Metabolome analysis reveals flavonoid changes during the leaf color transition in Populus × euramericana ‘Zhonghuahongye’

Abstract

IntroductionTo investigate the mechanism of leaf color change at different stages in Populus × euramericana ‘Zhonghuahongye’ (‘Zhonghong’ poplar).MethodsLeaf color phenotypes were determined and a metabolomic analysis was performed on leaves at three stages (R1, R2 and R3).ResultsThe a*, C* and chromatic light values of the leaves decreased by 108.91%, 52.08% and 113.34%, while the brightness L values and chromatic b* values gradually increased by 36.01% and 13.94%, respectively. In the differential metabolite assay, 81 differentially expressed metabolites were detected in the R1 vs. R3 comparison, 45 were detected in the R1 vs. R2 comparison, and 75 were detected in the R2 vs. R3 comparison. Ten metabolites showed significant differences in all comparisons, which were mostly flavonoid metabolites. The metabolites that were upregulated in the three periods were cyanidin 3,5-O-diglucoside, delphinidin, and gallocatechin, with flavonoid metabolites accounting for the largest proportion and malvidin 3- O-galactoside as the primary downregulated metabolite. The color shift of red leaves from a bright purplish red to a brownish green was associated with the downregulation of malvidin 3-O-glucoside, cyanidin, naringenin, and dihydromyricetin.DiscussionHere, we analyzed the expression of flavonoid metabolites in the leaves of ‘Zhonghong’ poplar at three stages and identified key metabolites closely related to leaf color change, providing an important genetic basis for the genetic improvement of this cultivar.

Metabolome combined with transcriptome profiling reveals the dynamic changes in flavonoids in red and green leaves of Populus × euramericana ‘Zhonghuahongye’

“…More than 100 compounds have been isolated from Populus nigra extract, including phenolic compounds, terpenoids, flavonoids, flavanone, caffeic and p-coumaric acids, and nearly 50 molecules from the essential oil of its buds ( Tebbi & Debbache-Benaida, 2022 ). To date, several studies have focused on the chemical composition of Populus red leaves ( Tian et al., 2021 ; Chen et al., 2023 ), whereas no further analysis has been conducted on the difference in the composition between red and green leaves throughout the lifecycle. In this study, we profiled the flavonoid compositions of the red and green leaves of Populus × euramericana ‘Zhonghuahongye’ at three stages.…”

“…In Chen’s study, at three stages of leaf development (R1, R2, and R3) of Populus × euramericana ‘Zhonghuahongye’, 81 differentially abundant metabolites were detected in the R1 vs. R3 comparison, 45 were detected in the R1 vs. R2 comparison, and 75 were detected in the R2 vs. R3 comparison. Ten metabolites showed significant differences in all comparisons, which were mostly flavonoid metabolites ( Chen et al., 2023 ). Unlike previous reports, our study observed leaves from the tender stage to the mature stage of Populus × euramericana ‘Zhonghuahongye’.…”

“…The c olor of Populus × e u ra m er ic an a 'Zhonghuahongye' leaves varies from bright red to reddish brown with age. Flavonoid and anthocyanin metabolites are differentially expressed as the color changes (Chen et al, 2023). Another study showed that in Populus deltoides varieties with red leaves, the contents of quercetin, rhamnetin, isorhamnetin, and kaempferol were higher than those in the green leaves of Populus sp.…”

Changes in Photosynthetic Characteristics between Green-Leaf Poplar Linn. “2025” and Its Bud-Sporting Colored-Leaf Cultivars

“…However, its further popularization and application are limited due to its single leaf color. In recent years, many kinds of coloredleaf poplars with splendid ornamental values, such as 'Zhonghong poplar' (ZHP) [3], 'Quanhong poplar' (QHP) [4], and 'Caihong poplar' (CHP) [5], have been bred from the bud sport of L2025. They are very suitable for urban, garden, and road beautification and bring great economic, social, and ecological benefits [5,6].…”

Comparative Transcriptome and Metabolome Profiling Reveal Mechanisms of Red Leaf Color Fading in Populus × euramericana cv. ‘Zhonghuahongye’

“…Previous studies on leaf color changes in 'Zhonghuahongye' have primarily focused on leaf pigment changes and metabolite changes [10]. Although metabonomic studies for flavonoids have been conducted using 'Zhonghuahongye' [11], there has been limited research focusing on flavonoid biosynthesis. Additionally, the molecular mechanism of flavonoid accumulation and biosynthesis in 'Zhonghuahongye' remains largely unexplored.…”