Poster: Membrane transport

Abs # 174: Role of ABC transporter AtWBC19 in response to xenobiotics

Presenter:	Ayalew, Mentewab B, mayalew@utk.edu
Authors	Ayalew, Mentewab B (A)   Stewart, C. Neal  (A)
Affiliations:	(A): University of Tennessee-Knoxville

AtWBC19 encodes for a half molecule transporter of 725 amino acids. It belongs to the subfamily of WBC (White-Brown Complex) homologs, the largest subfamily in Arabidopsis with 29 members. It is a homologue of human ABCG2 and mouse BCRP1 that contribute to multidrug resistance of cancer cells. Microarray experiments and real-time PCR assays have shown that AtWBC19 is upregulated during plant exposure to 10 μ TNT (2,4,6 trinitrotoluene), 20 μ RDX (hexahydro-1,3,5-trinitro,-1,3,5-triazine) and 20 mM TDG (thiodiglycol or 1,2-ethanedithiol). An Arabidopsis knockout mutant (SALK_107731) was obtained from TAIR and assessed for TNT sensitivity. Growth was significantly slower in SALK_107731 plants compared to wild-type Col1 at 1μ TNT (T-Test, P=0.0021). Growth was also significantly reduced by 20 ìM RDX (T-Test, P<0.0013), despite the fact that RDX is not considered toxic and in our experiments a concentration of 20 μ did not show any signs of toxicity towards wild-type plants. Transgenic plants over-expressing AtWBC19 were produced and screened against TNT and RDX as well as additional xenobiotics. Results indicate that AtWBC19 has a wide range of substrate specificity, a common feature of ABC transporters.