Plant & Animal Genomes XI Conference

January 11-15, 2003
Town & Country Convention Center
San Diego, CA

Workshop: Barley
            

MICROARRAY ANALYSIS OF TRANSCRIPT ABUNDANCE IN BARLEY UNDER CONDITIONS OF WATER DEFICIT

¹ Department of Agroenvironmental Science and Technology, University of Bologna, Bologna, Italy.

² TUBITAK, Marmara Research Center, Research Institute for Genetic Engineering and Biotechnology, 41470 Gebze/Kocaeli, Turkey

³ Departments of Plant Biology and of Crop Sciences, University of Illinois, Urbana, IL 61801, USA.

Microarray analysis offers interesting opportunities to unravel the molecular basis of adaptation to drought. Our goals are (i) to identify barley EST clones expressed under a wide range of drought treatments and (ii) to map the most interesting EST clones and verify their coincidence with that of major QTLs controlling yield and other agronomically relevant traits in drought stressed barley. In the first experiment, a microarray containing 1463 EST clones was used to compare the changes in transcript profiles of young plants (cv. Tokak) exposed to sudden episodes of water deficit and salinity. Drought and salinity affected largely different sets of transcripts. In the second experiment, the results obtained using samples collected from plants of Tadmor and Er/Apm exposed to a fast (ca. 8 hours) dehydration treatment were compared with those obtained following a much slower (ca. 7 days) dehydration treatment applied to plants grown in pots. Leaf samples were collected at increasingly higher stress intensities, measured as soil moisture content, relative water content and ABA concentration. The correlation of the fold-change variation in expression profiles observed in the rapid (shock) and slow dehydration treatments was significant but low (r values from 0.24 to 0.41). These results indicate that changes in expression profiles vary considerably according to the dynamics of the dehydration episode. To further investigate this issue, the results of the second experiment will be compared with those obtained in a third experiment using RNA samples of Tadmor and Er/Apm plants which have been grown directly in a soil glasshouse under well-watered and drought stressed conditions. In the meantime, we have started mapping a number of the EST clones which have shown similar responses under conditions of rapid (shock) and slow dehydration.