Tree Genetics and Molecular Breeding 2025, Vol.15, No.5, 185-191 http://genbreedpublisher.com/index.php/tgmb 188 4.3 Systems biology approaches for network-level understanding Systems biology methods, by integrating multi-omics data, can construct an aroma metabolism network to understand the formation mechanism of loquat aroma as a whole. KEGG annotation and metabolic pathway enrichment analysis indicated that metabolic pathways such as phenylpropane, flavonoids, and terpenoids constituted the gene-enzyme-metabolite network related to the aroma of loquat. Network analysis not only reveals key metabolic nodes and regulatory factors, but also predicts new functional genes and potential regulatory mechanisms. For instance, the expansion of gene families is often associated with the accumulation of high-abundance aroma substances. The results of systems biology provide theoretical references for the improvement of the aroma quality of loquat and molecular breeding (Wang, 2021). 5 Environmental and Postharvest Influences on Aroma Profiles 5.1 Effects of cultivation conditions: soil, climate, altitude The aroma components of loquats can be affected by the environment. Soil type, climatic conditions (such as temperature and precipitation), and altitude all affect the accumulation of sugar, organic acids, and volatile organic compounds (VOCs) in fruits, thereby altering their flavor and aroma. For instance, an appropriate supply of minerals (such as spraying exogenous boron) can significantly increase the soluble sugar content in fruits, reduce the level of organic acids, and improve the sugar-acid ratio and flavor quality. Changes in cultivation conditions can also affect the activity of related enzymes and gene expression, thereby regulating the synthesis and degradation of aroma precursor substances (Ali et al., 2022). 5.2 Postharvest handling, storage, and ripening regulation Post-harvest treatment and storage methods can also alter the aroma of loquats. During the normal temperature shelf life, some esters and ketones in the fruit (such as ethyl acetate, methyl 3-methylbutyrate, dimethyl ketone) will gradually decrease, while some aldehydes and furans (such as (E) -2-heptenal, heptanal, 2-pentylfuran) will increase, resulting in changes in the overall aroma. Although low-temperature storage can extend the shelf life, it is prone to cold damage and lignification, which affects the flavor and commercial value. By adopting methods such as modified atmosphere packaging, low-temperature regulation, heat treatment or edible coating, the deterioration of quality can be slowed down to a certain extent and the aroma and nutrition can be maintained (Huang et al., 2023; Shah et al., 2023; Zhao, 2024). 5.3 Epigenetic and stress-related modulation of aroma metabolism Environmental stress (such as high temperature, mechanical damage and pathogen infection) and epigenetic regulation may also affect the aroma metabolism of loquats. Stress can induce changes in the expression of metabolic pathway genes, thereby altering the synthesis and degradation of volatile aroma substances. At present, there are few epigenetic studies on the aroma metabolism of loquat. However, existing studies have found that some post-harvest treatment methods (such as heat treatment and controlled atmosphere storage) can indirectly affect the accumulation of aroma substances by regulating the activities of related enzymes and gene expressions (Ali et al., 2022; Shah et al., 2023). Further research on the role of epigenetic mechanisms such as DNA methylation and histone modification in aroma regulation is still needed in the future. 6 Case Study: Metabolomic Profiling of Aroma Compounds in Eriobotrya japonica 6.1 Research background and objectives Loquat is not only an important fruit tree, but also its flowers, leaves and roots hold significant positions in traditional medicine due to their rich content of active ingredients. Aroma is a key factor in evaluating the quality of loquat fruits and flowers and determining consumer acceptance. However, at present, the metabolic characteristics and molecular basis of aroma compounds have not been systematically revealed. The objective of this study case is to comprehensively analyze the aroma-related metabolites in different tissues of loquat using metabolomics methods, understand their composition and distribution, as well as their effects on sensory quality, thereby providing a theoretical basis for the improvement of aroma quality and the development of functional components of loquat (Kuwahara et al., 2014; Kuwahara and Asano, 2018; Wang, 2021).
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