AUTHOR=He Chunmei , Wu Kunlin , Zhang Jianxia , Liu Xuncheng , Zeng Songjun , Yu Zhenming , Zhang Xinghua , Teixeira da Silva Jaime A. , Deng Rufang , Tan Jianwen , Luo Jianping , Duan Jun 

TITLE=Cytochemical Localization of Polysaccharides in Dendrobium officinale and the Involvement of DoCSLA6 in the Synthesis of Mannan Polysaccharides

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 8 - 2017

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00173

DOI=10.3389/fpls.2017.00173

ISSN=1664-462X

ABSTRACT=<p><italic>Dendrobium officinale</italic> is a precious traditional Chinese medicinal plant because of its abundant polysaccharides found in stems. We determined the composition of water-soluble polysaccharides and starch content in <italic>D</italic>. <italic>officinale</italic> stems. The extracted water-soluble polysaccharide content was as high as 35% (w/w). Analysis of the composition of monosaccharides showed that the water-soluble polysaccharides were dominated by mannose, to a lesser extent glucose, and a small amount of galactose, in a molar ratio of 223:48:1. Although starch was also found, its content was less than 10%. This result indicated that the major polysaccharides in <italic>D</italic>. <italic>officinale</italic> stems were non-starch polysaccharides, which might be mannan polysaccharides. The polysaccharides formed granules and were stored in plastids similar to starch grains, were localized in <italic>D</italic>. <italic>officinale</italic> stems by semi-thin and ultrathin sections. <italic>CELLULOSE SYNTHASE-LIKE A</italic> (<italic>CSLA</italic>) family members encode mannan synthases that catalyze the formation of mannan polysaccharides. To determine whether the <italic>CSLA</italic> gene from <italic>D</italic>. <italic>officinale</italic> was responsible for the synthesis of mannan polysaccharides, <italic>35S</italic>:<italic>DoCSLA6</italic> transgenic lines were generated and characterized. Our results suggest that the <italic>CSLA</italic> family genes from <italic>D. officinale</italic> play an important role in the biosynthesis of mannan polysaccharides.</p>