Integrated transcriptomic and metabolomic profiling identifies IbADCL1 as a key regulator of folate biosynthesis in sweet potato storage roots.

We hypothesized that key regulatory genes in the folate biosynthesis pathway could be identified through integrated multi-omics analysis and functionally validated to enhance folate accumulation in sweet potato storage roots. Folate, an essential micronutrient in plant metabolism and human diets, shows poorly characterized accumulation mechanisms in sweet potato storage roots. Comparative profiling of 26 cultivars identified low- (968-19) and high-folate (Y25) varieties. Integrated multi-omics analysis of tuber tissues across developmental stages revealed 5-methyltetrahydrofolate (5-MTHF) and 5-formyltetrahydrofolate (5-FTHF) as principal determinants of folate variation. Differential expression analysis pinpointed IbADCL1, encoding 4-amino-4-deoxychorismate lyase, as a putative regulatory gene. Heterologous overexpression of IbADCL1 in 968-19 triggered 177-222% increases in total folate, with 5-MTHF and 5-FTHF levels elevated by 184-224% and 40-142%, respectively, versus wild-type controls. This study establishes IbADCL1 as a rate-limiting controller of folate biosynthesis, offering molecular targets for metabolic engineering to enhance nutritional quality in sweet potato.