Citrus fruits, cherished globally for their flavour and health benefits, are a treasure trove of secondary metabolites such as carotenoids, flavonoids, and terpenoids. These compounds not only shape the fruit's taste and appearance but also serve as powerful phytochemicals with numerous health benefits.

Despite their significance, the genetic control of these metabolites has long remained a mystery. As these compounds play a pivotal role in both human health and fruit quality, unravelling their biosynthetic pathways is essential for advancing citrus breeding and improving cultivar traits. In collaboration with leading institutions such as the Chinese Academy of Agricultural Sciences (CAAS) and the Citrus Research Institute (CRI), a team of researchers has delivered a comprehensive metabolic analysis of citrus species. Their findings (DOI: 10.1093/hr/uhad267), published in Horticulture Research on December 19, 2023, detail a metabolite-based genome-wide association study (mGWAS) conducted on 154 pummelo accessions.

This analysis uncovers the genetic and biochemical underpinnings of metabolomic diversity, with a focus on the phenylpropanoid pathway, a central hub for flavonoid and other bioactive compound production. By employing state-of-the-art metabolomics tools, including two-dimensional gas chromatography/time-of-flight mass spectrometry (GC×GC/TOF-MS) and ultra-performance liquid chromatography-ion mobility spectrometry-quadrupole time-of-flight mass spectrometry (UPLC/IMS/QTOF-MS), the researchers identified and quantified a wide array of metabolites. Their work highlighted the complexity of the phenylpropanoid pathway, emphasizing flavonoid derivatives essential for colour, taste, and health benefits. Among the key discoveries were three BAHD malonyltransferases, enzymes critical for stabilizing flavonoid glycosides, and the R2R3-MYB transcription factor CgMYB1, which plays a vital role in regulating phenylpropanoid metabolism.

These insights provide a robust framework for understanding citrus metabolite diversity and its genetic regulation, paving the way for targeted breeding programs.“This research not only enriches our understanding of the metabolic regulatory networks governing bioactive components in citrus but also showcases an efficient methodology for dissecting complex metabolic pathways,” explained the lead researcher. “Our findings could significantly influence breeding strategies aimed at enhancing the nutritional value of citrus fruits.”The study’s findings have broad implications for agriculture and public health.

By deciphering the genetic basis of metabolite synthesis, scientists are now equipped to develop citrus varieties with enhanced health-promoting properties. These advancements promise to yield fruits with superior nutritional profiles, benefiting consumers and strengthening the agricultural industry. This research marks a pivotal step toward a more strategic and health-oriented approach to citrus cultivation, heralding a new era of nutrient-rich, flavour-packed citrus varieties.

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References

DOI

10.1093/hr/uhad267

Original Source URL

https://doi.org/10.1093/hr/uhad267

About Horticulture Research

Horticulture Research is an open-access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2022. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.