Felestrino Érica B, Santiago Iara F, Freitas Luana da Silva, Rosa Luiz H, Ribeiro Sérvio P, Moreira Leandro M
Núcleo de Pesquisas em Ciências Biológicas, Universidade Federal de Ouro PretoOuro Preto, Brazil; Laboratório de Genômica e Interação Microrganismos-Ambiente, Departamento de Ciências Biológicas, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Campus Morro do CruzeiroOuro Preto, Brazil.
Laboratório de Ecologia e Biotecnologia de Leveduras, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais Belo Horizonte, Brazil.
Front Microbiol. 2017 Feb 10;8:172. doi: 10.3389/fmicb.2017.00172. eCollection 2017.
Soil is a habitat where plant roots and microorganisms interact. In the region of the Brazilian Iron Quadrangle (IQ), studies involving the interaction between microbiota and plants have been neglected. Even more neglected are the studies involving the holoparasite plant Mart. (Balanophoraceae). The geomorphological peculiarities of IQ soil, rich in iron ore, as well as the model of interaction between , its hosts and the soil provide a unique niche that acts as selective pressure to the evolution of plant growth-promoting bacteria (PGPB). The aim of this study was to prospect the bacterial microbiota of holoparasitic plant , its plant host and corresponding rhizosphere of IQ soil, and to analyze the potential of these isolates as PGPB. We obtained samples of 11 individuals of containing fragments of host and rhizosphere remnants, resulting in 81 isolates associated with Firmicutes and Proteobacteria phyla. The ability to produce siderophores, hydrocyanic acid (HCN), indole-3-acetic acid (IAA), nitrogen (N) fixation, hydrolytic enzymes secretion and inhibition of enteropathogens, and phytopathogens were evaluated. Of the total isolates, 62, 86, and 93% produced, respectively, siderophores, IAA, and were able to fix N. In addition, 27 and 20% of isolates inhibited the growth of enteropathogens and phytopathogens, respectively, and 58% were able to produce at least one hydrolytic activity investigated. The high number of isolates that produce siderophores and indole-3-acetic acid suggests that this microbiota may be important for adaptation of plants to IQ. The results demonstrate for the first time the biological importance of Brazilian IQ species as reservoirs of specific microbiotas that might be used as PGPB on agricultural land or antropized soils that needs to be reforested.
土壤是植物根系与微生物相互作用的栖息地。在巴西铁四角地区（IQ），涉及微生物群与植物相互作用的研究一直被忽视。更被忽视的是涉及全寄生植物Mart.（蛇菰科）的研究。IQ地区富含铁矿石的土壤的地貌特殊性，以及其宿主与土壤之间的相互作用模式，提供了一个独特的生态位，对促进植物生长的细菌（PGPB）的进化起到了选择性压力的作用。本研究的目的是探寻IQ土壤中全寄生植物、其植物宿主及相应根际的细菌微生物群，并分析这些分离物作为PGPB的潜力。我们采集了11株含有宿主片段和根际残余物的样本，共获得了81株与厚壁菌门和变形菌门相关的分离物。评估了这些分离物产生铁载体、氢氰酸（HCN）、吲哚-3-乙酸（IAA）、固氮、分泌水解酶以及抑制肠道病原体和植物病原体的能力。在所有分离物中，分别有62%、86%和93%能够产生铁载体、IAA并能够固氮。此外，分别有27%和20%的分离物抑制了肠道病原体和植物病原体的生长，58%的分离物能够产生至少一种所研究的水解活性。产生铁载体和吲哚-3-乙酸的分离物数量众多，表明这种微生物群可能对植物适应IQ地区很重要。结果首次证明了巴西IQ地区物种作为特定微生物群库的生物学重要性，这些微生物群可作为PGPB用于需要重新造林的农业土地或人为土壤。
