Poster: Late and Moved Abstracts

Abs # 1437: ANALYSIS OF SAFENER-INDUCIBLE EXPRESSED SEQUENCE TAGS (ESTs) FROM POPULUS

Presenter:	Goyal, Arun , agoyal@d.umn.edu
Authors	Goyal, Arun  (A)   Rishi, A.S.  (A)   Kapur, Vivek  (B)   Nelson, Neil D. (A)
Affiliations:	(A): NRRI, University Of Minnesota Duluth (B): Microbiology, University Of Minnesota, Minneapolis

Safeners are compounds that selectively protect crops against herbicide damage. Safeners act by enhancing the metabolism of herbicides in three phases; viz., oxidation, conjugation, and sequestering. The mechanism of safener action has been studied mainly in monocots and in a few dicot plants. In an effort to identify homologous genes that are involved in safener/herbicide metabolism in hybrid poplar, safener-inducible Expressed Sequence Tags (ESTs) were generated using the Suppressive Subtractive Hybridization (SSH) technique. A set of 1,344 EST clones were analyzed using contig and BlastX analysis, resulting in 745 to 804 hits, respectively, with a redundancy of 69%. Putative functions of over half of the clones have not been identified (32% no match in GeneBank database and 22% of unknown function). Only 30% of the clones showed matches with the Populus EST database, providing insight that a majority of the ESTs are unique (have not been previously identified in poplar). Genes that are involved in all three phases of herbicide detoxification, which were earlier identified to be induced by safener in other crop species, were found in the library, indicating that the SSH strategy was effective in identifying safener-inducible ESTs. The EST clones were used to construct a cDNA microarray, and experiments were conducted to identify highly expressed safener-inducible genes in hybrid poplar. Many of the genes that were highly expressed after safener treatment were not found in the Populus database. Results will be presented on using safener-induced ESTs and cDNA microarrays to identify homologous genes that are induced by safener treatment in hybrid poplar