Quantification of indole-3-acetic acid from plant associated Bacillus spp. and their phytostimulatory effect on Vigna radiata (L.)

• Published in: World journal of microbiology & biotechnology Vol. 25; no. 3; pp. 519 - 526
• Main Authors: Ali, Basharat, Sabri, Anjum Nasim, Ljung, Karin, Hasnain, Shahida
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.03.2009; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Acetic acid; Applied Microbiology; Bacillus; Bacillus megaterium; Bacteria; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Environmental Engineering/Biotechnology; Flowers & plants; Forest Science; Fundamental and applied biological sciences. Psychology; Gas chromatography; Life Sciences; Metabolites; Microbiology; Original Paper; Physiology; Plant biology; Plant growth; Plant species; Pumilus; Rhizosphere; Skogsvetenskap; Studies; Vigna radiata; In vitro; Auxin; Gnotobiotic conditions; tryptophan; GC–MS analysis; Indole; Vigna radiata; Tryptophan; L-tryptophan; Bacillaceae; In vitro; Bacillales; Leguminosae; Dicotyledones; Angiospermae; Bacillus; Bacteria; Spermatophyta; GC-MS analysis; Acetic acid; Quantitative analysis
• DOI: 10.1007/s11274-008-9918-9
• ISSN: 0959-3993; 1573-0972

Sixteen Bacillus strains isolated from rhizosphere, histoplane and phyllosphere of different plant species were identified by 16S rDNA gene sequencing and evaluated for in vitro auxin production as well as growth stimulation of Vigna radiata (L.) Wilczek. Auxin production by Bacillus spp. in L-broth medium supplemented with 1,000 μg ml⁻¹ L-tryptophan ranges from 0.60 to 3.0 μg IAA ml⁻¹ as revealed by gas chromatography and mass spectrometric (GC-MS) analysis. Rhizospheric isolates exhibit relatively more IAA synthesis than histoplane and phyllosphere isolates. Plant microbe interaction experiments conducted under gnotobiotic conditions recorded 55.55, 46.46 and 46.20% increase in shoot length with Bacillus megaterium MiR-4, B. pumilus NpR-1 and B. subtilis TpP-1, respectively, over control. Bacillus inoculations also increased shoot fresh weight with B. megaterium MiR-4 (60.94%) and B. pumilus NpR-1 (37.76%). Highly significant positive correlation between auxin production analyzed by GC-MS and shoot length (r = 0.687**, P = 0.01) and shoot fresh weight (r = 0.703**, P = 0.01) was noted under gnotobiotic conditions. Similarly, significant correlation was also found between auxin production by Bacillus spp. (GC-MS analysis) and different growth parameters such as shoot length (r = 0.495*, P = 0.05), number of pods (r = 0.498*, P = 0.05) and grain weight (r = 0.537*, P = 0.05) at full maturity under natural wire house conditions. Results showed that auxin production potential of plant associated Bacillus spp. can be effectively exploited to enhance the growth and yield of V. radiata.