Department of Soil Science, Laboratory of Soil Microbiology, São Paulo State University/College of Agriculture, Av. Pádua Dias, 11, CP 09, Piracicaba, SP 13418-900, Brazil.
World J Microbiol Biotechnol. 2013 Jan;29(1):163-71. doi: 10.1007/s11274-012-1169-0. Epub 2012 Sep 18.
Brachiaria brizantha is considered one of the preferred fodders among farmers for having high forage yield and large production of root mass. The association of beneficial bacteria with these grasses can be very valuable in the recovery of the pasture areas with nutritional deficiency. With the aim of studying this possibility, we carried out the sampling of soil and roots of B. brizantha in three areas (Nova Odessa-SP, São Carlos-SP and Campo Verde-MT, Brazil). Seventy-two bacterial strains were isolated and used in tests to evaluate their biotechnological potential. Almost all isolates presented at least one positive feature. Sixty-eight isolates produced analogues of indole-3-acetic acid, ten showed nitrogenase activity when subjected to the method of increasing the concentration of total nitrogen (total N) in the culture medium and sixty-five isolates showed nitrogenase activity when subjected to acetylene reduction technique. The partial sequencing of 16S rRNA of these isolates allowed the identification of seven main groups, with the prevalence of those affiliated to the genus Stenotrophomonas (69 %). At the end, this work elected the strains C4 (Pseudomonadaceae) and C7 (Rhodospirillaceae) as promising organisms for the development of inoculants due to their higher nitrogenase activity.
象草是农民首选的饲料之一，因为它具有高产草和大量根质量的特点。有益细菌与这些草的结合在恢复营养缺乏的牧场方面非常有价值。为了研究这种可能性，我们在三个地区（巴西的新奥达斯-SP、圣卡洛斯-SP 和坎波韦尔迪-MT）对象草的土壤和根系进行了采样。从土壤和根系中分离出 72 株细菌，并用于测试以评估其生物技术潜力。几乎所有的分离株都至少表现出一个积极的特征。68 株分离株产生吲哚-3-乙酸类似物，10 株在培养基中总氮（总氮）浓度增加的方法下显示出固氮酶活性，65 株在乙炔还原技术下显示出固氮酶活性。这些分离株的 16S rRNA 的部分测序允许鉴定出七个主要的群组，其中以 Stenotrophomonas 属为主（69%）。最后，这项工作选择了 C4（假单胞菌科）和 C7（红螺菌科）菌株作为有希望的接种剂开发的生物，因为它们具有更高的固氮酶活性。
