Transcriptional analysis of a CAR gene family from Medicago ativa
Dr. J.Ache Gana

Dr. J. Ache Gana
Department of Biological Sciences

The plant species, alfalfa (Medicago sativa) is an important crop with diverse uses, but its productivity is severely limited by abiotic stresses.  Alfalfa is the most important feed for dairy cattle and other farm animals because it provides a high source of protein.  The crop is increasingly consumed by humans as a valuable source of soluble protein, vitamins A, C, E, and K, antioxidant, and phytoestrogens and used as a medicinal herb in prevention of diseases such as osteoporosis, cancer, heart disease, menopausal symptoms, and symptomatic arthritis.  Further, alfalfa is being exploited in biofarming for the production of vaccines and other industrial enzymes, and in bioremediation of contaminated soil and ground water.

Although the alfalfa crop is economically significant, it is the least researched among the important crop species.  Abiotic stresses, in particular freeze stress, greatly reduce productivity of alfalfa.  Our long-term goal is to understand the fundamental mechanisms of freeze tolerance in alfalfa.  The proposed experiments are designed to understand further the mechanisms of freeze tolerance by studying the transcriptional regulatory sequences of a cold acclimation responsive gene family (CAR), whose expression correlates with freeze tolerance.  It appears that some aspects of alfalfa freeze tolerance mechanisms may have diverged uniquely from those of Arabidopsis because this gene family has no orthologs in the genome of the Arabidopsis plant model species.  The experiments proposed will investigate the regulatory elements upstream from CAR transcribed sequences, determine promoter inducible response by different stresses, map regulatory elements imparting the maximum cold inducible response, determine the affinities of specific CAR regulatory element to proteins in cell extracts of freeze tolerant and freeze susceptible alfalfas, and define the spatial CAR expression. 

The information gained from these studies will include identification of specific regulatory sequences contributing to alfalfa freeze tolerance, delineation of the stress tolerance pathway that triggers CAR gene expression, and contribution to the general understanding of eukaryotic transcriptional gene regulation mechanisms.  A comprehensive picture of the molecular dynamics of abiotic stress tolerance is of basic scientific interest and has potential practical applications.  For example, variety enhancement of the freeze tolerant trait to increase alfalfa productivity should impact animal and human nutrition, medicine, and bioremediation.

Graduate student Angenee Milton and project technician Denise Patrick

Graduate student Angenee Milton (left) and project
technician Denise Patrick working in Dr. Gana's lab. ab.

Recent Presentations

Angenee Milton, S. M. Cunningham, J. J. Volenec, J. A.  Gana: HETEROGENEOUS TRANSCRIPTION START SITES IN ALFALFA (MEDICAGO SATIVA L.) ROOTCAR1 PROMOTER  IN RESPONSE TO COLD STRESS, 19th Annual Illinois Alliance for Minority Participation (AMP) Student Research Conference, Glenview, IL, October 6-7, 2006

Ikenna Madueke, Denise J. Patrick and Joyce Ache Gana, CHARACTERIZATION OF THE FULL-LENGTHROOTCAR1 PROMOTER IN ALFALFA MESOPHYLL PROTOPLASTS IN RESPONSE TO EXOGENOUS ABSCISIC ACID, 19th Annual Illinois Alliance for Minority Participation (AMP) Student Research Conference, Glenview, IL, October 6-7, 2006

Pamela Ihonor, Emlah Yosimbom, Denise J. Patrick and Joyce Ache Gana, CELLULAR LOCALIZATION OF b-AMYLASE IN BARK TISSUES OF ALFALFA TAPROOTS 19th Annual Illinois Alliance for Minority Participation (AMP) Student Research Conference, Glenview, IL, October 6-7, 2006

Milton, R. N. Singa1, S. M. Cunningham, J. A. Gana, W. K. Berg, and J. J. Volenec (2005) Cold-acclimation Responsive Gene Promoter inMedicago sativa Reveals Polymorphism, G-Box Elements, and Allele Shifts in Freeze Susceptible and Tolerant Populations.  Gordon Research Conference: Temperature Stress In Plants. 2004.  Ventura, CA

Milton J, Gana JA  ( 2005)  Do dual TATA elements inRootCAR1 promoter function as alternate transcription start sites in alfalfa (Medicago sativa L.)?  Midwest American Society of Plant Biologists Sectional Meeting.  March 18-19.  St. Louis, MO

Quaye L., Gana JA  (2005) Characterization of the expression pattern of the cold acclimation response gene,RootCAR1, to exogenous ABA, cold, dehydration, and salt in seedlings of alfalfa (Medicago sativa L.).  Midwest American Society of Plant Biologists Sectional Meeting.  March 18-19.  St. Louis, MO * Singa P, Gana JA (2005) Promoter inducible response of RootCAR1, a cold acclimation response gene in alfalfa (Medicago sativa L.) using protoplast transient assays. Midwest American Society of Plant Biologists Sectional Meeting.  March 18-19.  St. Louis, MO

Yosimbom E, Gana JA (2005) Comparison of amyloplast structure and numbers in mature intact and defoliated alfalfa plants (Medicago sativa L.) by transmission electron microscopy. Midwest American Society of Plant Biologists Sectional Meeting.  March 18-19.  St. Louis, MO

Wakefield Noelle, Akatsa I, Gana JA (2005) Promoter identification of alfalfa (Medicago sativa L.) amylase gene. Midwest American Society of Plant Biologists Sectional Meeting.  March 18-19.  St. Louis, MO

Noelle Wakefield presenting her research at the 2004 ABRCMS, Dallas, TX, 2004

RISE Program student Noelle Wakefield (right) presenting her summer
research at the ABRCMS meeting, Dallas, TX, November 2004.

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This page was last updated on 10/26/06