Screening of plant growth promoting traits ofBacillus thuringiensis

Abstract

-This study aimed to evaluate the plant growth promoting (PGP) potential of Bacillus thuringiensis. In this context, several genetic determinants of factors implicated in PGP potential were investigated by polymerase chain reaction (PCR) in 16 B. thuringiensis strains of different origin and belonging to different subspecies. PCR screening was performed on acid phosphatase, phytase, siderophore biosynthesis protein, 1-aminocyclopropane-1-carboxylate (ACC) deaminase and indolpyruvate decarboxylase (ipdC). Production of indol acetic acid (IAA)-like compounds and of ACC deaminase, and capability of solubilising mineral phosphate were investigated by phenotypic tests. All the strains were PCR positive for the presence of the siderophore biosynthesis protein, ACC deaminase and acid phosphatase genes. Five and seven strains gave an amplicon with the expected length for the phytase and ipdC genes respectively. All the strains produced IAA compounds and seven had a high capacity to solubilise inorganic phosphorous. Qualitative phenotypic test for ACC deaminase activity showed that seven strains are able to grow on salt minimal medium containing ACC as sole nitrogen source, indicating the expression of the accd genes. Our screening results in thirteen strains having more than one PGP trait and showed that B. thuringiensis harbours and expresses several PGP determinants that could be very interesting in field application to enhance the plant growth. To our knowledge, this is the first report on the multiple plant growth promoting potential of B. thuringiensis.

Gibberellins synthesized by the entomopathogenic bacterium, Photorhabdus temperata M1021 as one of the factors of rice plant growth promotion

“…In the present study, we detected different bioactive and inactive GAs in the CF of M1021, and these results are strongly supported by earlier reports suggesting that entomopathogenic bacteria produce plant hormones. Raddadi et al (2008) have reported that several strains of Bacillus thuringiensis produce various growth-promoting metabolites including phytohormones. Similarly, Ullah et al (2013) have reported that P. temperata produces plant growth hormones.…”

“…(Goswami et al 2013) have been successfully analyzed for the GAs production. Entomopathogenic bacteria have been recently reported to produce plant growth regulators (Raddadi et al 2008), that not only improve plant growth and development but also enhance the fitness of the host against a diverse array of environmental stresses Kang et al 2012). Bacteria produce GAs in culture extract that can be detected using gas chromatography coupled with mass spectrometry (GC/ MS) with selected ion monitoring mode (SIM), which has been used extensively for the analysis of metabolites because of its greater separation efficiency that resolves very complex biological mixtures (Schneider et al 1985).…”

Epiphytic and endophytic bacteria that promote growth of ethnomedicinal plants in the subtropical forests of Meghalaya, India

“…The gene encoding for 1-aminocyclopropane-1-carboxylic acid deaminase is ~800bp (Raddadi, Cherif, Boudabous & Daffonchio, 2008). The primers used were forward 5'-GTGAAC-CACCTGAATGTA-3' and reverse 5'-AAAC-GAGATGATTTACTTGG-3'.…”

Plant growth promoting and antagonistic properties of endophytic bacteria isolated from domestic apple

“…Pseudomonas fluorescens group (Ga_1, Oa_2, D_6), P. vagans (D_10) and P. stutzeri (O_16) produced moderate to low quantities of IAA. Other authors reported varying levels of IAA production for different endophytic strains: 18.8 μg ml -1 for P. stutzeri, isolated from Echinacea (Lata et al, 2006), 6-13.3 μg ml -1 for Methylobacterium, isolated from clover, 0.6-45.5 μg ml -1 for endophytes from Sedum alfredii and 1.1-154 μg ml -1 for endophytes from Solanum nigrum (Raddadi et al, 2008).…”