Transgenic expression of glucose dehydrogenase in Azotobacter vinelandii enhances mineral phosphate solubilization and growth of sorghum seedlings.
Bottom Line: Glucose dehydrogenase (gcd) gene from Escherichia coli, and Azotobacter-specific glutamine synthetase (glnA) and phosphate transport system (pts) promoters were isolated using sequence-specific primers in a PCR-based approach.Sorghum seeds were bacterized with the transgenic azotobacters and raised in earthen pots in green house.The transgenic azotobacters, expressing E. coli gcd, showed improved biofertilizer potential in terms of mineral phosphate solubilization and plant growth-promoting activity with a small reduction in nitrogen fixation ability.
Affiliation: Department of Plant Sciences, School of Life Sciences, University of Hyderabad, PO Central University, Hyderabad-500 046, Andhra Pradesh, India.Show MeSH
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Mentions: The transformants pMMB206, pMMBEPS1 and pMMBEGS1 of A. vinelandii AvOP had reduced growth in Burk's nitrogen‐free medium by about 26% compared with the wild type. Nitrogenase activity of these transformed strains was reduced by about 6% compared with wild type as assessed by acetylene reduction (Fig. 2). The transformants pMMB206, pMMBEPS1 and pMMBEGS1 reduced 4828, 4833 and 4812 µmol acetylene per OD of culture per 24 h, respectively, while the wild‐type strain reduced 5148 µmol during the same time. The phosphate solubilization by both these transformants in liquid NBRIP and Burk's media was more than the wild type (Fig. 3). A notable improvement in the release of inorganic phosphate from tricalcium phosphate was visible with transgenic strains early during the incubation and progressively increased at least up to 3 days in NBRIP liquid medium, with or without ammonium salts. The observed improvement sustained up to 6 days for both the transformants in the medium with ammonium salt. However, pMMBEGS1 was unable to sustain the improvement beyond 3 days. The absence of the ammonium salts did not affect the MPS ability of pMMBEPS1 at least up to 6 days.
Affiliation: Department of Plant Sciences, School of Life Sciences, University of Hyderabad, PO Central University, Hyderabad-500 046, Andhra Pradesh, India.