Physiological and Genomic Analysis Reveals Candidate Genes Involved in Anthocyanin Biosynthesis in Colored-leaf Poplar ‘Caihong’ (Populus deltoides)

Leaf color is an important
agronomic trait that contributes to the ornamental value of plants. However, the
molecular mechanism of leaf coloration is still unclear. In our study, a
colored-leaf poplar ‘Caihong’ (CHP, bright red leaves) and wild-type L2025
(green leaves) were used to explore the mechanism of leaf coloration by
physiological and genomic analysis. Compared with leaves of L2025, leaves of
CHP had a higher content of anthocyanins and a lower content of total Chl and
carotenoids, and the ratio of anthocyanins to total Chl in CHP was more than 10
times of those in L2025, which may be the physiological reason why they show
red leaf color. Based on the whole genome resequencing and bioinformatics
analysis, eight structural genes and 20 regulatory genes associated with
anthocyanin biosynthesis carrying more than five non-synonymous SNPs in coding
regions were screened. These candidate genes were also identified according to
the qRT-PCR analysis, and eight structural genes and three MYB family genes
might play important roles in the leaf coloration of CHP. The above results
could provide reference to explore the molecular regulation mechanism of leaf
coloration in <i>Populus deltoids</i>, and
also provided insight into coloration of other woody plants.