Inheritance, gene expression, and lignin characterization in a mutant pine deficient in cinnamyl alcohol dehydrogenase
Inheritance, gene expression, and lignin characterization in a mutant pine deficient in cinnamyl alcohol dehydrogenase
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DOI：
10.1073/pnas.94.15.8255
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发表时间：
1997-07-22
影响因子：
11.1
通讯作者：
Sederoff, RR
中科院分区：
文献类型：
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作者：
MacKay, JJ;OMalley, DM;Sederoff, RR
我们发现了一种突变体山毛松（Pinus taeda L.），其中编码肉桂醇脱氢酶（CAD; EC 1.1.1.195）的基因表达严重降低，CAD的产物肉桂醇是木质素的前体，木质素是植物维管组织的主要细胞壁聚合物，在该突变体中木质素的组成发生了巨大的变化，包括CAD底物（松木醛）的增加，表明CAD可能调节了松树的木质素组成。引起该表型的隐性CAD -n1等位基因是在该突变等位基因的树杂合中发现的，它作为一个简单的孟德尔位点遗传，与末端位点位于相同的基因组区域，在突变植物中，CAD活性和末端RNA转录物的丰度较低，游离CAD底物积累水平较高，突变型木材呈棕色，而野生型木材接近白色。木材表型类似于棕色中脉（bm）突变体和一些由于CAD活性降低而木质部呈红棕色的转基因植物，然而，与CAD降低的转基因植物不同，松树突变体木质素含量降低，木质素组成变化超出先前预期的木材仍然提供维管功能和机械支持。
We have discovered a mutant loblolly pine (Pinus taeda L.) in which expression of the gene encoding cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) is severely reduced, The products of CAD, cinnamyl alcohols, are the precursors of lignin, a major cell wall polymer of plant vascular tissues, Lignin composition in this mutant shows dramatic modifications, including increased incorporation of the substrate of CAD (coniferaldehyde), indicating that CAD may modulate lignin composition in pine. The recessive cad-n1 allele, which causes this phenotype, was discovered in a tree heterozygous for this mutant allele, It is inherited as a simple Mendelian locus that maps to the same genomic region as the end locus, In mutant plants, CAD activity and abundance of end RNA transcript are low, and free CAD substrate accumulates to a high level, The wood of the mutant is brown, whereas the wood in wild types is nearly white, The wood phenotype resembles that of brown midrib (bm) mutants and some transgenic plants in which xylem is red-brown due to a reduction in CAD activity, However, unlike transgenics with reduced CAD, the pine mutant has decreased lignin content, Wood in which the composition of lignin varies beyond previous expectations still provides vascular function and mechanical support.