Multiomics integrated with sensory evaluations to identify characteristic aromas and key genes in a novel brown navel orange (Citrus sinensis)

'Zong Cheng' navel orange (ZC) is a brown mutant of Lane Late navel orange (LL) and emits a more pleasant odor than that of LL. However, the key volatile compound of this aroma and underlying mechanism remains unclear. In this study, sensory evaluations and volatile profiling were performed throughout fruit development to identify significant differences in sensory perception and metabolites between LL and ZC. It revealed that the sesquiterpene content varied significantly between ZC and LL. Based on aroma extract dilution and gas chromatography-olfactometry analyses, the volatile compound leading to the background aroma of LL and ZC is Dlimonene, the orange note in LL was mainly attributed to octanal, whilst valencene, beta-myrcene, and (E)-beta-ocimene presented balsamic, sweet, and herb notes in ZC. Furthermore, Cs5g12900 and six potential transcription factors were identified as responsible for valencene accumulation in ZC, which is important for enhancing the aroma of ZC.