Molecular mechanisms for the biosynthesis of heartwood substances

心材是游离树干内部的有色区域，它的形成是木本植物特有的代谢事件，因为它不在草本植物中运行。近年来，树木代谢工程得到了长足的发展。例如，Chiang和他的同事已经成功地生产出了木素含量较少、纤维素含量较高的转基因杨木。等人，1999；Li等人。等人，2003年)。这些进展是在草本植物分子生物学知识的帮助下实现的。现在，有必要利用木本植物特有的代谢事件的分子机制来加速树木的代谢工程。尽管对分子机制一无所知，但木脂素、去甲木脂素及其相关化合物的生物合成参与心材形成的事实表明，它们生物合成的分子机制可以为我们阐明心材形成…提供线索。更多的机制.自1990年以来，Umezawa，et.艾尔报道了第一个从无手性松柏醇(Umezawa et.)艾尔关于合成木脂素的酶(Umezawa，2001；Umezawa，2003；Umezawa，2005；Suzuki和Umezawa，2007)。此外，还检测到去甲木素合成酶活性(Suzuki，et.Al.，2002)。在本项目中，作为前人工作的延续，主要研究者(Umezawa)和同事们研究了木脂素和去甲木脂素的生物合成机制。因此，他们首先建立了一套全面定量分析木脂素、去甲木脂素和木质素前体的肉桂酸/单醇醇途径化合物的系统。然后对木脂素生物合成和去甲木脂素生物合成的分子机制进行了研究。此外，还对木脂素、去甲木脂素和木质素生物合成的上游步骤--肉桂酸/单醇醇途径的一些酶的编码基因进行了分析。较少

Heartwood is the colored region of the inner part of free trunks, and its formation is a metabolic event specific to woody plants, as it does not operate in herbaceous plants. Recently, metabolic engineering of trees has been developed significantly. For example, a transgenic aspen (Populus tremuloides) with less lignin and higher cellulose contents has been successfully produced by Chiang and co-workers (Hu, et. al., 1999 ; Li, et. al., 2003). These developments were achieved with the aid of the knowledge of herbaceous plant molecular biology. Now, it is necessary to exploit knowledge of molecular mechanisms for metabolic events specific to woody plants in order to accelerate metabolic engineering of trees. Although nothing is known about the molecular mechanisms, the facts that biosynthesis of lignans, norlignans and related compounds are involved in heartwood formation implies that the molecular mechanisms of their biosynthesis can be a clue to help us elucidate heartwood formation … More mechanisms.Since in 1990 Umezawa, et. al. reported the first enzymatic reaction producing an optically pure lignan from achiral coniferyl alcohol (Umezawa, et. al. 1990), much has been learned about the enzymes synthesizing lignans (Umezawa, 2001 ; Umezawa, 2003 ; Umezawa, 2005 ; Suzuki and Umezawa, 2007). In addition, a norlignan synthase activitie has been detected (Suzuki, et. al., 2002). In the present project as the continuation of the previous works, the principal investigator (Umezawa) and the co-workers have investigated the biosynthetic mechanisms of lignans and norlignans. Thus, they first established a system for comprehensive quantitative analysis of the cinnamate/monolignol pathway compounds which are precursors of lignans, norlignan, and lignins. Then, the molecular mechanisms of lignan biosynthesis and norlignan biosynthesis were studied. In addition, the genes encoding some enzymes of the cinnamate/monolignol pathway which is the upstream step of lignan, norlignan and lignin biosyntheses were also characterized. Less