Poster: Mineral nutrition

Abs # 195: Elucidation of cis-elements in White Lupin Phosphorus Deficiency Signaling

Presenter:	Zinn, Kelly E, zinn0009@umn.edu
Authors	Zinn, Kelly E (A) (B)  Liu, Junqi  (B)   Uhde - Stone, Claudia  (A) (B)  Allan, Deborah L (A)   Vance, Carroll P (B) (C)
Affiliations:	(A): Department of Soil, Water, and Climate, University of Minnesota (B): Department of Agronomy and Plant Genetics, University of Minnesota (C): USDA-ARS, Plant Science Research Unit

Phosphorus (P) deficiency stress in white lupin results in tightly coordinated physiological and morphological responses that give rise to cluster roots. One approach to elucidating the signaling pathway for P-deficiency is to determine whether specific nucleotide motifs in the promoter region of P-responsive genes confer P-deficiency specific expression. We have isolated and sequenced the 5’- upstream putative promoters for four white lupin proteoid root P-deficiency induced genes including an acid phosphatase (LaAPase), a phosphate transporter (LaPT), a MYB transcription factor, and a multi-drug toxin efflux (MATE). A genomic clone for a Pho85-like gene is presently being isolated. Promoter deletion analysis of LaAPase has been conducted to verify P responsiveness of putative cis - elements. Promoter deletions were generated through PCR and ligated into the polylinker upstream of the GUS reporter gene in plasmid pBI101.2. The resulting promoter::GUS reporter constructs were transferred to A. tumefaciens and used to transform Arabidopsis via the floral dip method. Six different LaAP::GUS constructs (each differing by 300 base pairs) have been analyzed. A region of the LaAP promoter between –1081 and –702 was required for P-deficiency specific reporter gene activity. Further deletion analysis of that region of the promoter will be conducted to isolate a minimal motif that confers expression of the reporter gene in the –P condition. Also, promoter fidelity in white lupin hairy roots will be confirmed by transformation with promoter reporter genes via Agrobacterium rhizogenes . Similar promoter deletion experiments will be performed with the 5’-upstream putative reporter region of the Pho85-like gene.