title: Genetic diversity of cultivable plant growth-promoting rhizobacteria in Korea.
abstract: To elucidate the biodiversity of plant growth-promoting rhizobacteria (PGPR) in Korea, 7,638 bacteria isolated from the rhizosphere of plant species growing in many different regions were screened. A large number of PGPR were identified by testing the ability of each isolate to promote the growth of cucumber seedlings. After redundant rhizobacteria were removed via amplified rDNA restriction analysis, 90 strains were finally selected as PGPR. On the basis of 16S ribosomal RNA sequences, 68 Gram-positive (76%) and 22 Gram-negative (24%) isolates were assigned to 21 genera and 47 species. Of these genera, Bacillus (32 species) made up the largest complement, followed by Paenibacillus (19) and Pseudomonas (11). Phylogenetic analysis showed that most of the Grampositive PGPR fell into two categories: low- and high- G+C (Actinobacteria) strains. The Gram-negative PGPR were distributed in three categories: alpha-proteobacteria, beta- proteobacteria, and gamma-proteobacteria. To our knowledge, this is the largest screening study designed to isolate diverse PGPR. The enlarged understanding of PGPR genetic diversity provided herein will expand the knowledge base regarding beneficial plant-microbe interactions. The outcome of this research may have a practical effect on crop production methodologies.
authors.affiliation: Microbial Safety Division, National Academy of Agricultural Science, Rural Development Administration (RDA), Suwon 441-707, Republic of Korea. kimwi@korea.kr
authors.forename: Won-Il
authors.initials: WI
authors.lastname: Kim
authors.forename: Won Kyong
authors.initials: WK
authors.lastname: Cho
authors.forename: Su-Nam
authors.initials: SN
authors.lastname: Kim
authors.forename: Hyosub
authors.initials: H
authors.lastname: Chu
authors.forename: Kyoung-Yul
authors.initials: KY
authors.lastname: Ryu
authors.forename: Jong-Chul
authors.initials: JC
authors.lastname: Yun
authors.forename: Chang-Seuk
authors.initials: CS
authors.lastname: Park
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D018553:Cucumis sativus / Q000254:growth & development / Q000382:microbiology; D014644:Genetic Variation; D007723:Korea; D008969:Molecular Sequence Data; D010802:Phylogeny; D063245:Plant Development; D010944:Plants / Q000382:microbiology*; D058441:Rhizosphere; D012988:Soil Microbiology