Products based on beneficial microorganisms, such as rhizobia, are used in agriculture to reduce or even completely replace the use of mineral fertilizers. In Brazil, rhizobia inoculants have been widely used in agriculture in the cultivation of legumes such as soybeans. Currently, the development of new formulations based on microorganisms has been made to improve the effectiveness of these products. Among these new technologies, the use of secondary bacterial metabolites has been studied to compose new formulations of inoculants. Inoculants enriched with metabolic extract from rhizobia have been showing promising results in plant growth promotion, but little is known about the isolated effects of the molecules contained in this extract, such as the lipochitoligosaccharides (LCOs), chitoligosaccharides (COs), and exopolysaccharides (EPS), when they are purified. In this study, one greenhouse and two field experiments were carried out to evaluate the effects of the addition of secondary metabolites from Rhizobium tropici CIAT 899 to the standard inoculation (SI) with Bradyrhizobium spp. on soybean nodulation, growth, and yield. Total metabolic extract containing LCOs (ME-LCO) and other secondary metabolism molecules, such as purified LCOs, COs, and EPS, were tested. In the greenhouse, it was observed that the addition of ME-LCO increased nodule number and shoot, root, and nodules dry weight in comparison to the SI. The SI + ME-LCO treatment significantly increased soybean grain yield by 7.6% compared to SI in the 2018/2019 cropping season. In 2019/2020, an increase of 3.1% was observed, but it was not statistically significant. The use of ME-LCO of R. tropici CIAT 899 in supplementation of Bradyrhizobium spp. soybean inoculants is very promising for the formulation of new generation inoculants.

基于有益微生物（如根瘤菌）的产品用于农业以减少甚至完全取代矿物肥料的使用。在巴西，根瘤菌接种剂已被广泛用于农业种植大豆等豆类。目前，已经开发出基于微生物的新配方以提高这些产品的有效性。在这些新技术中，已经研究了使用次级细菌代谢物来组成新的接种剂配方。富含根瘤菌代谢提取物的接种剂已在促进植物生长方面显示出可喜的结果，但对该提取物中所含分子的分离作用知之甚少，例如脂壳多糖 (LCO)、壳多糖 (CO) 和胞外多糖 (EPS) ), 当它们被净化时。在本研究中，进行了一次温室和两次田间试验，以评估添加来自Rhizobium tropici CIAT 899 到标准接种 (SI) 与Bradyrhizobium spp。对大豆结瘤、生长和产量的影响。测试了含有 LCOs (ME-LCO) 和其他次级代谢分子（例如纯化的 LCOs、COs 和 EPS）的总代谢提取物。在温室中，观察到与 SI 相比，添加 ME-LCO 增加了根瘤数量和芽、根和根瘤干重。与 SI 相比，SI + ME-LCO 处理在 2018/2019 种植季节显着提高了大豆籽粒产量 7.6%。在 2019/2020 年，观察到增长了 3.1%，但没有统计学意义。R. tropici CIAT 899的 ME-LCO在补充慢生根瘤菌中的应用属 大豆孕育剂在新一代孕育剂的配方中非常有前景。