Plant & Animal Genome VII Conference

P35

CLONING, CHARACTERIZATION AND MAPPING OF RIBOSOMAL RNA GENES IN Plantago.

¹Wheat Genetics Resource Center, Department of Plant Pathology, Kansas State University, 4024 Throckmorton Plant Sciences Center, Manhattan, KS 66506-5502 USA

² Permanent address: Department of Botany, University of Jammu, Jammu - 180 006, J & K, India

Ribosomal DNA variations have been widely described in many plant species. These genes are arranged in tandem arrays, generally associated with nucleolus organizing regions (NORs). Each array is composed of a coding sequence and an intergenic spacer. While the coding regions are conserved, the spacer regions show lot of variability both in terms of size as well as sequence. The Genus Plantago (Plantaginaceae) is comprised of about 280 species. The genus is known because of one species, P. ovata, whose seed husk yields Isabgol (blond psyllium) of commerce. Besides being a highly effective laxative, Isabgol has recently been used in lowering blood cholesterol levels. So far, there is hardly any report on molecular studies in this genus. As a first step in this direction, we have analyzed the organization of rRNA genes in cultivated P. ovata and several of its wild allies. Specific primers were designed to amplify specifically the Internal Transcribed Spacer (ITS1 and ITS2) regions, which were cloned and sequenced. Similarly, the genes coding for 5S rRNA were cloned and sequenced. While sequence comparison shows similarity of these genes with other species, there are some differences. We have also mapped these genes on chromosomes using FISH technique.