Proceedings of the XLV Italian Society of Agricultural Genetics - SIGA Annual Congress

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Oral Communication Abstract

SRG6, A PUTATIVE STRESS REGULATED TRANSCRIPTION FACTOR-LIKE GENE IN BARLEY

MALATRASI M.*^,**, CLOSE T.J.**

* Sez.Genetica e Biotecnologie Ambientali, Dip. Scienze Ambientali, Università di Parma

malatras@dsa.unipr.it

** Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521-0124 USA

timothy.close@ucr.edu

barley, ABA, drought, transcription factor, DDRT-PCR

Crop productivity is restricted by multiple abiotic stress conditions such as high soil salinity, chilling, freezing, heat and drought. Among these, drought is one of the major limiting factors. The plant hormone abscisic acid (ABA) regulates several physiological and developmental processes in plants, including stress adaptation and seed maturation. An increase of ABA levels is responsible for the induction of many genes and presumably some of these are involved in the development of drought tolerance. The mechanisms that regulate all the cascade of events are not yet well understood. It seems that many regulatory elements are involved in the regulation of the expression of stress-induced genes. A correlation between accumulation of specific proteins and drought adaptation in different plants it has been reported. Therefore the isolation and characterization of genes that are downregulated and upregulated by water stress have been used as a strategy for studying plant response to drought, and to elucidate the metabolic events that protect plants from drought.

A differential display approach was used in barley to identify novel genes that show changes in the expression level during drought, cold and ABA treatments. This technique offers the possibility of identifying low copy number messengers, with the simultaneous comparison of several stress conditions. Several novel cDNA fragments have been isolated. In this work we have focused our attention on a 225 bp fragment named DD6 isolated in drought condition. Northern blot assay has shown that the quantity of DD6 transcript increased during ABA treatment and under water deficit conditions. The full length of DD6 transcript (designated Srg6: Stress Responsive Gene) is about 1.7 kb. By 5'-RACE (Rapid Amplification of cDNA Ends) an extended cDNA from DD6 was obtained. Thereafter, from the screening of a barley BAC library the corresponding gene was isolated, and the sequences of transcribed and flanking regions were determinated. The Srg6 gene is composed of 11 exons, and has an ORF of 1140 bp corresponding to a protein of 379 amino acids with a deduced size of 43.3 kDa. SRG6 is homologous to a hypothetical protein of Arabidopsis and to the human and mouse YL-1 transcription factor-like protein. Using two double haploid barley mapping populations, Srg6 was mapped on the short arm of chromosome 7H, a region important in the regulation of osmotic adaptation.