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Genetic Engineering of Cotton Rhizobacteria for Phosphate Solubilization

Principal Investigator: M. B. Khetmalas

Principal Co-investigators: J. C. Zak, Michael San Francisco, B. L. McMichael


Our goal in this project is to isolate and characterize a large number of the bacteria associated with cotton rhizosphere from the Lubbock soils focusing on their ability to colonize the rhizosphere and biological processes. We will introduce an efficient phosphate solubilizing gene (pyrroloquinoline quinone [PQQ] synthase) from a non-rhizosphere bacterium to Erwinia herbicola to one effective cotton-specific rhizobacterium (e.g. Pseudomonas fluorescence). We expect to increase phosphate content of the plant thereby increasing seedling disease resistance, root and seedling growth, improve cold hardiness and cotton yield.

Specific Objectives:

  • Isolate and characterize seasonal trends in bacterial species associated with cotton rhizospheres from the select soils in the Southern High Plains of Texas.
  • Evaluate the locally isolated bacteria for plant growth promotion and other biological activities (siderophore production, antifungal activity against cotton root rot fungal pathogens (Rhizoctonia solani, Thielaviopsis basicola, Phymatotrichum omnivorum), growth hormone secretion, plasmid presence, nitrogenase and pyrroloquinoline quinone (PQQ) synthase activity.
  • Construct a plasmid vector either from the resident rhizosphere colonizer(s) or a foreign vector with pyrroloquinoline quinone (PQQ) synthase gene and a reporter gene and to transform in an effective identified strain(s) of rhizosphere colonizer(s) with the vector having PQQ synthase and reporter gene.
  • Evaluate a genetically modified organism (GMO) for root colonization (endorhiza and rhizoplane), in vitro activity / expression of pyrroloquinoline quinone (PQQ) synthase gene and in vivo expression.

Impact of Biodegradation of Aldicarb on Nematode and Thrips Control on Cotton

Principal Investigator: T. Wheeler

Co-Principal Investigators: J. Leser, W. Keeling


  • Determine if biodegradation of aldicarb occurs in this region.
  • Develop strategies, which reduce or eliminate biodegradation of aldicarb.
  • If there are no strategies evaluated that are successful in eliminating or reducing biodegradation, then alternatives using other separate control strategies for insects and nematodes would be evaluated.