Division of Microbiology, Indian Agricultural Research Institute, New Delhi 110012, India.
Pol J Microbiol. 2010;59(2):99-105.
Cyanobacteria represent less a investigated group of prokaryote, in terms of their plant growth promoting potential, especially in relation to the production of phytohormones. The present investigation was aimed towards analyzing growth kinetics, indole acetic acid (IAA) production and acetylene reduction activity (ARA) as an index of nitrogen fixation in two selected cyanobacterial strains belonging to the genus Anabaena, as influenced by tryptophan supplementation and light:dark conditions. Interesting observations were recorded in terms of enhancement of IAA production accompanied by protein and chlorophyll accumulation in the two cyanobacterial strains grown in media without tryptophan and incubated under light:dark or continuous light conditions. Colorimetric and chromatographic analyses supported the observations that tryptophan is not essential as a precursor for IAA biosynthesis in these cyanobacteria. Further study is in progress to identify genes involved in the tryptophan independent pathway for IAA biosynthesis.
蓝细菌在促进植物生长方面的潜力，尤其是在植物激素的产生方面，是研究较少的原核生物类群。本研究旨在分析两种属于鱼腥藻属的蓝细菌菌株的生长动力学、吲哚乙酸（IAA）的产生和乙炔还原活性（ARA），作为氮固定的指标，这些指标受色氨酸补充和光照：黑暗条件的影响。有趣的观察结果记录在两个蓝细菌菌株的 IAA 产量增加方面，同时伴随着在没有色氨酸的培养基中生长并在光照：黑暗或连续光照条件下培养时的蛋白质和叶绿素的积累。比色和色谱分析支持了这样的观察结果，即色氨酸不是这些蓝细菌中 IAA 生物合成的必需前体。进一步的研究正在进行中，以确定参与色氨酸非依赖性途径的基因，用于 IAA 生物合成。
