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United States Department of Agriculture

Agricultural Research Service

Title: Identification of Dehydration Responsive Genes from Two Non-Nodulated Alfalfa Cultivars Using Medicago Truncatula Microarrays)

Author
item Chen, Dong
item Liang, Ming
item Dewald, Daryll
item Weimer, Bart
item Peel, Michael
item Bugbee, Bruce
item Michaelson, Jacob
item Davis, Elizabeth
item Wu, Yajun

Submitted to: Acta Physiologiae Plantarum
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/19/2007
Publication Date: 10/19/2007
Citation: Chen, D., Liang, M.X., Dewald, D., Weimer, B., Peel, M., Bugbee, B., Michaelson, J., Davis, E., Wu, Y. 2008. Identification of Dehydration Responsive Genes from Two Non-Nodulated Alfalfa Cultivars Using Medicago Truncatula Microarrays. Acta Physiologiae Plantarum 30:183-199

Interpretive Summary: To have a comprehensive understanding of how legume plants respond to drought at the gene expression level and examine whether legume plants that are not fixing nitrogen would behave similar to non-legume plants in drought response, transcriptomes were studied in two non-nodulated alfalfa (Medicago sativa L.) cultivars, Ladak and 53V08, when plants were subjected to dehydration stress. Two heat shock-related protein genes were up-regulated in the 3-h stressed shoots in both cultivars. One of them was also up-regulated in the 8-h stressed shoots, along with dehydrin and LEA. A xyloglucan endotransglycosylase and a gene with unknown function were down-regulated in both 3- and 8-h stressed shoots. In roots, nearly half of the 55 genes commonly up-regulated at 3 h are involved in pathogen resistance, insect defense and flavonoid synthesis, which differs from other dehydration - responsive transcriptomes in the literature. Many known drought-responsive genes, such as LEA and dehydrin, 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, while two aquaporin genes were down-regulated, suggesting that lignification and prevention of water loss in roots in initial dehydration stress is a common strategy for both cultivars. The results also indicate the involvement of some specific signal transduction pathways, osmotic adjustment and ion homeostasis regulation during dehydration response. Besides those known dehydration - responsive genes in the literature, some dehydration responses and genes in alfalfa appear to be unique. Our results provide valuable insight into a comprehensive understanding of dehydration response in alfalfa at the molecular level. Electronic supplementary material: The online version of this article (doi:10.1007/s11738-007-0107-5) contains supplementary material, which is available to authorized users.

Technical Abstract: To have a comprehensive understanding of how legume plants respond to drought at the gene expression level and examine whether legume plants that are not fixing nitrogen would behave similar to non-legume plants in drought response, transcriptomes were studied in two non-nodulated alfalfa (Medicago sativa L.) cultivars, Ladak and 53V08, when plants were subjected to dehydration stress. Two heat shock-related protein genes were up-regulated in the 3-h stressed shoots in both cultivars. One of them was also up-regulated in the 8-h stressed shoots, along with dehydrin and LEA. A xyloglucan endotransglycosylase and a gene with unknown function were down-regulated in both 3- and 8-h stressed shoots. In roots, nearly half of the 55 genes commonly up-regulated at 3 h are involved in pathogen resistance, insect defense and flavonoid synthesis, which differs from other dehydration - responsive genes, such as LEA and dehydrin, 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, while two aquaporin genes were down-regulated, suggesting that lignification and prevention of water loss in roots in initial dehydration stress is a common strategy for both cultivars. The results also indicate the involvement of some specific signal transduction pathways, osmotic adjustment and ion homoeostasis regulation during dehydration response. Besides those known dehydration - responsive genes in the literature, some dehydration responses and genes in alfalfa appear to be unique. Our results provide valuable insight into a comprehensive understanding of dehydration response in alfalfa at the molecular level. Electronic supplementary material: The online version of this article (doi:10.1007/s11738-007-0l07.5) contains supplementary material, which is available to authorized users.

Last Modified: 8/24/2016
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