Castro Renata Assis, Dourado Manuella Nóbrega, Almeida Jaqueline Raquel de, Lacava Paulo Teixeira, Nave André, Melo Itamar Soares de, Azevedo João Lucio de, Quecine Maria Carolina
University of São Paulo, Escola Superior de Agricultura "Luiz de Queiroz", Department of Genetics, Piracicaba, SP, Brazil; University of São Paulo, Center for Nuclear Energy in Agriculture (CENA), Piracicaba, SP, Brazil.
University of São Paulo, Biomedical Science Institute, Department of Microbiology, São Paulo, SP, Brazil.
Braz J Microbiol. 2018 Jan-Mar;49(1):59-66. doi: 10.1016/j.bjm.2017.04.002. Epub 2017 Jul 19.
Mangroves are ecosystems located in the transition zone between land and sea that serve as a potential source of biotechnological resources. Brazil's extensive coast contains one of the largest mangrove forests in the world (encompassing an area of 25,000km along all the coast). Endophytic bacteria were isolated from the following three plant species: Rhizophora mangle, Laguncularia racemosa and Avicennia nitida. A large number of these isolates, 115 in total, were evaluated for their ability to fix nitrogen and solubilize phosphorous. Bacteria that tested positive for both of these tests were examined further to determine their level of indole acetic acid production. Two strains with high indole acetic acid production were selected for use as inoculants for reforestation trees, and then the growth of the plants was evaluated under field conditions. The bacterium Pseudomonas fluorescens (strain MCR1.10) had a low phosphorus solubilization index, while this index was higher in the other strain used, Enterobacter sp. (strain MCR1.48). We used the reforestation tree Acacia polyphylla. The results indicate that inoculation with the MCR1.48 endophyte increases Acacia polyphylla shoot dry mass, demonstrating that this strain effectively promotes the plant's growth and fitness, which can be used in the seedling production of this tree. Therefore, we successfully screened the biotechnological potential of endophyte isolates from mangrove, with a focus on plant growth promotion, and selected a strain able to provide limited nutrients and hormones for in plant growth.
红树林是位于陆地与海洋过渡地带的生态系统，是生物技术资源的潜在来源。巴西广阔的海岸拥有世界上最大的红树林之一（沿海岸线总面积达25000平方公里）。从以下三种植物物种中分离出内生细菌：红树、拉贡木和亮叶白骨壤。对总共115株分离菌株进行了固氮和磷溶解能力评估。对这两项测试均呈阳性的细菌进一步检测其吲哚乙酸的产生水平。选择两株吲哚乙酸产量高的菌株作为造林树木的接种剂，然后在田间条件下评估植物的生长情况。荧光假单胞菌（菌株MCR1.10）的磷溶解指数较低，而所用的另一菌株肠杆菌（菌株MCR1.48）的该指数较高。我们使用的造林树种是多叶相思。结果表明，接种MCR1.48内生菌可增加多叶相思的地上部干质量，表明该菌株能有效促进植物生长和健康，可用于该树种的苗木生产。因此，我们成功筛选了红树林内生菌分离株的生物技术潜力，重点是促进植物生长，并选择了一株能够为植物生长提供有限养分和激素的菌株。
