How black wolfberry makes its antioxidant armor?

Famed for its deep purple berries and potent antioxidant properties, black wolfberry (Lycium ruthenicum) thrives in harsh desert climates and holds significant nutritional and medicinal value. Yet, the genetic blueprint behind its rich coloration and resilience has long remained a mystery. Now, scientists have successfully assembled a chromosome-level genome of this unique plant and identified the genetic drivers of anthocyanin biosynthesis—compounds responsible for its color and health benefits. Using a powerful combination of genomics, transcriptomics, and metabolomics, the study revealed key genes that influence pigment production, offering new insights into how this desert-adapted species protects itself—and potentially, human health.

Anthocyanins, the natural pigments behind red, purple, and blue hues in plants, are more than just eye-catching. These compounds are powerful antioxidants with applications ranging from disease prevention to natural food colorants. Black wolfberry stands out for its exceptionally high anthocyanin levels—greater than even blueberries or blackcurrants—and has been valued in traditional medicine for its anti-aging, anti-fatigue, and immune-boosting properties. These benefits are matched by its ecological role as a hardy shrub capable of withstanding drought, salinity, and UV exposure. Due to these challenges and its untapped potential, a deeper investigation into its genetic regulation of anthocyanins is urgently needed.

In a study (DOI: 10.1093/hr/uhae298) published on October 23, 2024, in Horticulture Research, researchers from the Ningxia Academy of Agriculture and Forestry Sciences and Nanjing Agricultural University reported a high-quality genome assembly of black wolfberry. Leveraging haploid material and cutting-edge sequencing technologies, they constructed a 2.27 Gb reference genome anchored to 12 chromosomes. Through integrated multiomics analysis, they pinpointed 86 genes associated with anthocyanin biosynthesis and identified five as central regulators. This foundational work opens new doors to understanding the metabolic complexity and environmental resilience of this underexplored plant.

To overcome the plant's high heterozygosity, the team developed haploid lines and used PacBio HiFi and Hi-C sequencing to achieve a highly contiguous genome with over 99% of core genes captured. Comparative genomics revealed that L. ruthenicum and its close relative L. barbarum diverged through structural variations and transposable element expansions, which contributed to the former's larger genome and greater adaptability. By integrating transcriptomic and metabolomic data from different accessions, researchers identified five candidate genes—LrCHS1, LrCHS2, LrF3'5'H, LrAOMT, and the transcription factor LrAN2.1—that were consistently upregulated in the dark-fruited variety 'Heiguo'. These genes showed strong correlations with anthocyanin accumulation and were functionally validated through transient overexpression in L. barbarum. The experiments confirmed their role in promoting or modulating key pigment metabolites, revealing a multi-layered regulatory network. This work not only unravels the genetic underpinnings of black wolfberry's signature color but also sets the stage for future crop improvement.

“This study offers a genomic roadmap for decoding the black wolfberry's unique traits,” said Dr. Jianhua Zhao, senior author of the study. “By identifying the genes directly responsible for anthocyanin production, we can accelerate the development of improved cultivars. These insights also shed light on how plants adapt to environmental extremes, reinforcing the value of genomic tools in sustainable agriculture and health-oriented plant breeding.”

The release of this high-quality genome provides a crucial platform for precision breeding of black wolfberry with enhanced anthocyanin content and stress resistance. The validated biosynthesis genes can also be transferred or edited in other crops to enhance their nutritional and medicinal profiles. Moreover, understanding the genetic basis of this plant's resilience may inform broader strategies in climate-smart agriculture. Beyond the field, its natural pigments have promising commercial applications in functional foods, cosmetics, and pharmaceuticals—serving as a sustainable alternative to synthetic additives.

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References

DOI

10.1093/hr/uhae298

Original Source URL

https://doi.org/10.1093/hr/uhae298

Funding information

This work was sponsored by the Key Research & Development Program of Ningxia Hui Autonomous Region (2022BBF01001 and 2021BEF02002), the National Natural Science Foundation of China (U23A20221), and the Innovative Research Group Project of Ningxia Hui Autonomous Region (No. 2021AAC01001).

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, 2023. 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.