Soil communities support great biodiversity, as well as their interaction with the plants, can be equally diverse. In this work, we focused our attention on investigating the effect of native rhizobia from Brazilian grassland as a plant growth-promoting rhizobacteria for grasses. We suggest that the positive effect of rhizobacteria on plants is context-dependent, and native species may present better adaptability under certain soil conditions (i.e. acidity, nutrient availability, interaction with other organisms in the rhizosphere). To explore this iteration among native rhizobia and grasses, we isolated rhizobia from Desmodium incanum, a native legume from Brazilian grassland, and inoculated on oats (Avena sativa) and maize (Zea mays). Firstly, we characterized the ability of those rhizobia in solubilizing phosphate and producing indole-acetic acid. Next, under greenhouse conditions, we inoculated grasses with the isolates that presented at least one mechanism of plant growth promotion. After 45 days, we measured the effect of those rhizobia on both morphological and nutritional attributes of grasses. Our finding showed that rhizobia isolated from Desmodium incanum improve the growth of grasses by increasing shoot and root biomass, plant height, and nutrient accumulation in leaves. The most efficient isolate was UFRGS-Dinc1, perhaps due to its ability in solubilize phosphate and produce indole-acetic acid. However, we also noted that UFRGS-Dinc3, that presented the highest phosphate solubilization index, and UFRGS-Dinc18, that produce only indole-acetic acid, could also promote plant growth of grasses. Our results provide pieces of evidence that native rhizobia from Desmodium incanum can promote the growth of grasses, indicating their potential in increasing the yield of crop cultures.

土壤群落支持丰富的生物多样性，并且它们与植物的相互作用也可以同样多样。在这项工作中，我们将注意力集中在研究巴西草原上的天然根瘤菌作为促进植物生长的草根瘤菌的作用。我们认为，根瘤菌对植物的积极影响取决于具体情况，在某些土壤条件下（例如酸度，养分利用率，与根际中其他生物的相互作用），本地物种可能表现出更好的适应性。为了探索这种在原生根瘤菌和草之间的迭代，我们从巴西草原的一种豆科植物Desmodium incanum中分离了根瘤菌，并接种在燕麦（Avena sativa）和玉米（Zea mays）上。）。首先，我们表征了那些根瘤菌溶解磷酸盐和生产吲哚乙酸的能力。接下来，在温室条件下，我们用表现出至少一种促进植物生长的机制的分离株接种草。45天后，我们测量了根瘤菌对草的形态和营养特性的影响。我们的发现表明从独角皮中分离出的根瘤菌通过增加茎和根的生物量，植物高度和叶片中的养分积累来改善草的生长。最有效的分离物是UFRGS-Dinc1，可能是由于它具有溶解磷酸盐并产生吲哚乙酸的能力。但是，我们还注意到呈现最高磷酸盐增溶指数的UFRGS-Dinc3和仅产生吲哚乙酸的UFRGS-Dinc18也可以促进草的植物生长。我们的研究结果提供了证据，表明来自印度十里香的天然根瘤菌能促进草的生长，表明它们具有增加作物栽培产量的潜力。