpart to identify the SGA biosynthetic genes whose expression might be altered in mutant lines. Frame shift and missense mutations leading to loss-of-function were identified in SGT2 and Game 4 genes of the EMS-induced mutant lines and correlated alteration of SGA biosynthesis gene expression was observed in the mutant potato lineThe data will be presented and further discussed in the context of generating a large potato pre-breeding germplasm for improving quality and agronomic traits in potato.