Tuesday, November 6, 2007
231-39

Characterization of Rhizosphere Bacteria of the Arsenic Hyperaccumulator Chinese Brake Fern (Pteris vittata L.).

Anhui Huang1, Max Teplitski1, Bala Rathinasabapathi2, and Lena Ma1. (1) University of Florida, Dep.-Soil & Water Sci.U.-FL, 2169 McCarty HallPOB 110290, Gainesville, FL 32611-0290, (2) University of Florida, Horticultural Sciences Department, Gainesville, FL 32611

Chinese Brake fern (Pteris vittata L.) is the first reported As hyperaccumulator, which can tolerate soil As concentration up to 1 500 mg/kg and can accumulate As up to 2.3% in its aboveground biomass. The model plant as well as its root exudates sustain unique rhizosphere microbial communities, which solubilize and provide bioavailable P and As to the plant through intensive root-microbe interactions. Research is underway to study the genetic and functional characters of the rhizosphere microbial communities of P. vittata. Three strains of arsenic resistant bacteria have been isolated with TYEG medium and genus Pseudomonas has been identified with the 16s rRNA method. A bacteria chromosome cDNA library will be constructed to screen arsenate resistant genes at chromosome loci from the bacteria grown in medium with inhibitory levels of arsenic and tested negatively with ars genes. Those As resistant bacteria which are able to solubilize P, especially phytic acid will be further studied by comparing their quality and quantity differences between rhizosphere soils in P. vittata and P. ensiformis, a non-arsenic-hyperaccumulator.