Isolation of plant-growth-promoting Bacillus strains from soybean root nodules.
Endophytic bacteria reside within plant tissues and have often been found to promote plant growth. Fourteen strains of putative endophytic bacteria, not including endosymbiotic Bradyrhizobium strains, were isolated from surface-sterilized soybean (Glycine max. (L.) Merr.) root nodules. These isolates were designated as non-Bradyrhizobium endophytic bacteria (NEB). Three isolates (NEB4, NEB5, and NEB17) were found to increase soybean weight when plants were co-inoculated with one of the isolates and Bradyrhizobium japonicum under nitrogen-free conditions, compared with plants inoculated with B. japonicum alone. In the absence of B. japonicum, these isolates neither nodulated soybean, nor did they affect soybean growth. All three isolates were Gram-positive spore-forming rods. While Biolog tests indicated that the three isolates belonged to the genus Bacillus, it was not possible to determine the species. Phylogenetic analysis of 16S rRNA gene hypervariant region sequences demonstrated that both NEB4 and NEB5 are Bacillus subtilis strains, and that NEB17 is a Bacillus thuringiensis strain.
Bai
Yuming
Y
Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, QC, Canada.
D'Aoust
Frederic
F
Smith
Donald L
DL
Driscoll
Brian T
BT
D001412:Bacillus subtilis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D001413:Bacillus thuringiensis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D004275:DNA, Ribosomal / Q000032:analysis; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013025:Glycine max / Q000254:growth & development* / Q000382:microbiology*
D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S