Chemical Studies on the Infection Mechanism of Crown Gall Disease

1.农杆菌是一种土壤细菌，其中一种工业冠状球肿瘤在一个宽多样的植物。细菌和植物之间的肿瘤起源相互作用是一个自然的例子，是尤卡里奥特斯的遗传工程。事实上，肿瘤基因细菌受体是一个较大的Ti等离子体，其中的T-DNA区域在肿瘤转化过程中转移并整合到植物基因组中。然而，有相当多的信息可供参考，以引导早期过程进行肿瘤形成。如果要进一步研究肿瘤诱导的机制，那么就必须开发出一个化学探针，这将有助于探索肿瘤形成的早期步骤。我们已经找到了那些不会抑制A的增长的转变的人。肿瘤和对转化的植物细胞的非毒性物质。从链霉菌SP. KBFP-2025衍生出的几个氧唑霉素孤立的菌株，如双氮霉素型的两个活性化合物、julichrome Q_<1·3>和julimycin B-II，从链霉菌SP. TM-71分离，抑制冠球形成，但对该细菌和宿主植物是非毒性。这些化合物被管理到一个马铃薯盘12 - 24小时后，细菌难以抑制的冠状球形成，而且不再需要马铃薯盘。本建议是，这些化合物对转化过程的任何步骤都能产生影响，但没有毒性向转化的植物细胞的基因组整合了T-DNA。tumefaciens。这是有可能的，因为该系统的转变过程在12 - 24小时后完成。“因为这一假说的直接证明，因为一个定量的微观分析方法，一个转变的指标，是稳定的。”这一方法涉及以氟代化合物形式形成的苯并素与圭亚那地丁诺族的特征氨基酸组的反应的HPLC分析。改变的时间路线很有可能被这种方法所追踪。

1. Agrobacterium tumefaciens is a soil bacterium which induces crown gall tumors in a wide variety of dicotyledonous plants. This tumorigenic interaction between the bacterium and the plant is a natural example of the genetic engineering of eukaryotes. Indeed, the oncogenic bacterium harbors a large Ti plasmid, whose T-DNA region is transferred to and integrated into the plant genome during tumorous transformation. However, very little information is available concerning the early process leading to tumor formation. In order to study further the mechanism of tumor induction, it is necessary to develop a chemical probe that will help in exploring the early steps of tumor formation. We searched transformation inhibitors which do not inhibit the growth of A. tumefaciens and are nontoxic against the transformed plant cells.2. A few esters derived from oxazolomycin isolated from Streptomyces sp. KBFP-2025 as well as two active compounds of bisanthraquinone type, julichrome Q_<1・3> and julimycin B-II, isolated from Streptomyces sp. TM-71, inhibit crown gall formation, but are nontoxic against this bacterium and the host plant.3. These compounds administered to a potato disk 12 - 24 hours after the inoculation of the bacterium hardly inhibited crown gall formation, and no longer necrosed the potato disk. This suggests that these compounds act on any step of transformation process, but have no toxicity toward transformed plant cells whose genome has integrated the T-DNA of A. tumefaciens. It is probable that the transformation process of this system is completed within 12 - 24 hours after the inoculation. For a direct proof of this hypothesis, a quantitative microanalytical method of opines, indices of transformation, has to be established. This method involves HPLC analysis of fluorescent compound formed by reaction of benzoin with guanidino group of the characteristic amino acid. Time course of transformation will be possibly traced by this method.