期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：22
页码：12328-12332
DOI：10.1073/pnas.96.22.12328
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Nuclear magnetic resonance (NMR) of isolated lignins from an Arabidopsis mutant deficient in ferulate 5-hydroxylase (F5H) and transgenic plants derived from the mutant by overexpressing the F5H gene has provided detailed insight into the compositional and structural differences between these lignins. Wild-type Arabidopsis has a guaiacyl-rich, syringyl-guaiacyl lignin typical of other dicots, with prominent {beta}-aryl ether ({beta}-O-4), phenylcoumaran ({beta}-5), resinol ({beta}-{beta}), biphenyl/dibenzodioxocin (5-5), and cinnamyl alcohol end-group structures. The lignin isolated from the F5H-deficient fah1-2 mutant contained only traces of syringyl units and consequently enhanced phenylcoumaran and dibenzodioxocin levels. In fah1-2 transgenics in which the F5H gene was overexpressed under the control of the cauliflower mosaic virus 35S promoter, a guaiacyl-rich, syringyl/guaiacyl lignin similar to the wild type was produced. In contrast, the isolated lignin from the fah1-2 transgenics in which F5H expression was driven by the cinnamate 4-hydroxylase promoter was almost entirely syringyl in nature. This simple lignin contained predominantly {beta}-aryl ether units, mainly with erythro-stereochemistry, with some resinol structures. No phenylcoumaran or dibenzodioxocin structures (which require guaiacyl units) were detectable. The overexpression of syringyl units in this transgenic resulted in a lignin with a higher syringyl content than that in any other plant we have seen reported.
