Ph5GT silencing alters flower color and flavonoids metabolome profile in petunia

Abstract

Anthocyanins are important pigments in plants and glycosylation plays an important role in the stability of anthocyanins. Anthocyanin 5‐O‐glucosyltransferase (5GT) can glycosylate anthocyanin at the 5‐O‐position. Till now, the enzymatic activity characteristics of 5GT had been studied in vitro in a variety of plants. However, the subcellular localization of 5GT protein still remained unclear, and little genetic evidence on the roles of 5GT in plants has been reported. The full‐length Ph5GT gene from petunia (Petunia hybrida) was isolated in this study. Green fluorescent fusion protein assays revealed that Ph5GT protein was localized to the cytoplasm. Ph5GT was found to be highly expressed in flowers, with highest levels of expression occurring during the coloring stage of flower development. Furthermore, Ph5GT silencing led to the change in flower color from purple to light purple and a significant reduction in total anthocyanin content. The metabolome analysis revealed that the content of malvidins and petunidins modified by glycosylation at the 5‐O‐position was significantly reduced, while the content of their precursor without glycosylation was significantly increased, implying that Ph5GT could glycosylate malvidin and petunidin derivatives and that the substrate types of Ph5GT were expanded in comparison to previous studies.

PhAAT1, encoding an anthocyanin acyltransferase, is transcriptionally regulated byPhAN2in petunia

“…The expression profile of PhAAT1 in the corollas was similar to petunia UDP-rhamnose: anthocyanin 3-glucoside rhamonosyltransferase, PhAT48 and Ph5GT (X. Li et al, 2022;Yonekura-Sakakibara et al, 2000). Similarly, the mRNA levels of Ph3GT and Ph5GT, which are responsible for anthocyanin glycosylation, gradually increased during the early stages of flower development and peaked before the blooming stage in petunia (Yamazaki et al, 2002).…”

Plant volatiles and color compounds: From biosynthesis to function

“…After integrating the data with multivariate analysis, key terpene synthase genes involved in fruit and flower aroma biosynthesis were discovered. has a major impact on anthocyanin contents in petunia flowers, and that suppressing the aforementioned gene changed the color of the petunia from purple to light purple (Li et al, 2022). Furthermore, metabolic findings indicate that glycosylation significantly altered the 5-Oposition of petunidins and malvidins.…”

“…The authors mentioned that PhAAT1 was strongly regulated by MYB TFs (PhAN2) and that silencing PhAAT1 lowered anthocyanin stability and modified color by reducing caffeoylated and p‐coumaroylated anthocyanins, and PhAAT1 protein was located in the cytoplasm. Another study found that 5‐O‐glucosyltransferase (5GT) has a major impact on anthocyanin contents in petunia flowers, and that suppressing the aforementioned gene changed the color of the petunia from purple to light purple (Li et al, 2022). Furthermore, metabolic findings indicate that glycosylation significantly altered the 5‐O‐position of petunidins and malvidins.…”