Functional and Evolutionary Analysis of Cation/Proton Antiporter-1 Genes in Brassicaceae Adaptation to Salinity

Persistent Link:
http://hdl.handle.net/10150/312652
Title:
Functional and Evolutionary Analysis of Cation/Proton Antiporter-1 Genes in Brassicaceae Adaptation to Salinity
Author:
Jarvis, David
Issue Date:
2013
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The accumulation of salts in soil is an important agricultural problem that limits crop productivity. Salts containing sodium (Na⁺) are particularly problematic, as cytosolic Na⁺ can interfere with cellular metabolism and lead to cell death. Maintaining low levels of cytosolic Na⁺, therefore, is critical for plant survival during growth in salt. Mechanisms to regulate Na⁺ accumulation in plant cells include extrusion of Na⁺ from the cell and sequestration of Na⁺ into intracellular compartments. Both of these processes are controlled in part through the action of Na⁺/H⁺ exchangers belonging to the Cation/Proton Antiporter-1 (CPA1) gene family. Genes belonging to this family have been identified in both salt-sensitive and salt-tolerant species, suggesting that salt-tolerant species may have evolved salt tolerance through modification of these existing pathways. The research presented here has focused on understanding how salt tolerance has evolved in Brassicaceae species, and particularly on the role that CPA1 genes have played in the adaptation to salinity of Eutrema salsugineum. Specific projects have sought to understand 1) how copy number variation and changes in coding sequences of CPA1 genes contribute to salt tolerance in E. salsugineum and its salt-tolerant relative Schrenkiella parvula, 2) whether functional or regulatory changes in Salt Overly Sensitive 1 (SOS1) from E. salsugineum (EsSOS1) contribute to its enhanced salt tolerance, and 3) whether accessions of Arabidopsis thaliana differ significantly in their response to salt stress.The results indicate that EsSOS1 and SOS1 from S. parvula (SpSOS1) both confer greater salt tolerance in yeast than SOS1 from A. thaliana (AtSOS1) when activated by the complex of the SOS2 kinase and SOS3 calcium-binding protein, whereas only EsSOS1 confers enhanced salt tolerance in the absence of activation. When expressed in A. thaliana, EsSOS1 also confers greater salt tolerance than AtSOS1 through regulatory changes that likely involve differences in expression pattern. Together, the results presented here suggest that mechanisms regulating cellular Na⁺ accumulation that exist in salt-sensitive crop species could be altered to enhance growth in salty soils. In addition, the 19 A. thaliana accessions used to create the MAGIC population were shown to differ significantly in their response to salt stress.
Type:
text; Electronic Dissertation
Keywords:
CPA1; Eutrema salsugineum; Salt tolerance; SOS1; Plant Science; Brassicaceae
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Plant Science
Degree Grantor:
University of Arizona
Advisor:
Schumaker, Karen

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleFunctional and Evolutionary Analysis of Cation/Proton Antiporter-1 Genes in Brassicaceae Adaptation to Salinityen_US
dc.creatorJarvis, Daviden_US
dc.contributor.authorJarvis, Daviden_US
dc.date.issued2013en
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe accumulation of salts in soil is an important agricultural problem that limits crop productivity. Salts containing sodium (Na⁺) are particularly problematic, as cytosolic Na⁺ can interfere with cellular metabolism and lead to cell death. Maintaining low levels of cytosolic Na⁺, therefore, is critical for plant survival during growth in salt. Mechanisms to regulate Na⁺ accumulation in plant cells include extrusion of Na⁺ from the cell and sequestration of Na⁺ into intracellular compartments. Both of these processes are controlled in part through the action of Na⁺/H⁺ exchangers belonging to the Cation/Proton Antiporter-1 (CPA1) gene family. Genes belonging to this family have been identified in both salt-sensitive and salt-tolerant species, suggesting that salt-tolerant species may have evolved salt tolerance through modification of these existing pathways. The research presented here has focused on understanding how salt tolerance has evolved in Brassicaceae species, and particularly on the role that CPA1 genes have played in the adaptation to salinity of Eutrema salsugineum. Specific projects have sought to understand 1) how copy number variation and changes in coding sequences of CPA1 genes contribute to salt tolerance in E. salsugineum and its salt-tolerant relative Schrenkiella parvula, 2) whether functional or regulatory changes in Salt Overly Sensitive 1 (SOS1) from E. salsugineum (EsSOS1) contribute to its enhanced salt tolerance, and 3) whether accessions of Arabidopsis thaliana differ significantly in their response to salt stress.The results indicate that EsSOS1 and SOS1 from S. parvula (SpSOS1) both confer greater salt tolerance in yeast than SOS1 from A. thaliana (AtSOS1) when activated by the complex of the SOS2 kinase and SOS3 calcium-binding protein, whereas only EsSOS1 confers enhanced salt tolerance in the absence of activation. When expressed in A. thaliana, EsSOS1 also confers greater salt tolerance than AtSOS1 through regulatory changes that likely involve differences in expression pattern. Together, the results presented here suggest that mechanisms regulating cellular Na⁺ accumulation that exist in salt-sensitive crop species could be altered to enhance growth in salty soils. In addition, the 19 A. thaliana accessions used to create the MAGIC population were shown to differ significantly in their response to salt stress.en_US
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectCPA1en_US
dc.subjectEutrema salsugineumen_US
dc.subjectSalt toleranceen_US
dc.subjectSOS1en_US
dc.subjectPlant Scienceen_US
dc.subjectBrassicaceaeen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePlant Scienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSchumaker, Karenen_US
dc.contributor.committeememberSchumaker, Karenen_US
dc.contributor.committeememberBeilstein, Marken_US
dc.contributor.committeememberPalanivelu, Ravien_US
dc.contributor.committeememberTax, Fransen_US
dc.contributor.committeememberWang, Xiangfengen_US
dc.contributor.committeememberYadegari, Raminen_US
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