Flavonoids produced by roots are secondary metabolites involved in the induction of nod genes in rhizobial cells and nodule organogenesis. We describe the development and quality control of a new formulation for soybean (Glycine max (L.) Merr.) based on Bradyrhizobium elkanii cells grown in a culture medium containing isoflavones. As opposed to B. japonicum, the performance of B. elkanii pre-incubated with isoflavones is unknown. Its evaluation implied in vitro, greenhouse, and field research trials. Greenhouse and in vitro treatments comprised: seeds inoculated with a traditional inoculant based on B. elkanii; seeds inoculated with a new formulation based on isoflavones-cultivated B. elkanii cells, the exogenous application of isoflavones into the growth substrate, and the non-inoculated control. Field treatments included non-inoculated controls with and without N-fertilizer and seeds inoculation with the traditional or the new formulation. No changes in quality parameters (bacterial survival on both seeds and liquid formulation) were observed, as compared with the traditionally produced bradyrhizobial cells. Also, improved plant response (nodulation, plant growth, and seed yield) was observed when seeds were inoculated with the new formulation. The exogenous application of isoflavones directly into the substrate had deleterious effects on soybean growth and nodulation; however, the increased values of agronomical parameters in field conditions show that the addition of isoflavones during the industrial fermentation of B. elkanii is a better option over the common bradyrhizobial inoculant.

由根产生的类黄酮是次生代谢产物，参与了根瘤菌细胞中nod基因的诱导和根瘤的器官发生。我们描述了基于在含有异黄酮的培养基中生长的缓生根虫细胞的大豆（Glycine max（L.）Merr。）的新配方的开发和质量控制。与日本芽孢杆菌相反，与异黄酮预孵育的埃尔卡氏芽孢杆菌的性能未知。其评估暗示了体外，温室和野外研究试验。温室和体外处理包括：种子接种了传统的基于埃卡氏梭菌的接种剂; 基于异黄酮培养的B. elkanii的新配方接种的种子细胞，异黄酮在生长基质中的外源应用以及未接种的对照。田间处理包括使用和不使用氮肥的未接种对照，以及使用传统或新制剂接种的种子。与传统生产的缓生根瘤菌细胞相比，未观察到质量参数的变化（种子和液体制剂的细菌存活率）。同样，当用新制剂接种种子时，观察到改善的植物响应（结瘤，植物生长和种子产量）。将异黄酮直接外源施用到基质中会对大豆的生长和结瘤产生有害影响。然而，田间条件下农学参数值的增加表明，在工业发酵过程中添加了异黄酮。B. elkanii比普通的根瘤菌接种剂是更好的选择。