Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Genetic And Morphological Characterization Of The Reduced Tillering Barley Mutant uniculm4 (Cul4)

HATICE BILGIC , Seungho Cho , Gary J. Muehlbauer

  Department of Agronomy and Plant Genetics University of Minnesota 411 Borlaug Hall, 1991 Upper Buford Circle St. Paul, MN 55108

Axillary meristem (AXM) and tiller development determine plant architecture in barley (Hordeum vulgare L.). To gain an understanding of AXM development and tillering, we are examining the low tillering barley uniculm4 (cul4) mutants. Plants carrying the recessive cul4 mutation develop one to four tillers. Histological and scanning electron microscopy analyses of cul4 mutant plants showed that multiple AXM were formed in the same leaf axil but that these AXM do not always develop into tillers. Double mutant combinations of cul4 and eight other recessive mutations that exhibit either higher or lower number of tillers, resulted in a low tillering, cul4 vegetative phenotype, indicating that cul4 is epistatic to these mutants. The inflorescence phenotypes of the double mutants were either similar to that of the second barley mutant, indicating an epistatic interaction, or showing similarities to inflorescence phenotypes of both single mutants, indicating an additive interaction.
Our results demonstrate that the CUL4 gene product functions to regulate the number of AXM per leaf axil, and tiller and inflorescence development. We also used the Barley1 GeneChip to examine the transcript accumulation differences between cul4 mutants and wild-type. A description of the GeneChip analysis will be presented. Finally, we positioned the cul4 gene on the distal end of the long arm of chromosome 3(3H).