Journal Article

Functional study of CHS gene family members in citrus revealed a novel CHS gene affecting the production of flavonoids

Shen, Wanxia, El Mohtar, Choaa A., Wang, Zhibin, Gmitter, Fredrick G., Zhao, Xiaochun, Yu, Qibin

2018

Overview

Background Citrus flavonoids are considered as the important secondary metabolites because of their biological and pharmacological activities. Chalcone synthase (CHS) is a key enzyme that catalyses the first committed step in the flavonoid biosynthetic pathway. CHS genes have been isolated and characterized in many plants. Previous studies indicated that CHS is a gene superfamily. In citrus, the number of CHS members and their contribution to the production of flavonoids remains a mystery. In our previous study, the copies of CitCHS 2 gene were found in different citrus species and the sequences are highly conserved, but the flavonoid content varied significantly among those species. Results From seventy-seven CHS and CHS -like gene sequences, ten CHS members were selected as candidates according to the features of their sequences. Among these candidates, expression was detected from only three genes. A predicted CHS sequence was identified as a novel CHS gene. The structure analysis showed that the gene structure of this novel CHS is very similar to other CHS genes. All three CHS genes were highly conserved and had a basic structure that included one intron and two exons, although they had different expression patterns in different tissues and developmental stages. These genes also presented different sensitivities to methyl jasmonate (MeJA) treatment. In transgenic plants, the expression of CHS genes was significantly correlated with the production of flavonoids. The three CHS genes contributed differently to the production of flavonoids. Conclusion Our study indicated that CitCHS is a gene superfamily including at least three functional members. The expression levels of the CHS genes are highly correlated to the biosynthesis of flavonoids. The CHS enzyme is dynamically produced from several CHS genes, and the production of total flavonoids is regulated by the overall expression of CHS family genes.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Agriculture / biochemical pathways / Biomedical and Life Sciences / Biosynthesis / Cardiovascular disease / Cell culture / Chalcone synthase / CHS gene / CitCHS2 gene / Citrinae / Citrus / Citrus fruits / Cloning / Developmental stages / Enzymes / Exons / Flavonoid / Flavonoids / Fruits / Gene expression / Gene sequencing / Gene silencing / Genes / Genetic aspects / Genetics and crop biotechnology / Genomes / Identification and classification / introns / Life Sciences / medicinal properties / Metabolites / Methyl jasmonate / naringenin-chalcone synthase / Pathogens / Pharmacology / Phylogenetics / Physiological aspects / Plant genetics / Plant Sciences / Research Article / Secondary metabolites / Structural analysis / tissues / Transgenic plants / Tree Biology