PYI: Molecular Genetics of Forest Trees

在这个为期五年的总统青年研究者奖的初始阶段，Steven H. Strauss博士（俄勒冈州立大学）的研究活动将集中在森林树木的分子系统发育上，而在资助期的后期，工作将集中在基因工程方面(基因转移系统，树-病原体相互作用，以及基因表达的控制)。在分子系统发育方面，Strauss的实验室研究了针叶树的叶绿体基因组定位和限制性位点分析。PCR（聚合酶链反应）方法，加上扩增DNA的自动基因测序，有望为植物系统发育和控制分子进化速度和模式的因素提供重要的新见解。基因工程的进展取决于基因转移系统的发展，这将使“外来”基因融入植物。目前的工作旨在将昆虫病原体苏云金杆菌的毒素基因插入针叶树的基因组中。发展这样一种防止森林害虫破坏的手段，其潜在的经济优势是巨大的。将尝试表征花旗松主要根病原体的分子生理学。人们的期望是，这样就有可能分离和修饰致病基因，从而深入了解宿主-病原体的相互作用，并建立可行的树木抗病遗传系。最后，本研究最具科学野心的目标是操纵控制基因表达的系统。这将首先涉及在针叶树中控制组织特异性和环境反应性基因表达的主要控制序列的特征。因此，应该有可能将所需的序列拼接到各种目标针叶树基因上。

During the initial phase of this five-year Presidential Young Investigator Award's duration, research activities of Dr. Steven H. Strauss (Oregon State University) will focus on the molecular phylogeny of forest trees, whereas efforts during the latter part of the funding period will concentrate on genetic engineering aspects (gene transfer systems, tree-pathogen interactions, and control of gene expression). With regard to molecular phylogeny, studies in Strauss' laboratory have dealt with chloroplast genome mapping and restriction site analysis of conifers. The PCR (polymerase chain reaction) method, coupled with automated gene sequencing of amplified DNA, is expected to provide major new insights into the phylogeny of plants and factors controlling molecular evolution's tempo and mode. The progression to a genetic engineering focus is dependent upon development of gene transfer systems that will enable incorporation of "foreign" genes into plants. Current work is aimed at insertion of toxin genes from the insect pathogen, Bacillus thuringensis, into the genomes of coniferous trees. The potential economic advantages of developing such a deterrent to damage from forest insect pests are enormous. Attempts will be made to characterize the molecular physiology of a major root pathogen of Douglas fir trees. The expectation is that it will then be possible to isolate and modify the genes responsible for pathogenicity, thereby gaining insights into host-pathogen interactions and making feasible disease-resistant genetic lines of trees. Finally, the most scientifically ambitious goals of this research are directed toward manipulation of the systems controlling gene expression. This will first involve characterization of the major control sequences governing tissue-specific and environmental-responsive gene expression in conifers. Thereafter, it ought to be possible to splice desired sequences onto various target conifer genes.