Optimization of Indole Acetic Acid Production by Pseudomonas putida UB1 and its Effect as Plant Growth-Promoting Rhizobacteria on Mustard (Brassica nigra)

Abstract

Indole-3-acetic acid (IAA) production was monitored in nine plant growth-promoting rhizobacteria isolated from the rhizospheric soil of alfalfa (Medicago sativa). The isolate producing maximum amount of IAA was identified as Pseudomonas putida UB1 by 16S rRNA partial gene sequencing. Further investigations were carried out for optimal L-tryptophan concentration and other growth parameters for IAA production by P. putida. IAA production increased when the L-tryptophan medium for IAA production was supplemented with sucrose 0.5 %, (NH 4 ) 2 SO 4 10 mg/ml, and tryptophan 0.2 mg/ml at pH 7.5. Maximum IAA production was achieved at 96 h. Production of IAA was confirmed by extraction of crude IAA and subsequent thin-layer chromatography analysis. The specific spot from the extracted IAA was found to correspond with a spot of standard IAA with the same R f value (0.36). The crude IAA was further purified by passing it through a silica gel column. P. putida UB1 and its purified IAA were demonstrated to show stimulatory effect on mustard (Brassica nigra) plants in vitro with their incorporation in MS medium as a novel approach.

Plant growth‐promoting effects of native Pseudomonas strains on Mentha piperita (peppermint): an in vitro study

“…In the present study, each of the native strains was capable of producing IAA, and some of the observed effects were presumably due to the ability to utilise root exudates and synthesise plant growth regulators. Bharucha et al (2013) observed similar capacity in P. putida isolates from Medicago sativa.…”

Burkholderia sp. from rhizosphere of Rhododendron arboretum: Isolation, identification and plant growth promotory (PGP) activities

“…can improve the plant growth development and thus considered as an effective PGPR. Similar type of results was reported by Bharucha et al (2013), Sivakumar et al (2012) and Mia et al (2012).…”

Rizobactérias e desenvolvimento de mudas a partir de estacas semilenhosas de oliveira (Olea europeae L.)

“…Diversos fatores como tempo de incubação, aminoácidos, fontes de carbono e nitrogênio interferem diretamente na produção de hormônios pelos microrganismos, como demonstrado por Bharucha et al (2013) uma máxima produção de AIA na concentração de 0,20 mg/mL de triptofano, presença de sacarose como fonte de energia e (NH 4 ) 2 SO 4 como fonte de nitrogênio em um tempo de incubação de 96 h. Os isolados estudados apresentaram uma faixa de produção do AIA de 26,4 a 591,8 μg mL…”