Tree Genetics and Molecular Breeding 2025, Vol.15, No.5, 185-191 http://genbreedpublisher.com/index.php/tgmb 189 6.2 Methodology: sampling, analytical platform, data analysis This case study selected the flowers, leaves and roots of representative varieties such as ‘Big Five-pointed Star’. Metabolite detection utilized high-throughput platforms such as UKC-ESI-MS /MS and GC-MS. The analysis of aroma components combined GC-O, odor activity value (OAV) assessment and chemometrics methods. Data processing included multivariate statistical analyses such as PCA and OPLS-DA to reveal the differences in aroma metabolism among different tissues and varieties, as well as their relationships with sensory characteristics (Kuwahara et al., 2014; Kuwahara and Asano, 2018; Wang, 2021). 6.3 Key findings: identified aroma compounds and their contribution to sensory quality A total of 577 metabolites were detected by metabolomics, including 98 phenolic acids, 95 flavonoids, 28 terpenoids, as well as various phenylpropanoids and glycosides (Wang, 2021). Among the aroma substances, the main volatile components of the flower are (2-nitroethyl) benzene, p-methoxybenzaldehyde and methyl p-methoxybenzoate. These benzoic acid compounds endow loquat flowers with a unique sweet aroma (Kuwahara et al., 2014; Kuwahara and Asano, 2018). In addition, phenylpropanoids (such as chlorogenic acid, p-coumaric acid), flavonoids (such as quercetin, kaunferol), and terpenoids (such as oleanolic acid, ursolic acid) are abundant in different tissues and are closely related to physiological activities such as antioxidation and anti-inflammation (Wang, 2021; Zhang et al., 2024; Kim et al., 2025). The distribution of aroma substances in different tissues is significantly different: the content of benzoic acid and phenylpropanoids in flowers is relatively high; The leaves and roots are mainly composed of flavonoids, phenolic acids and triterpenoids (Wang, 2021). Some substances (such as (2-nitroethyl) benzene) have only been detected in flowers and are the main source of floral fragrance (Kuwahara et al., 2014; Kuwahara and Asano, 2018). Genomic and transcriptomic studies have also identified some key structural genes and transcription factors, which are involved in the biosynthesis of aroma substances and provide a molecular basis for understanding their metabolic regulatory mechanisms (Koeduka et al., 2016; Wang, 2021; Zhang et al., 2024). 7 Challenges and Limitations 7.1 Difficulties in capturing low-abundance volatiles Although the commonly used metabolomics methods at present (such as LC-MS/MS, UKC-ESI-MS /MS) can detect hundreds of metabolites, their sensitivity to low-abundance and highly volatile aroma components is still insufficient. The traditional phytochemical methods are inefficient and have limited throughput, which also makes it difficult to comprehensively detect and accurately quantify some key aroma substances, thereby affecting the integrity and accuracy of the aroma spectrum (Wang, 2021). 7.2 Complexity in linking metabolites to sensory perception Although research has been able to identify many aroma-related metabolites, it is still difficult to directly correlate these substances with actual sensory experiences, such as aroma types and intensities. The content of some metabolites varies significantly among different tissues, but their contribution to the overall aroma remains unclear. In addition, the physiological functions and sensory thresholds of many metabolites have not been systematically studied, so there is still a ‘black box” between metabolomics data and sensory evaluation (Wang, 2021). 7.3 Gaps in functional validation of candidate genes The combined analysis of the genome and metabolome has been able to screen out some candidate genes related to aroma synthesis, but the specific functions and regulatory mechanisms of these genes are mostly still lacking in experimental evidence. Association analysis alone cannot confirm the true function of genes, and the lack of verification methods such as transgenic or gene knockout also limits our in-depth understanding of the aroma synthesis network (Wang, 2021). 8 Future Perspectives 8.1 Advancements in high-resolution metabolomics and real-time aroma analysis With the development of high-resolution mass spectrometry (such as UPLC-ESI-MS/MS) and multi-omics technologies, the detection sensitivity and coverage range of loquat aroma compounds have been significantly
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