Molecular and Pathological Factors involved in Sustainable Wood Quality

一般来说，树木在生理正常的情况下产生可持续的木材。当一棵树在生理上远离正常状态时，它可能会产生紊乱的木材。换句话说，生物和非生物的压力扰乱了“可持续”的木材质量。在正常的“可持续”木材形成过程中，涉及到各种遗传因素。在胁迫因子中，我们重点研究了抗真菌和耐寒基因。二苯乙烯合成酶通过cDNA克隆后的异源表达来抵御生物胁迫。针对非生物胁迫，对脱氢酶进行了克隆，并进行了生理、转基因和分子研究。我们提出了一个可靠的分子基础，“可持续”的木材质量或木材形成，与抗真菌和抗寒相关的因素。体外培养系统使复杂的非生物分析变得简单。在这里，研究了非生物胁迫，特别是温度和重金属的影响。培养系统响应产生次生代谢产物，特别是儿茶素，以尽可能保持生理正常状态。此外，次生代谢物在清除活性氧和解毒锰离子方面发挥了重要作用。在从亚北极到温带的广大地区对针叶林的健康状况进行了实地调查。除了对木材标本进行显微分析外，还对患病树木的生理方面进行了检查，例如使用声发射技术（AE）。结果表明，边材水分传导性对保持树木健康至关重要。总之，这些研究揭示了森林健康和木材质量健康或可持续木材质量的分子和病理基础。

Generally speaking, a tree produces sustainable wood under physiologically normal condition. When a tree is physiologically apart far from the normal condition, it may produce disordered wood. In other words, biotic and abiotic stresses disturb "sustainable" wood quality. Various genetic factors are involved in the process, or normal "sustainable" wood formation. Among the stress factors, we focused on anti-fungal and cold tolerant genes. Against the biotic stress, stilbene synthases have characterized by using heterologous expression after the cDNA cloning. Against the abiotic stress, dehydrin has cloned, being characterized by physiological, transgenic, and molecular studies. We have presented a reliable molecular basis on the "sustainable" wood quality or wood formation, in relation to anti-fungal and cold torelant factors.In vitro culture system makes complex abiotic analyses rather simple. Here, the effect of abiotic stress, especially temperature and a heavy metal, had examined. The culture system responded to produce secondary metabolites, especially catechins, in order to keep physiologically normal condition as far as possible. Furthermore, the secondary metabolites played an important role for scavenging active oxygen and detoxification of Mn ions.The field surveys on the health of conifer plantations were made covering wide area from the subarctic to temperate zones. In addition to microscopic analysis of wood specimens, physiological aspects were checked in diseased trees, for instance with acoustic emission technique (AE). The results indicated that the water conductivity of sapwood is most important to keep trees healthy.Altogether, the studies have revealed molecular and pathological bases in forest health and healthiness in the wood quality, or sustainable wood quality.