Ensifer meliloti overexpressing Escherichia coli phytase gene (appA) improves phosphorus (P) acquisition in maize plants.
The Escherichia coli phytase gene appA encoding enzyme AppA was cloned in a broad host range plasmid pBBR1MCS2 (lac promoter), termed pVA1, and transformed into the Ensifer meliloti 1020. Transformation of pVA1 in Ensifer meliloti {E. m (pVA1)} increased its phosphatase and phytase activity by ∼9- and ∼50-fold, respectively, compared to the transformants containing empty plasmid as control {E. m (pBBR1MCS2)}. The western blot experiments using rabbit anti-AppA antibody showed that AppA is translocated into the periplasm of the host after its expression. Ensifer meliloti harboring AppA protein {E. m (pVA1)} and {E. m (pBBR1MCS2)} could acidify the unbuffered phytate minimal media (pH 8.0) containing Ca-phytate or Na-phytate as sole organic P (Po) source to below pH 5.0 and released P. However, both {E. m (pVA1)} and {E. m (pBBR1MCS2)} neither dropped pH of the medium nor released P when the medium was buffered at pH 8.0 using Tris-Cl, indicating that acidification of medium was important for the enzymatic hydrolysis of phytate. Further experiments proved that maize plants inoculated with {E. m. (pVA1)} showed increase in growth under sterile semi solid agar (SSA) medium containing Na-phytate as sole P source. The present study could be helpful in generating better transgenic bioinoculants harboring phosphate mineralization properties that ultimately promote plant growth.
Department of Biochemistry, Faculty of Science, M. S. University of Baroda, Vadodara, Gujarat, 390 002, India. sindhurvikas@gmail.com.|Discipline of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban, 4000, Republic of South Africa. sindhurvikas@gmail.com.
Vikas
V
Sharma
Discipline of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Westville Campus), Private Bag X54001, Durban, 4000, Republic of South Africa.
Ajit
A
Kumar
Department of Microbiology, Faculty of Science, M. S. University of Baroda, Vadodara, Gujarat, 390 002, India.
G
G
Archana
Department of Biochemistry, Faculty of Science, M. S. University of Baroda, Vadodara, Gujarat, 390 002, India.
G Naresh
GN
Kumar
D010832:6-Phytase / Q000235:genetics / Q000378:metabolism*; D000135:Acid Phosphatase / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D016962:Sinorhizobium meliloti / Q000201:enzymology / Q000235:genetics; D003313:Zea mays / Q000378:metabolism* / Q000382:microbiology*
D029968:Escherichia coli Proteins; D010758:Phosphorus; D000135:Acid Phosphatase; D010744:Phosphoric Monoester Hydrolases; D010832:6-Phytase; C406788:appA protein, E coli
E. coli phytase; Ensifer meliloti; Maize; Phytate mineralization; appA overexpression