Cargando…

Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits

Proanthocyanidins (PAs) are distributed widely in Chinese bayberry fruit and have been associated with human health benefits, but molecular and biochemical characterization of PA biosynthesis remains unclear. Here, two genes encoding key PA biosynthetic enzymes, anthocyanidin reductase (ANR) and leu...

Descripción completa

Detalles Bibliográficos
Autores principales: Shi, Liyu, Cao, Shifeng, Chen, Xin, Chen, Wei, Zheng, Yonghua, Yang, Zhenfeng
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5835688/
https://www.ncbi.nlm.nih.gov/pubmed/29541082
http://dx.doi.org/10.3389/fpls.2018.00212
_version_ 1783303849801416704
author Shi, Liyu
Cao, Shifeng
Chen, Xin
Chen, Wei
Zheng, Yonghua
Yang, Zhenfeng
author_facet Shi, Liyu
Cao, Shifeng
Chen, Xin
Chen, Wei
Zheng, Yonghua
Yang, Zhenfeng
author_sort Shi, Liyu
collection PubMed
description Proanthocyanidins (PAs) are distributed widely in Chinese bayberry fruit and have been associated with human health benefits, but molecular and biochemical characterization of PA biosynthesis remains unclear. Here, two genes encoding key PA biosynthetic enzymes, anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) were isolated in bayberry fruit. MrANR was highly expressed at the early stage of fruit development when soluble PAs accumulated at high levels. Meanwhile, the transcript abundance of both MrANR and MrLAR observed at the late stage was paralleled with the high amounts of insoluble PAs. LC-MS/MS showed that PAs in developing Chinese bayberry fruits were comprised predominantly of epigallocatechin-3-O-gallate terminal subunits, while the extension subunits were a mixture of epigallocatechin-3-O-gallate, epigallocatechin and catechin. Recombinant MrANR protein converted cyanidin to a mixture of epicatechin and catechin, and delphinidin to a mixture of epigallocatechin and gallocatechin in vitro. Recombinant MrLAR was active with leucocyanidin as substrate to produce catechin. Ectopic expression of MrANR in tobacco reduced anthocyanin levels but increased PA accumulation. The catechin and epicatechin contents in transgenic flowers overexpressed MrANR were significantly higher than those of wild-type. However, overexpression of MrLAR in tobacco led to an increase in catechin levels but had no impact on PA contents. Quantitative real time PCR revealed that the loss of anthocyanin in transgenic flowers overexpressed MrANR or MrLAR is probably attributed to decreased expression of tobacco chalcone isomerase (CHI) gene. Our results not only reveal in vivo and in vitro functions for ANR and LAR but also provide a resource for understanding the mechanism of PA biosynthesis in Chinese bayberry fruit.
format Online
Article
Text
id pubmed-5835688
institution National Center for Biotechnology Information
language English
publishDate 2018
publisher Frontiers Media S.A.
record_format MEDLINE/PubMed
spelling pubmed-58356882018-03-14 Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits Shi, Liyu Cao, Shifeng Chen, Xin Chen, Wei Zheng, Yonghua Yang, Zhenfeng Front Plant Sci Plant Science Proanthocyanidins (PAs) are distributed widely in Chinese bayberry fruit and have been associated with human health benefits, but molecular and biochemical characterization of PA biosynthesis remains unclear. Here, two genes encoding key PA biosynthetic enzymes, anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) were isolated in bayberry fruit. MrANR was highly expressed at the early stage of fruit development when soluble PAs accumulated at high levels. Meanwhile, the transcript abundance of both MrANR and MrLAR observed at the late stage was paralleled with the high amounts of insoluble PAs. LC-MS/MS showed that PAs in developing Chinese bayberry fruits were comprised predominantly of epigallocatechin-3-O-gallate terminal subunits, while the extension subunits were a mixture of epigallocatechin-3-O-gallate, epigallocatechin and catechin. Recombinant MrANR protein converted cyanidin to a mixture of epicatechin and catechin, and delphinidin to a mixture of epigallocatechin and gallocatechin in vitro. Recombinant MrLAR was active with leucocyanidin as substrate to produce catechin. Ectopic expression of MrANR in tobacco reduced anthocyanin levels but increased PA accumulation. The catechin and epicatechin contents in transgenic flowers overexpressed MrANR were significantly higher than those of wild-type. However, overexpression of MrLAR in tobacco led to an increase in catechin levels but had no impact on PA contents. Quantitative real time PCR revealed that the loss of anthocyanin in transgenic flowers overexpressed MrANR or MrLAR is probably attributed to decreased expression of tobacco chalcone isomerase (CHI) gene. Our results not only reveal in vivo and in vitro functions for ANR and LAR but also provide a resource for understanding the mechanism of PA biosynthesis in Chinese bayberry fruit. Frontiers Media S.A. 2018-02-28 /pmc/articles/PMC5835688/ /pubmed/29541082 http://dx.doi.org/10.3389/fpls.2018.00212 Text en Copyright © 2018 Shi, Cao, Chen, Chen, Zheng and Yang. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Plant Science
Shi, Liyu
Cao, Shifeng
Chen, Xin
Chen, Wei
Zheng, Yonghua
Yang, Zhenfeng
Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits
title Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits
title_full Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits
title_fullStr Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits
title_full_unstemmed Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits
title_short Proanthocyanidin Synthesis in Chinese Bayberry (Myrica rubra Sieb. et Zucc.) Fruits
title_sort proanthocyanidin synthesis in chinese bayberry (myrica rubra sieb. et zucc.) fruits
topic Plant Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5835688/
https://www.ncbi.nlm.nih.gov/pubmed/29541082
http://dx.doi.org/10.3389/fpls.2018.00212
work_keys_str_mv AT shiliyu proanthocyanidinsynthesisinchinesebayberrymyricarubrasiebetzuccfruits
AT caoshifeng proanthocyanidinsynthesisinchinesebayberrymyricarubrasiebetzuccfruits
AT chenxin proanthocyanidinsynthesisinchinesebayberrymyricarubrasiebetzuccfruits
AT chenwei proanthocyanidinsynthesisinchinesebayberrymyricarubrasiebetzuccfruits
AT zhengyonghua proanthocyanidinsynthesisinchinesebayberrymyricarubrasiebetzuccfruits
AT yangzhenfeng proanthocyanidinsynthesisinchinesebayberrymyricarubrasiebetzuccfruits