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United States Department of Agriculture

Agricultural Research Service

Title: Identification of Drought Response Genes fom Two Alfalfa Cultivars Using Medicago Truncatula Microarrays

Authors
item Chen, Dong - UTAH STATE UNIVERSITY
item Liang, Ming-Xiang - UTAH STATE UNIVERSITY
item Dewald, Daryll - UTAH STATE UNIVERSITY
item Peel, Michael
item Bugbee, Bruce - UTAH STATE UNIVERSITY
item Michaelson, Jacob - UTAH STATE UNIVERSITY
item Davis, Elizabeth - UTAH STATE UNIVERSITY
item Wu, Yajun - UTAH STATE UNIVERSITY

Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 19, 2007
Publication Date: October 19, 2007
Citation: Chen, D., Liang, M., Dewald, D., Peel, M., Bugbee, B., Michaelson, J., Davis, E., Wu, Y. 2007. Identification of Drought Response Genes fom Two Alfalfa Cultivars Using Medicago Truncatula Microarrays. Plant Molecular Biology.

Interpretive Summary: As the first step to identify drought-responsive genes in alfalfa (Medicago sativa L.) and understand how nitrogen fixation interacts with drought response in plants, transcriptomes were studied in two cultivars, Ladak and 53V08, when non-nodulated plants were subjected to drought stress. A small set of genes shared by these two cultivars were identified during drought response. Two heat shock-related protein genes were up regulated in the 3 h stressed shoots in both cultivars. One of them, an 18.2 kDa class I heat shock protein, was among several genes, including dehydrin and LEA, that were upregulated in the 8 h stressed shoots as well. The only two down regulated genes in the 3 h stressed shoots, a xyloglucan endotransglycosylase and a gene with unknown function, were also down regulated in the 8 h stressed shoots. In roots, nearly half of the 55 commonly up regulated genes at 3 h are involved in pathogen resistane, insect defense and flavonoid synthesis, while known drought-responsive genes, such as LEA and dehydrin, were upregulated after 8 h of treatment. The genes encloding caffeoyl-CoA O-methyl transferase and dirigent were up regulated in the 3 h stressed roots, along with the down regulation of two aquaporin genes in the 3 h stressed roots, suggesting that lignification and prevention of water loss in roots in initial drought stress is a common strategy for these two cultivars. The results also indicated the involvement of some specific signal transduction pathways, plant hormones, osmotic adjustment and ion homeoastasis regulation during drought response.

Technical Abstract: As the first step to identify drought-responsive genes in alfalfa (Medicago sativa L.) and understand how nitrogen fixation interacts with drought response, the alfalfa Ladak and 53V08 were studied when subjected to drought stress. A small set of genes shared by these two cultivars were identified during drought response. Two heat shock-related protein genes were up regulated in 3 hour stressed shoots of both cultivars. One of them, a heat shock protein, was among several other genes, including dehydrin and LEA, that were up regulated in shoots stress for 8 hours. The only two down regulated genes in the 3 h stressed shoots were also down regulated in the 8 h stressed shoots. In roots, nearly half of the 55 commonly up regulated genes at 3 h are involved in pathogen resistance, insect defense and flavonoid synthesis, while known drought-responsive genes were up regulated after 8 h of treatment. The genes encoding caffeoyl-CoA O-methyl transferase and dirigent were up regulated in the 3 h stressed roots, along with the down regulation of two aquaporin genes in the 3 h stressed roots, suggesting that lignification and prevention of water loss in roots in initial drought stress is a common strategy for these two cultivars. The results also indicated the involvement of some specific signal transduction pathways, plant hormones, osmotic adjustment and ion homeostasis regulation during drought response.

Last Modified: 4/19/2014
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