U.S.-Japan Cooperative Research: Comparative Biochemistry of1-Aminocyclopropane-1-carboxylate Synthase Isolated from Plant Tissues

该奖项将促进美日合作科学计划下的一个项目的合作，该项目涉及乙烯作为一种植物激素的作用，该激素调节植物生长和发育的许多方面，包括果实成熟、叶片衰老和花朵枯萎。植物中乙烯的化学前体是化合物1-氨基环丙烷-1-羧酸(ACC)。这种化合物是由S-腺苷甲硫氨酸(SAM)产生的。植物中乙烯生物合成的限速步骤已被证明是由被称为ACC合成酶的酶催化的SAM到ACC的转化。正是对这种从植物组织中分离出来的酶的研究，形成了这个合作项目的主题。众所周知，各种发育、激素和环境因素，如生长素处理或植物伤害，都会导致ACC合成酶的诱导，导致乙烯产量的显著增加。然而，以这些不同的方式诱导的ACC合成酶似乎在免疫学和物理化学性质上表现出不同。本研究的目的是在蛋白质和基因水平上阐明不同因素在不同组织中诱导的ACC合成酶的比较生物化学。该项目的美国主要研究人员是加州大学戴维斯分校蔬菜作物系的尚发·杨博士和艾伦·B·班尼特博士。他们的日本同事是名古屋大学的Hidemasa Imaseki博士和东北大学的Shigeru Satoh博士。这家美国集团正在研究西红柿和苹果，这家日本集团正在研究南瓜和其他植物的同样过程。两个小组分离的纯化材料将进行交流和测试，并将分享信息和专业知识。在这些研究中获得的结果应该有助于进一步了解受乙烯调控的那些基本植物过程。这一知识有可能被用于通过生物技术控制这些过程，从而对农业产生重大意义。

This award will facilitate collaboration under the U.S.-Japan Cooperative Science Program on a project concerned with the role of ethylene as a plant hormone which regulates many aspects of plant growth and development, including fruit ripening, leaf senescence, and flower fading. The chemical precursor of ethylene in plants is the compound 1- aminocyclopropane-1-carboxylic acid (ACC). This compound in turn is produced from S-adenosylmethionine (SAM). The rate- limiting step in ethylene biosynthesis in plants has been shown to be the conversion of SAM to ACC, catalyzed by the enzyme known as ACC synthase. It is the study of this enzyme, isolated from plant tissues, that forms the subject of this cooperative project. It is known that various developmental, hormonal, and environmental factors, such as auxin treatment or plant wounding, cause the induction of ACC synthase, resulting in marked increase in ethylene production. However, the ACC synthase induced in these different ways appears to show differences in its immunological and physicochemical properties. The goal of this research is to elucidate, at both the protein and gene levels, the comparative biochemistry of ACC synthase induced in different tissues by different factors. The U.S. principal investigators in this project are Dr. Shang Fa Yang and Dr. Alan B. Bennett, Department of Vegetable Crops, University of California, Davis. Their Japanese colleagues are Dr. Hidemasa Imaseki, Nagoya University, and Dr. Shigeru Satoh, Tohoku University. The U.S. group is working with tomato and apple, and the Japanese group is studying the same process in squash and other plants. Purified materials isolated by the two groups will be exchanged and tested, and information and expertise will be shared. Results obtained during these studies should lead to further understanding of those basic plant processes regulated by ethylene. This knowledge can potentially be exploited in the control of these processes via biotechnology, with resulting significance in agriculture.