Department of Biology, University of Northern Iowa, Cedar Falls, IA 50614, USA.
Funct Integr Genomics. 2010 May;10(2):191-205. doi: 10.1007/s10142-009-0149-4. Epub 2009 Nov 20.
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.
大麦穗（外稃、内稃和芒）的光合作用器官被认为具有抗旱性。然而，关于干旱条件下穗器官基因表达的信息却很少。我们使用大麦 1 号基因组芯片比较了在灌浆期（籽粒灌浆期）通过断水处理 4 天后，外稃、内稃、芒和种子对干旱胁迫的转录组反应。在胁迫结束时，外稃、内稃和芒的相对含水量从 85%下降到 60%。然而，种子的含水量仅从 89%下降到 81%。转录丰度随穗器官的水分状况而变化；与内稃和外稃相比，芒具有更多的干旱调节基因，而种子的基因表达变化很小。尽管芒表达了更多与干旱相关的基因，但与内稃、外稃和种子相比，许多参与氨基酸、氨基酸衍生物和碳水化合物代谢以及光合作用、呼吸和应激反应的基因下调。这表明与芒相比，外稃和内稃对干旱胁迫更具抗性。
