Proanthocyanidin synthesis in Theobroma cacao: genes encoding anthocyanidin synthase, anthocyanidin reductase, and leucoanthocyanidin reductase

BMC Plant Biology

Research Article

Siela Maximova¹  Mark J Guiltinan¹  Mark J Payne²  Zi Shi³  Yi Liu⁴ 

[1] Department of Plant Science, The Pennsylvania State University, 422 Life Sciences Building, 16802, University Park, PA, USA;Hershey Center for Health and Nutrition, The Hershey Company, 1025 Reese Ave, 17033, Hershey, PA, USA;Huck Institute of Life Sciences, The Pennsylvania State University, 16802, University Park, PA, USA;Huck Institute of Life Sciences, The Pennsylvania State University, 16802, University Park, PA, USA;Cellular & Molecular Pharmacology, Mission Bay Campus, Genentech Hall, University of California, N582/Box 2280, 600 16th Street, 94158, San Francisco, CA, USA;

关键词: Bacterial Artificial Chromosome;    Catechin;    Bacterial Artificial Chromosome Clone;    Epicatechin;    Cetyl Trimethyl Ammonium Bromide;   

DOI  :  10.1186/1471-2229-13-202

 received in 2013-07-22, accepted in 2013-11-29,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundThe proanthocyanidins (PAs), a subgroup of flavonoids, accumulate to levels of approximately 10% total dry weight of cacao seeds. PAs have been associated with human health benefits and also play important roles in pest and disease defense throughout the plant.ResultsTo dissect the genetic basis of PA biosynthetic pathway in cacao (Theobroma cacao), we have isolated three genes encoding key PA synthesis enzymes, anthocyanidin synthase (ANS), anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR). We measured the expression levels of TcANR, TcANS and TcLAR and PA content in cacao leaves, flowers, pod exocarp and seeds. In all tissues examined, all three genes were abundantly expressed and well correlated with PA accumulation levels, suggesting their active roles in PA synthesis. Overexpression of TcANR in an Arabidopsis ban mutant complemented the PA deficient phenotype in seeds and resulted in reduced anthocyanidin levels in hypocotyls. Overexpression of TcANS in tobacco resulted in increased content of both anthocyanidins and PAs in flower petals. Overexpression of TcANS in an Arabidopsis ldox mutant complemented its PA deficient phenotype in seeds. Recombinant TcLAR protein converted leucoanthocyanidin to catechin in vitro. Transgenic tobacco overexpressing TcLAR had decreased amounts of anthocyanidins and increased PAs. Overexpressing TcLAR in Arabidopsis ldox mutant also resulted in elevated synthesis of not only catechin but also epicatechin.ConclusionOur results confirm the in vivo function of cacao ANS and ANR predicted based on sequence homology to previously characterized enzymes from other species. In addition, our results provide a clear functional analysis of a LAR gene in vivo.

【 授权许可】

Unknown   
© Liu et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.