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Characterization of Proanthocyanidins as a Biomarker for Wood Quality in the Native Timber-Wood Tree Acacia koa.

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Title:Characterization of Proanthocyanidins as a Biomarker for Wood Quality in the Native Timber-Wood Tree Acacia koa.
Authors:Corpuz, Maia L.
Contributors:Molecular Biosciences & Bioeng (department)
Keywords:Acacia koa
wood quality
wood color
Date Issued:Aug 2017
Publisher:University of Hawaiʻi at Mānoa
Abstract:Acacia koa (koa) is an economically valuable timber wood tree playing an important
role for Hawaiian culture and ecology. Wood color of koa can range from blond to dark
red while its grain figure ranges from plain to curly. Given that koa populations are
highly heterozygous and heterogeneous due to cross-pollinating nature, there is no
current screening method to select seedlings for superior wood quality.
Proanthocyanidins (PA), a subclass of tannins, are shown to be involved in wood
quality. The goal of this study was to quantify PAs and identify PA biosynthesis genes
as a biomarker for wood color. PA biosynthesis genes in koa were identified and
isolated including dihydroflavonol reductase, anthocyanidin synthase, anthocyanidin
reductase, and leucoanthocyanidin reductase. To correlate wood color, PAs, and
expression of PA biosynthesis genes, koa seedlings expressing green to red hues were
compared from Hawai‘i, O‘ahu, Kaua‘i, and Maui. Measurement of total tannin content
was analyzed by the Folin-Ciocalteau method and PA content was measured by acid
butanol assay in dry matter. Red-hued koa from Maui contained the highest total tannin
and PA content. Distribution of the total tannin and PA content was assessed within koa
seedlings expressing either green or red hues (O‘ahu and Maui). Total tannin content
varied significantly among tissue type (leaf, stem, root). Aside from PA content also
varying among tissue type, an opposing trend of lowest to highest PA content
dependent on the hue expression of the family was observed. This suggests PA content
is correlated to the overall hue of each family. qRT-PCR analysis of PA biosynthesis
gene expression showed an upregulation in red-hued koa (Maui) compared to greenhued
koa (Hawai‘i and O‘ahu). This suggests PA biosynthesis gene expression is also
correlated to the overall hue of each family. Liquid chromatography-mass spectrometry
(LC-MS) confirmed procyanidin B2 as the type of proanthocyanidin in koa.
Characterizing proanthocyanidins as a biomarker for wood quality will be useful as a
rapid screening method among progenies of different families in koa improvement
Description:M.S. Thesis. University of Hawaiʻi at Mānoa 2017.
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: M.S. - Molecular Biosciences and Bioengineering

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