Identification of an indole-3-acetic acid-producing plant growth-promoting bacterium (PGPB) isolated from the roots of Centrosema pubescens Benth.

Issue Date

6-2006

Abstract

Isolate TCeRe 37w obtained from the root extract of butterfly-pea (Cenfrosema pubescens Benth.) was found previously to produce indole-3-acetic acid (IAA) and promote the growth of plants. Colorimetric (Salkowski) assay exhibited a production of 291 and 736 μg IAA equivalent mL-1 of minimal salts medium supplemented with 1000 ppm tryptophan after 24 and 48 h of incubation, respectively. HPLC analysis confirmed the production of 116 μg IAA mL-1 of culture after 48 h. Biochemical characterization using API 20E indicated that TCeRe 37w belongs to the genus Klebsiella. The major fatty acids of TCeRe 37w include C16:0, C18:1 w7c and C17:0 CYCLO. In addition, straight chain, unsaturated, cyclo-propane and hydroxy fatty acids make up 39.75%, 24.57%, 14.48% and 0.65%, respectively, of its total cellular fatty acid. This fatty acid profile is most similar to that of Klebsiella pneumoniae-pneumoniae-GC subgroup B with a similarity index of 0.848. Alignment of the partial 168 rDNA sequence of TCeRe 37w showed closest relation with the 168 rDNA of Klebsiella pneumoniae. BLAST analysis further supports that the isolate is K. pneumoniae exhibiting 521 similar nucleotides out of 526 total nucleotides aligned (99% identity).

Source or Periodical Title

Philippine Agricultural Scientist

ISSN

317454

Volume

89

Issue

2

Page

149-156

Document Type

Article

Language

English

Subject

16S rDNA, BLASTn, Butterfly-pea, Centrosema pubescens Benth, Fatty acid profile, HPLC, IAA, Identification, Klebsiella pneumoniae TCeRe 37w

Digital Copy

none

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