A team of researchers from the Institute of Vegetables and Flowers, Chinese Academy of Agricultural Science revealed a multifaceted regulatory mechanism for the LhWRKY44-mediated enhancement by the environmental signal pathway of anthocyanin accumulation

Anthocyanins are a group within the flavonoid family of plant secondary metabolites that determine the color of flowers and organs and protect plants from reactive oxygen species produced under environmental stresses. Spatially and temporally distinct deposition of anthocyanin accumulation in tepals of lilies produces multicolor and various colour patterning, including bicolor splatter-type spots, raised spots, and blush marks spot. Such as the Asiatic hybrid lilies Tango Series cultivars, in which anthocyanins are specifically colored in the basal tepals (referred to as splatter-type spots) and have special ornamental value. However, the underlying mechanism has not been well  explored.

This article has been published on Horticulture Research with title: Multifaceted roles of LhWRKY44 in promoting anthocyanin accumulation in Asiatic hybrid lilies (Lilium spp.)

Based on previous transcriptome data, we screened a WRKY TF LhWRKY44 from Asiatic hybrid Tango series lily cultivars, which was closely related to anthocyanin accumulation. In this study, we characterized the roles of the LhWRKY44 gene and elucidated the mechanism in which anthocyanin accumulation was regulated by LhWRKY44. LhWRKY44 physically interacted with LhMYBSPLATTER protein and directly bound to the LhMYBSPLATTER promoter, which enhanced the effect of the LhMYBSPLATTER-LhbHLH2 MBW complex activator on anthocyanin accumulation. Moreover, LhWRKY44 activated and bound to the promoters of the anthocyanin biosynthesis-related genes LhF3H and the intracellular anthocyanin-related glutathione S-transferase gene LhGST. Further results showed that LhWRKY44 participated in light and drought-induced anthocyanin accumulation, and improves the drought tolerance in lily by activating stress-related genes. Additionally, we accidentally noted that overexpression LhWRKY44 confers early flowering in transgenic Arabidopsis. Thus, LhWRKY44 might serve as a major regulator that integrated the environmental signal pathway and development signal pathway to determine the level and patterning of anthocyanin accumulation in Asiatic hybrid Tango series lily cultivars. Our findings indicated that multifaceted roles of LhWRKY44 in promoting anthocyanin accumulation in Asiatic hybrid lilies (Lilium spp.) and enrich the effects of the TF transcriptional regulation of anthocyanins.

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References

Authors

Mengmeng Bi, Rui Liang, Jiawen Wang, Yuxiao Qu, Xin Liu, Yuwei Cao, Guoren He, Yue Yang, Panpan Yang, Leifeng Xu, Jun Ming

Affiliations

State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China.

About Jun Ming

Jun Ming,  male, PhD, Doctoral supervisor. Lily resources and breeding expert. Editorial board member of 《Acta Horticulturae Sinica》、《Subtropical Plant Science》.