Developing a genomic-based strategy to confirm microbial identity in bio-inputs containing multiple strains: an easy, fast, and low-cost multiplex PCR applied to inoculants carrying soybean Bradyrhizobium.

Brazil stands out in research, industrial development, and farmers' use of microbial inoculants, with an emphasis on getting benefits from the biological nitrogen fixation process with the soybean crop. Nowadays, about 140 million doses of inoculants are commercialized annually for the soybean in the country, and strain identification is achieved by rep-PCR, an effective but time-consuming method. Aiming to develop an easy, low-cost, and low-time-consuming method, we used a complete genome-based approach based on the unequivocal identification of unique genes present in the genomes of each of the four Bradyrhizobium strains used in commercial inoculants: Bradyrhizobium elkanii strains SEMIA 587 and SEMIA 5019, Bradyrhizobium japonicum SEMIA 5079, and Bradyrhizobium diazoefficiens SEMIA 5080.

Regulation of , and genes in CIAT 899 and their roles in the synthesis of Nod factors and in the symbiosis.

strain CIAT 899 possesses outstanding agronomic properties as it displays tolerance to environmental stresses, a broad host range and high effectiveness in fixing nitrogen with the common bean ( L.); in addition, it carries intriguing features such as five copies of the regulatory gene, and the capacity to synthesize a variety of nodulation factors (NFs), even in a flavonoid-independent manner, when submitted to abiotic stresses. However, the roles of several genes of the repertoire of CIAT 899 remain to be determined.

Opening the "black box" of nodD3, nodD4 and nodD5 genes of Rhizobium tropici strain CIAT 899.

Background: Transcription of nodulation genes in rhizobial species is orchestrated by the regulatory nodD gene. Rhizobium tropici strain CIAT 899 is an intriguing species in possessing features such as broad host range, high tolerance of abiotic stresses and, especially, by carrying the highest known number of nodD genes--five--and the greatest diversity of Nod factors (lipochitooligosaccharides, LCOs). Here we shed light on the roles of the multiple nodD genes of CIAT 899 by reporting, for the first time, results obtained with nodD3, nodD4 and nodD5 mutants.

Regulatory nodD1 and nodD2 genes of Rhizobium tropici strain CIAT 899 and their roles in the early stages of molecular signaling and host-legume nodulation.

Background: Nodulation and symbiotic nitrogen fixation are mediated by several genes, both of the host legume and of the bacterium. The rhizobial regulatory nodD gene plays a critical role, orchestrating the transcription of the other nodulation genes. Rhizobium tropici strain CIAT 899 is an effective symbiont of several legumes-with an emphasis on common bean (Phaseolus vulgaris)-and is unusual in carrying multiple copies of nodD, the roles of which remain to be elucidated.