NnLOX1-mediated aroma formation in lotus (Nelumbo nucifera) through multi-omics integration and machine learning

Nelumbo nucifera is widely consumed globally in both medicine and food industry. However, the aroma formation in N. nucifera remains largely unexplored. In this study, a total of 46 different changed metabolites (DCMs) were identified in petal, anther, seed, seedpod, and rhizome from N. nucifera cultivar of "Jinsenianhua". Among these volatiles, Nonanal exhibited the higher relative odor activity value (ROAV) in anther, whereas the lower ROAV of Nonanal was detected in rhizome. Transcription analysis was performed to screen the key lipoxygenase (LOX) involved in synthesis of Nonanal in different tissues, revealing a positive correlation between NnLOX1 transcript and Nonanal accumulation. Transient over-expression of NnLOX1 in tobacco leaves increased Nonanal biosynthesis, which was potentially detected by a wide-range olfactory receptor (ORs) of OR1A2. Our findings highlight the crucial role of NnLOX1 in forming characteristic aroma in various tissues of N. nucifera.