Poster: Regulation of gene expression

Abs # 741: Impact of P and K nutrition on alfalfa (Medicago sativa L.) taproot gene expression and plant growth and survival.

Presenter:	Cunningham, Suzanne M., scunningham@purdue.edu
Authors	Cunningham, Suzanne M. (A)   Berg, William K. (A)   Volenec, Jeffrey J. (A)
Affiliations:	(A): Agronomy Dept., Purdue University

Fertilization of alfalfa with P and K enhances growth and plant survival, but imbalanced nutrition may be more detrimental than deprivation of both nutrients. During the summers of 2002 and 2003, extensive plant death occurred in plots fertilized with P but not K, while survival was excellent in plots fertilized with 200 kg K/ha/yr with P or in plants left unfertilized. Our objective was to determine how gene expression was altered in roots of alfalfa provided contrasting P and K nutrition. Total RNA was extracted from roots in May 2002 and 2003 and in December 2002, and differential display was used to ascertain the impact of P and K nutrition on transcript abundance. Bands were eluted from the dd gels, amplified, and ligated to the pGEM vector. Dot blotting was used to initially verify cDNAs that are differentially transcribed. Final comparisons of differential DNA expression will be done using Northern blots containing RNA collected in May and December of 2002 and 2003. The cDNA inserts will be sequenced, and full-length clones will be obtained by screening cDNA libraries.