title: Solubilization of insoluble zinc compounds by Gluconacetobacter diazotrophicus and the detrimental action of zinc ion (Zn2+) and zinc chelates on root knot nematode Meloidogyne incognita.
abstract: OBJECTIVE
  To examine the zinc (Zn) solubilization potential and nematicidal properties of Gluconacetobacter diazotrophicus.
  
  
  RESULTS
  Atomic Absorption Spectrophotometer, Differential Pulse Polarography and Gas Chromatography Coupled Mass Spectrometry were used to estimate the total Zn and Zn(2+) ions and identify the organic acids present in the culture supernatants. The effect of culture filtrate of Zn-amended G. diazotrophicus PAl5 on Meloidogyne incognita in tomato was examined under gnotobiotic conditions. Gluconacetobacter diazotrophicus PAl5 effectively solubilized the Zn compounds tested and 5-ketogluconic acid was identified as the major organic acid aiding the solubilization of zinc oxide. The presence of Zn compounds in the culture filtrates of G. diazotrophicus enhanced the mortality and reduced the root penetration of M. incognita under in vitro conditions.
  
  
  CONCLUSIONS
  5-ketogluconic acid produced by G. diazotrophicus mediated the solubilization process and the available Zn(2+) ions enhanced the nematicidal activity of G. diazotrophicus against M. incognita.
  
  
  CONCLUSIONS
  Zn solubilization and enhanced nematicidal activity of Zn-amended G. diazotrophicus provides the possibility of exploiting it as a plant growth promoting bacteria.
authors.affiliation: School of Bio-Engineering and Bio-Sciences, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India. saraphd2003@yahoo.com
authors.forename: V S
authors.initials: VS
authors.lastname: Saravanan
authors.forename: P
authors.initials: P
authors.lastname: Kalaiarasan
authors.forename: M
authors.initials: M
authors.lastname: Madhaiyan
authors.forename: M
authors.initials: M
authors.lastname: Thangaraju
mesh_terms: D000818:Animals; D000969:Antinematodal Agents / Q000494:pharmacology*; D008401:Gas Chromatography-Mass Spectrometry; D041821:Gluconacetobacter / Q000378:metabolism*; D005942:Gluconates / Q000378:metabolism; D018551:Solanum lycopersicum / Q000469:parasitology; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000469:parasitology*; D018517:Plant Roots / Q000469:parasitology; D012995:Solubility; D014431:Tylenchoidea / Q000187:drug effects*; D015032:Zinc / Q000494:pharmacology*; D017967:Zinc Compounds / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D000969:Antinematodal Agents; D005942:Gluconates; D017967:Zinc Compounds; C093583:5-ketogluconic acid; D015032:Zinc