Aims: To screen of the multiple plant growth promoting activities of some Bacillus thuringiensis strains isolated from Malian Agricultural soils and evaluate their ability to improve maize seed germination and seedling vigor in vitro. Study Design: Strains of Bacillus thuringiensis (Bt) used in this study belong to collection of the Laboratory of Research in Microbiology and Microbial Biotechnology (LaboREM-Biotech) isolated from different agricultural soils of Mali. Methodology: Different tests, namely: Phosphate solubilization, Siderophore production, Indol acetic acid cellulase and chitinase production tests were performed to confirm the PGP characteristic of the insecticidal B. thuringiensis strains screened. In vitro test was performed in the laboratory to confirm the capacity of these bacteria to enhance maize germination and seedling vigor. Results: All tested Bacillus strains solubilize efficiently insoluble phosphate, but BtI4″ showed the
Original Research Articlehighest clearance zone around its colony. In this study, except in BtI4', the siderophore production was significantly elevated in the other Bt strains tested. Only BtD5 was able to produce Indol acetic acid. Contrary, except BtD5, all the isolates produce chitinase and cellulase. Exept IAA, the isolate BtI4″ produce all the tested compounds and showed the highest % seed germination and seedling vigor.
Conclusion:In the current study, plant growth promotion analysis of three B. thuringiensis strains from Malian agricultural soils were assessed in relation with maize seed germination and seedling vigor. These tested Bt strains showed several plant growth-promoting characteristics. These activities may allow the use of these isolates for plant growth promotion. Future work will address the applications of the selected bacteria in biocontrol and plant growth promotion. Insect pest biocontrol, enhancement of plant nutrition and production of phytohormon are the mechanisms involved.
The objective of this work was to select the most active Bacillus thuringiensis (Bt) isolated from agricultural soils of Mali through the molecular characterization and the determination of insecticidal activities of the protein crystals, produced by these native isolates. Crystal proteins were extracted from B. thuringiensis culture, and characterized using the SDS-PAGE techniques. Their insecticidal activities were tested using third-instar larvae of Helicoverpa armigera in bioassay tests. The results showed that, of 62 B. thuringiensis treated, 52 isolates showed fragments varying between 10 and 140 kDa on 12% polyacrylamide gel. Cry1 and Cry2 protein crystals were recognized to be effective against Lepidoptera's larvae, which were found in 21% of the tested isolates. In addition to these two expected crystal protein weights, other molecular weights were observed at different proportions, suggesting the presence of other cry genes in the local B. thuringiensis isolates. Four native B. thuringiensis isolates were able to kill 95 to 100% of H. armigera 3rd-instar larvae. Only one native of B. thuringiensis isolate was able to kill 100% of the H. armigera larvae. This is the first study for molecular characterization of Malian native B. thuringiensis isolates, showing the efficacy of the native B. thuringiensis against an important agricultural insect pest.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.