Khan Abdul Latif, Waqas Muhammad, Kang Sang-Mo, Al-Harrasi Ahmed, Hussain Javid, Al-Rawahi Ahmed, Al-Khiziri Salima, Ullah Ihsan, Ali Liaqat, Jung Hee-Young, Lee In-Jung
Department of Biological Sciences and Chemistry, University of Nizwa, Nizwa, Oman.
J Microbiol. 2014 Aug;52(8):689-95. doi: 10.1007/s12275-014-4002-7. Epub 2014 Jul 4.
Plant growth promoting endophytic bacteria have been identified as potential growth regulators of crops. Endophytic bacterium, Sphingomonas sp. LK11, was isolated from the leaves of Tephrosia apollinea. The pure culture of Sphingomonas sp. LK11 was subjected to advance chromatographic and spectroscopic techniques to extract and isolate gibberellins (GAs). Deuterated standards of [17, 17-(2)H2]-GA4, [17, 17-(2)H2]-GA9 and [17, 17-(2)H2]-GA20 were used to quantify the bacterial GAs. The analysis of the culture broth of Sphingomonas sp. LK11 revealed the existence of physiologically active gibberellins (GA4: 2.97 ± 0.11 ng/ml) and inactive GA9 (0.98 ± 0.15 ng/ml) and GA20 (2.41 ± 0.23). The endophyte also produced indole acetic acid (11.23 ± 0.93 μM/ml). Tomato plants inoculated with endophytic Sphingomonas sp. LK11 showed significantly increased growth attributes (shoot length, chlorophyll contents, shoot, and root dry weights) compared to the control. This indicated that such phyto-hormones-producing strains could help in increasing crop growth.
促进植物生长的内生细菌已被确认为作物潜在的生长调节剂。内生细菌鞘氨醇单胞菌属（Sphingomonas sp.）LK11，是从紫穗槐（Tephrosia apollinea）叶片中分离得到的。鞘氨醇单胞菌属LK11的纯培养物采用先进的色谱和光谱技术来提取和分离赤霉素（GAs）。使用[17, 17-(2)H2]-GA4、[17, 17-(2)H2]-GA9和[17, 17-(2)H2]-GA20的氘代标准品来定量细菌产生的赤霉素。对鞘氨醇单胞菌属LK11的培养液分析表明，存在生理活性赤霉素（GA4：2.97±0.11 ng/ml）以及无活性的GA9（0.98±0.15 ng/ml）和GA20（2.41±0.23）。该内生菌还产生吲哚乙酸（11.23±0.93 μM/ml）。与对照相比，接种内生鞘氨醇单胞菌属LK11的番茄植株生长特性（茎长、叶绿素含量、茎和根干重）显著增加。这表明这类产生植物激素的菌株有助于促进作物生长。
