Original Paper

Functional & Integrative Genomics

, Volume 10, Issue 2, pp 191-205

First online:

Drought response in the spikes of barley: gene expression in the lemma, palea, awn, and seed

  • Tilahun AbebeAffiliated withDepartment of Biology, University of Northern Iowa Email author 
  • , Kalpalatha MelmaieeAffiliated withDepartment of Biology, University of Northern IowaPMGG Lab, Department of Agricultural and Natural Resources, Delaware State University
  • , Virginia BergAffiliated withDepartment of Biology, University of Northern Iowa
  • , Roger P. WiseAffiliated withCorn Insects and Crop Genetics Research, USDA/ARS and Department of Plant Pathology, Iowa State University

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The photosynthetic organs of the barley spike (lemma, palea, and awn) are considered resistant to drought. However, there is little information about gene expression in the spike organs under drought conditions. We compared response of the transcriptome of the lemma, palea, awn, and seed to drought stress using the Barley1 Genome Array. Barley plants were exposed to drought treatment for 4 days at the grain-filling stage by withholding water. At the end of the stress, relative water content of the lemma, palea, and awn dropped from 85% to 60%. Nevertheless, the water content of the seed only decreased from 89% to 81%. Transcript abundance followed the water status of the spike organs; the awn had more drought-regulated genes followed by lemma and palea, and the seed showed very little change in gene expression. Despite expressing more drought-associated genes, many genes for amino acid, amino acid derivative, and carbohydrate metabolism, as well as for photosynthesis, respiration, and stress response, were down-regulated in the awn compared with the lemma, palea, and seed. This suggests that the lemma and the palea are more resistant to drought stress compared with the awn.


Awn Drought Lemma Palea Seed Transcriptome