Ansari M M, Sridhar R
Laboratory of Molecular Plant Pathology, Central Rice Research Institute, Cuttack, Orissa, 753 006 India.
Folia Microbiol (Praha). 2000;45(6):531-7. doi: 10.1007/BF02818722.
Xanthomonas oryzae pv. oryzae, the causal organism of bacterial blight of rice which produces leaf blight as well as kresek (wilt) symptoms in plants were tested for indole, auxin production in culture supplemented with L-tryptophan. On the basis of indoleacetic acid (IAA) production the isolates were grouped into IAA-positive and IAA-negative. Out of 17 isolates, 11 were IAA-positive while 6 were IAA-negative. The isolates metabolized tryptophan through two different routes and the isolates vary in the pathway of tryptophan utilization. The IAA-positive isolates converted tryptophan to IAA as the end product, whereas the IAA-negative isolates formed anthranilate as an intermediate metabolite and finally produced pyrocatechol via the kynurenine pathway. Quantification of tryptophan metabolism revealed that the maximum production of IAA and pyrocatechol in culture occurred during 2-d incubation at 30 +/- 2 degrees C.
水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae）是导致水稻白叶枯病的病原菌，可使植物出现叶片枯萎以及急性凋萎（萎蔫）症状。对其在添加L-色氨酸的培养基中吲哚、生长素的产生情况进行了检测。根据吲哚乙酸（IAA）的产生情况，将分离菌株分为IAA阳性和IAA阴性。在17个分离菌株中，11个为IAA阳性，6个为IAA阴性。这些分离菌株通过两种不同途径代谢色氨酸，且在色氨酸利用途径上存在差异。IAA阳性分离菌株将色氨酸转化为最终产物IAA，而IAA阴性分离菌株则形成邻氨基苯甲酸作为中间代谢产物，最终通过犬尿氨酸途径产生儿茶酚。色氨酸代谢定量分析表明，在30±2℃培养2天时，培养基中IAA和儿茶酚的产量最高。
