Systematic analysis of O -methyltransferase gene family and identification of potential members involved in the formation of O -methylated flavonoids in Citrus

Liu, Xiaogang; Luo, Yan; Wu, Hongkun; Xi, Wanpeng; Li, Jingling; Zhang, Qiuyun; Zhou, Zhiqin

doi:10.1016/j.gene.2015.09.048

Cited by 49 publications

(45 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In citrus, it was reported that 58 OMT genes existed and were unevenly distributed on the nine chromosomes of Citrus sinensis. Among them, 27 OMTs were predicted to be involved in the O-methylation of flavonoids from the DGE and qRT-PCR analysis 45 . To date, two OMTs, CdFOMT5 and CrOMT1, have been isolated and their functions were characterized in citrus fruit.…”

Section: Discussionmentioning

confidence: 99%

Expression and functional analysis of the nobiletin biosynthesis-related gene CitOMT in citrus fruit

Seoka

Zhang

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Nobiletin, a polymethoxy flavone (PMF), is specific to citrus and has been reported to exhibit important health-supporting properties. Nobiletin has six methoxy groups at the 3′,4′,5,6,7,8-positions, which are catalyzed by O-methyltransferases (OMTs). To date, researches on OMTs in citrus fruit are still limited. In the present study, a novel OMT gene (CitOMT) was isolated from two citrus varieties Satsuma mandarin (Citrus unshiu Marc.) and Ponkan mandarin (Citrus reticulata Blanco), and its function was characterized in vitro. The results showed that the expression of CitOMT in the flavedo of Ponkan mandarin was much higher than that of Satsuma mandarin during maturation, which was consistent with the higher accumulation of nobiletin in Ponkan mandarin. In addition, functional analysis showed that the recombinant protein of CitOMT had methylation activity to transfer a methyl group to 3′-hydroxy group of flavones in vitro. Because methylation at the 3′-position of flavones is vital for the nobiletin biosynthesis, CitOMT may be a key gene responsible for nobiletin biosynthesis in citrus fruit. The results presented in this study will provide new strategies to enhance nobiletin accumulation and improve the nutritional qualities of citrus fruit.

show abstract

Section: Discussionmentioning

confidence: 99%

Expression and functional analysis of the nobiletin biosynthesis-related gene CitOMT in citrus fruit

Seoka

Zhang

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…In silico analysis of the OMT family has been comprehensively performed in Citrus sinensis, and candidate genes for flavonoid O-methylation have been predicted based on the phylogenetic tree [24]. CdFOMT5 from Citrus depressa has been demonstrated to be a multifunctional OMT and can methylate the 3-, 5-, 6-, and 7-OH of flavones by in vitro experiment [25].…”

Section: Introductionmentioning

confidence: 99%

Characterization of a Flavonoid 3’/5’/7-O-Methyltransferase from Citrus reticulata and Evaluation of the In Vitro Cytotoxicity of Its Methylated Products

et al. 2020

View full text Add to dashboard Cite

O-methylation of flavonoids is an important modification reaction that occurs in plants. O-methylation contributes to the structural diversity of flavonoids, which have several biological and pharmacological functions. In this study, an O-methyltransferase gene (CrOMT2) was isolated from the fruit peel of Citrus reticulata, which encoding a multifunctional O-methyltransferase and could effectively catalyze the methylation of 3’-, 5’-, and 7-OH of flavonoids with vicinal hydroxyl substitutions. Substrate preference assays indicated that this recombinant enzyme favored polymethoxylated flavones (PMF)-type substrates in vitro, thereby providing biochemical evidence for the potential role of the enzyme in plants. Additionally, the cytotoxicity of the methylated products from the enzymatic catalytic reaction was evaluated in vitro using human gastric cell lines SGC-7901 and BGC-823. The results showed that the in vitro cytotoxicity of the flavonoids with the unsaturated C2-C3 bond was increased after being methylated at position 3’. These combined results provide biochemical insight regarding CrOMT2 in vitro and indicate the in vitro cytotoxicity of the products methylated by its catalytic reaction.

show abstract

“…CCoAOMTs and CCoAOMT-like enzymes form a family within O -methyltransferases characterized by molecular weight ranging between 26 and 29 kDa and divalent metal ions in the active site (Ferrer et al 2005 ; Joshi and Chiang 1998 ; Lee et al 2008 ; Liu et al 2016 ; Walker et al 2016 ; Widiez et al 2011 ). Despite the similarities, CCoAOMTs are substrate specific and use two methyl acceptors, caffeoyl-coenzyme A or 5-hydroxyferuloyl-coenzyme A, but CCoAOMT-like enzymes use a variety of compounds, including flavonoids, anthocyanins, phenylpropanoids or alkaloids (Ibdah et al 2003 ; Inoue et al 1998 ; Widiez et al 2011 ).…”

Section: Introductionmentioning

confidence: 99%

Sorghum CCoAOMT and CCoAOMT-like gene evolution, structure, expression and the role of conserved amino acids in protein activity

et al. 2018

View full text Add to dashboard Cite

Sorghum is a crop plant that is grown for seeds, sucrose, forage and biofuel production. In all these applications, lignin is a superfluous component that decreases the efficiency of technological processes. Caffeoyl-coenzyme A O-methyltransferase (CCoAOMT) is an enzyme involved in monolignol synthesis that affects the efficiency of lignification and lignin composition. The sorghum genome harbors one CCoAOMT gene and six closely related CCoAOMT-like genes. The structures of four sorghum CCoAOMT-like enzymes suggest that these proteins might methylate caffeoyl coenzyme A and contribute to monolignol synthesis. In this study, two sorghum genes, CCoAOMT and one CCoAOMT-like, were found to be highly expressed in leaves, stems and immature seeds. The promoters of these genes possess clusters of transcription factor-binding sites specific for lignification, and this suggests that they are important for lignification. Phylogenetic analysis revealed that one sorghum CCoAOMT-like enzyme is closely related to ancestral cyanobacterial CCoAOMT-like proteins. The remaining CCoAOMT-like enzymes, including the one highly expressed in the leaves and stem, are closely related to CCoAOMT. Genes from these two groups possess different, evolutionarily conserved gene structures. The structure of the sorghum CCoAOMT-like protein from the ancestral clade was modeled and differences between enzymes from the two clades were analyzed. These results facilitate a better understanding of the evolution of genes involved in lignification, and provide valuable data for sorghum improvement through traditional breeding or molecular genetic techniques. The findings suggest that CCoAOMT-like genes might be recruited in lignification and raise questions of the frequency of such functional shifts.Electronic supplementary materialThe online version of this article (10.1007/s00438-018-1441-6) contains supplementary material, which is available to authorized users.

show abstract

Systematic analysis of O -methyltransferase gene family and identification of potential members involved in the formation of O -methylated flavonoids in Citrus

Cited by 49 publications

References 69 publications

Expression and functional analysis of the nobiletin biosynthesis-related gene CitOMT in citrus fruit

Expression and functional analysis of the nobiletin biosynthesis-related gene CitOMT in citrus fruit

Characterization of a Flavonoid 3’/5’/7-O-Methyltransferase from Citrus reticulata and Evaluation of the In Vitro Cytotoxicity of Its Methylated Products

Sorghum CCoAOMT and CCoAOMT-like gene evolution, structure, expression and the role of conserved amino acids in protein activity

Contact Info

Product

Resources

About