Heavy Metals and Phytoremediation
Indriolo, Emily , Salt, David , Banks, Jo Ann .
Expression of putative arsenite effluxers in Pteris vittata.
Arsenic, a known toxin and carcinogen, is one of many elements that plants are exposed to in their environment. Pteris vittata (Pteridacae) is unique because it and its close relatives are the only known plant species that are able to tolerate and hyperaccumulate arsenic. P. vittata can hyperaccumulate up to 2% of its foliar dry weight as arsenic. The focus of our research is on the fundamental mechanisms that are necessary for P. vittata to tolerate and hyperaccumulate arsenic. We have identified from P. vittata two putatitve arsenite effluxers; PvACR3-1 was identified from a P. vittata EST database and the other, PvACR3-3 from complementation screen with a P. vittata cDNA library expressed in ZL13 yeast that are mutant for the arsenite transporter ACR3. PvACR3-1 does not complement the ZL13 yeast and is missing 12 amino acids of a putative transmembrane domain. By the use of quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR) we have studied the expression of the arsenite effluxers in response to the addition of 1mM potassium arsenate (KAs(V)) to the plantsí liquid culture media. 1mM KAs(V) is a concentration of arsenic that results in the hyperaccumlation of arsenic but does not affect the growth. We present the expression data for both P. vittata gametophytes and sporophytes that have been grown in liquid culture in response to arsenic. These data show that PvACR3-1 and PvACR3-3 have significantly different expression patterns in response to arsenic; while PvACR3-1 is constitutive in expression, PvACR3-3 is induced 4 fold 1 day after the addition of the KAs(V). Given that PvACR3-3 complements and shows induced expression as a result of the addition of arsenic, it suggests that PvACR3-3 may be involved in arsenic tolerance and hyperaccumulation in P. vittata. PvACR3-1 may not be involved in arsenic response as a result of the 12 amino acid deletion in the putative transmembrane domain as show by its inability to rescue the ZL13 yeast grown in the presence of arsenic.
Log in to add this item to your schedule
1 - Purdue University, Botany and Plant Pathology, 915 W. State Street, West Lafayette, IN, 47907, USA
2 - Purdue University, Horticulture and Landscape Architecture
3 - Purdue University, Botany and Plant Pathology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM