Methylation mediated by an anthocyanin, O-methyltransferase, is involved in purple flower coloration in Paeonia.

Autor:	Du H; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China., Wu J; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China University of Chinese Academy of Sciences, Beijing 100049, PR China., Ji KX; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China., Zeng QY; State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China., Bhuiya MW; MOgene Green Chemicals, Saint Louis, MO 63132, USA., Su S; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China University of Chinese Academy of Sciences, Beijing 100049, PR China., Shu QY; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China wanglsh@ibcas.ac.cn shuqy@ibcas.ac.cn., Ren HX; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China., Liu ZA; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China., Wang LS; Key Laboratory of Plant Resources/ Beijing Botanical Garden, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China wanglsh@ibcas.ac.cn shuqy@ibcas.ac.cn.
Jazyk:	angličtina
Zdroj:	Journal of experimental botany [J Exp Bot] 2015 Nov; Vol. 66 (21), pp. 6563-77. Date of Electronic Publication: 2015 Jul 23.
DOI:	10.1093/jxb/erv365
Abstrakt:	Anthocyanins are major pigments in plants. Methylation plays a role in the diversity and stability of anthocyanins. However, the contribution of anthocyanin methylation to flower coloration is still unclear. We identified two homologous anthocyanin O-methyltransferase (AOMT) genes from purple-flowered (PsAOMT) and red-flowered (PtAOMT) Paeonia plants, and we performed functional analyses of the two genes in vitro and in vivo. The critical amino acids for AOMT catalytic activity were studied by site-directed mutagenesis. We showed that the recombinant proteins, PsAOMT and PtAOMT, had identical substrate preferences towards anthocyanins. The methylation activity of PsAOMT was 60 times higher than that of PtAOMT in vitro. Interestingly, this vast difference in catalytic activity appeared to result from a single amino acid residue substitution at position 87 (arginine to leucine). There were significant differences between the 35S::PsAOMT transgenic tobacco and control flowers in relation to their chromatic parameters, which further confirmed the function of PsAOMT in vivo. The expression levels of the two homologous AOMT genes were consistent with anthocyanin accumulation in petals. We conclude that AOMTs are responsible for the methylation of cyanidin glycosides in Paeonia plants and play an important role in purple coloration in Paeonia spp. (© The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.)
Databáze:	MEDLINE
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