Comparative gene expression analysis in a highly anthocyanin pigmented mutant of colorless chrysanthemum

Abstract

In this study, we investigated differentially expressed genes between the original chrysanthemum cultivar 'Argus' with white flower color and its gamma-ray irradiated mutant 'ARTI-purple' with purple flower color. The expression levels of anthocyanin biosynthetic genes were not associated with anthocyanin accumulations of Argus and ARTI-purple. Expressed sequence tags (ESTs) analysis was performed to identify a novel cDNAs encoding enzymes of specific plant metabolic pathways and the biological effects of gamma-ray mutation through alterations in expression in each flower. A total of 796 unigenes were isolated from chrysanthemum ray florets. These unigenes were functionally classified using gene ontologies and tentative pathway associations were established to 99 sequences in the Kyoto encyclopedia of genes and genomes. The expressions of the isolated ESTs were screened by cDNA dot blot hybridization. Seven differentially expressed genes were identified as being involved in carbohydrate and lipid metabolic pathways and five as transcription factor or signal transduction genes. Of particular note, decreased expression of CmMYB1 was identified at the 'ARTI-purple'. The CmMYB1 shared high similarity with AtMYB4 and AtMYBL2 which is a negative regulator of anthocyanin and flavonol accumulation. Furthermore, two genes involved in lipid metabolism, enoyl-ACP reductase and [acyl-carrier-protein] S-malonyltransferase, were decreased in the 'ARTI-purple' flower. Our results suggest that the purple pigmentation of the 'ARTI-purple' is not just dependent on the expression of anthocyanin synthesis genes, and that the pigmentation may also affect other metabolic processing and the plant cell environment.

MYB transcription factor isolated from Raphanus sativus enhances anthocyanin accumulation in chrysanthemum cultivars

“…However, analysis of anthocyanin content using a spectrophotometer revealed that anthocyanin contents in transgenic lines of the cultivars were significantly higher than those in the controls. Thus, anthocyanin accumulation in the cultivars was correlated with the expression pattern of biosynthetic genes as reported by the researchers (Chen et al 2012 ; He et al 2013 ; Sung et al 2013 ), but anthocyanin content produced by RsMYB1 seemed to be genotype-dependent because enhancement of anthocyanin contents in cultivars ‘Peach ND’ and ‘Vivid Scarlet’ seemed to be higher than that in cultivar ‘Peach Red’ (Fig. 5 ).…”

“…In addition, many researchers have documented that anthocyanin accumulation in chrysanthemum correlated with the expression pattern of biosynthetic genes (Chen et al 2012 ; He et al 2013 ; Sung et al 2013 ). Since the main anthocyanin biosynthesis pathway in chrysanthemum is the cyanidin-based pathway (He et al 2013 ), CHS , CHI , F3H , DFR , and ANS are considered as five key biosynthetic genes responsible for anthocyanin accumulation in chrysanthemum.…”

“…Absorbance was measured at 430–630 nm by using a spectrophotometer (U-2800; Hitachi, Tokyo, Japan). Anthocyanin content of each sample was calculated according to the method reported by Sung et al ( 2013 ).…”

Molecular mechanisms underlying the diverse array of petal colors in chrysanthemum flowers

“…In the white-flowered mutant lines, reduced expression of genes encoding either enzymes or positive regulators of anthocyanin biosynthesis were observed ( Han et al 2012 ). In the purplish-red-flowered mutant lines, expression of a R2R3-MYB transcription factor (designated CmMYB1) was markedly reduced ( Sung et al 2013 ). Because the amino acid sequence of CmMYB1 showed high similarity to AtMYB4, which are negative regulators of anthocyanin biosynthesis in Arabidopsis ( Jin et al 2000 , Matsui et al 2008 ), the authors suggested that CmMYB1 also acts as a negative regulator of anthocyanin biosynthesis in chrysanthemum ray petals.…”

Chrysanthemum biotechnology: discoveries from the recent literature

“…Using a purple gamma-ray irradiated mutant 'ARTIpurple', and analyzing expressed sequence tags (ESTs), Sung et al (2013) identified novel cDNAs encoding enzymes of specific plant metabolic pathways that reflect the unique expression caused by gamma-ray mutation -invariably one of the most popular breeding methods. They isolated 796 unigenes from ray florets, some of which were involved in carbohydrate and lipid metabolic pathways, or were transcription factors or signal transduction genes.…”