胶质类芽孢杆菌的表型及遗传多样性

Paenibacillus mucilaginosus is a widely used biofertilizer, providing P, K and N nutrients. In the present study, the diversity of 27 P. mucilaginosus strains in phenotype and genotype were investigated to find out the principal factor influencing the functions. The strains were characterized to show certain similar shared morphological and biochemical characteristics, yet they showed diversity in sizes of capsules and colonies, productions of polysaccharides and acid, P, and K-dissolution and N-fixation. The sizes of the colonies and capsules varied from 2.00-5.72 mm and 200.07-857.23 μm2, respectively. The polysaccharide production was 2.04-13.12 mgoml-1, which was positively correlated with capsule (r=0.714, P<0.05) and colony (r=0.824, P<0.05) sizes . The strains caused pH decrease from 1.21 to 2.62, which was positively correlated with the dissolution of P (r=0.777, P<0.05) and K (r=0.778, P<0.05). The concentration rangess of dissolved P and K were 0.05-102.72 mgol-1 and 0.02-27.92 mgol-1, respectively. The fixed total nitrogen was 0.47-18.28 mgol-1. The strains also showed genotypic diversity at gene, repetitive sequence and genome levels. Altogether 249 amplified bands were obtained using 18 primers in RAPD pattern, and the dendrogram showed that the strains were grouped into 2 clusters according to their origins. Each cluster was divided into two branches: one was clustered as the strains with higher polysaccharide and acid production, and the other was clustered as the strains with lower production. The gyrB gene and ERIC-PCR gave the similar results. In conclusion, as RAPD and gyrB gene showed good correspondence with polysaccharide and acid diversity, they can serve as biomarkers and thus be employed efficiently in species identi?cation and selection at a large scale.