Analysis Of CBL10 Gene Duplication In The Halophyte Eutrema salsugineum

Persistent Link:
http://hdl.handle.net/10150/338681
Title:
Analysis Of CBL10 Gene Duplication In The Halophyte Eutrema salsugineum
Author:
Magness, Courtney A.
Issue Date:
2014
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 buildup of salt in soils is a major abiotic stress that affects agricultural productivity, limiting the growth and yield of most crop species which cannot tolerate even modest levels of salinity (glycophytes). Genetic variability for salt tolerance exists as some plants (halophytes) have adapted to environments with high levels of salt. Understanding how salt tolerance has been acquired in halophytic species will be an important part of strategies to improve the ability of crops to grow in saline soils. The CALCINEURIN B-LIKE10 (AtCBL10) calcium sensor was identified as a component of salt signaling in the glycophyte Arabidopsis thaliana (A. thaliana) based on hypersensitivity of the Atcbl10 mutant to salt. When A. thaliana is grown in the presence of salt, AtCBL10 interacts with the AtSOS2 protein kinase to activate the AtSOS1 sodium/proton exchanger, resulting in the removal of sodium ions from the cytosol. Eutrema salsugineum (E. salsugineum), a halophytic relative of A. thaliana, has two CBL10 genes (EsCBL10a and EsCBL10b). In this research, the duplication of CBL10 in E. salsugineum was characterized and the functions of EsCBL10a and EsCBL10b in salt tolerance were determined. My analyses indicate that the coding sequences of EsCBL10a and EsCBL10b are highly conserved, as they share 85% nucleotide identity. An analysis of transcript structure indicates transcripts from EsCBL10a and EsCBL10b loci are alternatively spliced, but in distinct ways. My results suggest that EsCBL10a and AtCBL10 likely share the ancestral genomic position, while EsCBL10b might have moved to a different genomic region, and that the duplication took place prior to the divergence of expanded Lineage II species. The expression patterns of EsCBL10a and EsCBL10b are different; EsCBL10b transcript is high in shoots and low in roots while EsCBL10a transcript is detectable in both tissues. Preliminary analysis of E. salsugineum lines with reduced expression of EsCBL10a and EsCBL10b suggest that both genes might play a role during growth in the presence of salt, but that these roles are distinct.
Type:
text; Electronic Thesis
Keywords:
Calcium sensor; CBL10; Gene duplication; Plant science; Salt tolerance; Plant Science; Brassicaceae
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Graduate College; Plant Science
Degree Grantor:
University of Arizona
Advisor:
Schumaker, Karen S.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleAnalysis Of CBL10 Gene Duplication In The Halophyte Eutrema salsugineumen_US
dc.creatorMagness, Courtney A.en_US
dc.contributor.authorMagness, Courtney A.en_US
dc.date.issued2014-
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 buildup of salt in soils is a major abiotic stress that affects agricultural productivity, limiting the growth and yield of most crop species which cannot tolerate even modest levels of salinity (glycophytes). Genetic variability for salt tolerance exists as some plants (halophytes) have adapted to environments with high levels of salt. Understanding how salt tolerance has been acquired in halophytic species will be an important part of strategies to improve the ability of crops to grow in saline soils. The CALCINEURIN B-LIKE10 (AtCBL10) calcium sensor was identified as a component of salt signaling in the glycophyte Arabidopsis thaliana (A. thaliana) based on hypersensitivity of the Atcbl10 mutant to salt. When A. thaliana is grown in the presence of salt, AtCBL10 interacts with the AtSOS2 protein kinase to activate the AtSOS1 sodium/proton exchanger, resulting in the removal of sodium ions from the cytosol. Eutrema salsugineum (E. salsugineum), a halophytic relative of A. thaliana, has two CBL10 genes (EsCBL10a and EsCBL10b). In this research, the duplication of CBL10 in E. salsugineum was characterized and the functions of EsCBL10a and EsCBL10b in salt tolerance were determined. My analyses indicate that the coding sequences of EsCBL10a and EsCBL10b are highly conserved, as they share 85% nucleotide identity. An analysis of transcript structure indicates transcripts from EsCBL10a and EsCBL10b loci are alternatively spliced, but in distinct ways. My results suggest that EsCBL10a and AtCBL10 likely share the ancestral genomic position, while EsCBL10b might have moved to a different genomic region, and that the duplication took place prior to the divergence of expanded Lineage II species. The expression patterns of EsCBL10a and EsCBL10b are different; EsCBL10b transcript is high in shoots and low in roots while EsCBL10a transcript is detectable in both tissues. Preliminary analysis of E. salsugineum lines with reduced expression of EsCBL10a and EsCBL10b suggest that both genes might play a role during growth in the presence of salt, but that these roles are distinct.en_US
dc.typetexten
dc.typeElectronic Thesisen
dc.subjectCalcium sensoren_US
dc.subjectCBL10en_US
dc.subjectGene duplicationen_US
dc.subjectPlant scienceen_US
dc.subjectSalt toleranceen_US
dc.subjectPlant Scienceen_US
dc.subjectBrassicaceaeen_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePlant Scienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSchumaker, Karen S.en_US
dc.contributor.committeememberSchumaker, Karen S.en_US
dc.contributor.committeememberBeilstein, Mark A.en_US
dc.contributor.committeememberYadegari, Raminen_US
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