LhGST is an anthocyanin-related glutathione S-transferase gene in Asiatic hybrid lilies (Lilium spp.)

Key message LhGST, an anthocyanin-related GST gene, was identified from Asiatic hybrid lilies. Expression and functional analyses demonstrated that LhGST might be involved in anthocyanin sequestration in lily tepals. Anthocyanins are responsible for the pink, red and purple pigmentation of flowers in Asiatic hybrid lilies, synthesized at the cytoplasmic surface of the endoplasmic reticulum (ER) and then transported to the vacuole. To date, the mechanism involved in the intracellular transport of anthocyanins in lilies has not been well elucidated. Here, full-length glutathione S-transferase gene (LhGST) was identified from lilies. Expression analysis revealed that LhGST was positively correlated with anthocyanin accumulation. Phylogenetic tree analysis showed that LhGST clustered with other anthocyanin-related GSTs in the same phi clade. Moreover, functional complementation of an Arabidopsis tt19 mutant demonstrated that LhGST might be involved in anthocyanin accumulation in lily tepals. Additionally, according to phenotype analysis, LhGST was found to be correlated with the transport of anthocyanin in lilies by virus-induced gene silencing (VIGS) assay. In addition, cis-element analysis of the LhGST promoter showed the presence of ABA-, auxin-, MeJA-, gibberellin-, light-, and stress-responsive elements and an MYB recognition site (MRS, CCGTTG). Yeast one-hybrid and dual-luciferase report assays revealed that the promoter of LhGST was activated by LhMYB12-lat, which is a key R2R3-MYB transcription factor that regulates anthocyanin biosynthesis in lilies. In conclusion, our results revealed that LhGST plays a key role in anthocyanin transport and accumulation in the tepals of lilies.

Automated summary

The study identified the LhGST gene in Asiatic hybrid lilies, which may be involved in anthocyanin sequestration and transport in lily tepals. Functional analysis confirmed the role of LhGST in anthocyanin accumulation. Additionally, the promoter of LhGST contains various hormone- and stress-responsive elements, and is regulated by a MYB transcription factor.