Unlocking the secrets of color: The role of LhWRKY44 in enhancing anthocyanin accumulation in Asiatic hybrid lilies
image: Characterization of the LhWRKY44 transcription factor.
Credit: Horticulture Research
The Asiatic hybrid lily (Lilium spp.) is a horticultural crop with high commercial value and diverse anthocyanin pigmentation patterns. Anthocyanins not only determine the special color of plants, but also play a role in resisting environmental stress, aiding pollination, and scavenging reactive oxygen species. At present, the mechanism of anthocyanin biosynthesis and transport is relatively clear, but in monocots, particularly in lily, the role of WRKY transcription factors (TFs) in the regulatory mechanism underlying flower color is still largely unexplored.
In August 2023, Horticulture Research published a research entitled by “Multifaceted roles of LhWRKY44 in promoting anthocyanin accumulation in Asiatic hybrid lilies (Lilium spp.) ”. This paper reported the WRKY transcription factor from lily tepals, LhWRKY44, which is closely associated with anthocyanin accumulation.
Initially, through transcriptome data analysis and subsequent RT-qPCR, the expression pattern of LhWRKY44 was found to correlate with anthocyanin levels, particularly showing higher expression in basal tepals. Phylogenetic tree, subcellular localization and transcriptional activity analysis indicated that LhWRKY44 might work as a nucleus-localized transcriptional activator related to anthocyanin biosynthesis. Then, by transient silence and overexpression in lily, confirmed that LhWRKY44 positively regulated anthocyanin accumulation. The study also found that LhWRKY44 interacts with LhMYBSPLATTER and is directly bound to the LhMYBSPLATTER promoter, which enhanced the effect of the LhMYBSPLATTER-LhbHLH2 MBW complex activator on anthocyanin biosynthesis. Additionally, EMSA and dual-luciferase assays revealed that LhWRKY44 activated and bound to the promoters of LhF3H and glutathione S-transferase gene LhGST, indicating its involvement in both anthocyanin synthesis and transport.
The research further demonstrated LhWRKY44's role in light and drought-induced anthocyanin accumulation, and improved drought tolerance via activating stress-related genes. Overexpression of LhWRKY44 enhanced tolerance to drought stress in Arabidopsis. LhWRKY44 activated stress-related genes to enhance the drought tolerance of lily, and promoted anthocyanin accumulation. This dual role in environmental response and anthocyanin regulation suggests a complex regulatory mechanism where LhWRKY44 mediates anthocyanin accumulation in response to environmental cues.
In conclusion, this study significantly expands the understanding of WRKY-mediated transcriptional regulation in anthocyanin accumulation in Asiatic hybrid lilies. It highlights LhWRKY44's multifaceted role in anthocyanin biosynthesis and environmental stress response, offering insights into the genetic and molecular mechanisms underlying flower coloration and stress adaptation in lilies. The findings underscore the potential of manipulating WRKY transcription factors for horticultural improvement and stress resilience in plants.
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References
Authors
Mengmeng Bi1, Rui Liang1,2, Jiawen Wang1, Yuxiao Qu1, Xin Liu1,3, Yuwei Cao1,4, Guoren He1,5, Yue Yang1, Panpan Yang1, Leifeng Xu1,* and Jun Ming1,*
Affiliations
1State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
2College of Horticulture, Shanxi Agricultural University, Taigu, 030031, China
3College of Landscape architecture and Forestry, Qingdao Agricultural University, Qingdao, 266109, China
4College of Chemistry and Life Science, Gannan Normal University, Ganzhou, 341000, China
5Shanghai Key Laboratory of Plant Molecular Science, College of Life Sciences, Shanghai Normal University, Shanghai, 200233, China
About Jun Ming
He is a researcher at the Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences. and he is mainly engaged in lily resources and breeding, edible and medicinal function research. He is also an editorial board member of Acta Horticulturae Sinica、Subtropical Plant Science.