Genetic Studies of CLAVATA Pathway Receptor Mutants Reveal Distinctions between Pathway Components in Meristems and Fruit

Persistent Link:
http://hdl.handle.net/10150/195699
Title:
Genetic Studies of CLAVATA Pathway Receptor Mutants Reveal Distinctions between Pathway Components in Meristems and Fruit
Author:
Durbak, Amanda Rita
Issue Date:
2010
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 CLAVATA1 (CLV1), CLV2 and CORYNE (CRN) receptors egulate cell proliferation in shoot meristems through inhibition of WUSCHEL (WUS). Mutations in these receptors produce more floral organs. The prevailing model proposes that the extra organs are generated from enlarged floral meristems. Using forward and reverse genetics, I identified new alleles in clv1, clv2 and crn and found that most alleles only affect fruit organ number and not sepal, petal or stamen number. Analysis of inflorescence and floral meristems of clv1, clv2 and crn mutants revealed that most mutants do not have altered meristem size. I show that mutations in the ERECTA gene enhance the extra valve phenotype in crn mutants by increasing proliferation in floral meristems. Further data indicate that all mutants tested generate extra organs during fruit development and that CLV1, CLV2 and CRN expression in developing fruit overlaps with regions of increased cell division and extra organs formation. In addition, I provide evidence that CLV1 regulates the transcription factor SHOOTMERISTEMSLESS (STM) in these same regions, as mutations in STM suppress the fruit development phenotype in clv1 mutants.Analysis of the relationship between CLV pathway receptors in meristems and fruit revealed that during fruit development, all three are required to regulate fruit organ number. In meristems, I find that CLV1 appears to play a predominant role, based on evidence that the CLV1 homolog BARELY ANY MERISTEM1 (BAM1) compensates for the absence of CLV1 in the meristem but not in fruit. The fact that BAM1 does not interact genetically with CLV2 or CRN in meristems, further supports the hypothesis that BAM1/CLV1 receptor complexes play key roles in meristems. My analyses suggest that CLV3 acts specifically in the meristem pathway, and not in fruit. Also, I provide genetic data for a CLV3-related CLE gene as a ligand for the fruit-specific pathway. The work presented here provides evidence that a CLV/CRN-STM pathway acts in fruit to restrict cell division and consequently organ number via a mechanism analogous to the CLV/CRN-WUS pathway in shoot meristems, supporting the hypothesis that plants use conserved CLE/Receptor-like kinase/Homeodomain signaling module to maintain meristematic regions throughout the plant.
Type:
text; Electronic Dissertation
Keywords:
CLAVATA; CORYNE; fruit development; receptor like kinase
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Plant Science; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Tax, Frans E.
Committee Chair:
Tax, Frans E.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleGenetic Studies of CLAVATA Pathway Receptor Mutants Reveal Distinctions between Pathway Components in Meristems and Fruiten_US
dc.creatorDurbak, Amanda Ritaen_US
dc.contributor.authorDurbak, Amanda Ritaen_US
dc.date.issued2010en_US
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 CLAVATA1 (CLV1), CLV2 and CORYNE (CRN) receptors egulate cell proliferation in shoot meristems through inhibition of WUSCHEL (WUS). Mutations in these receptors produce more floral organs. The prevailing model proposes that the extra organs are generated from enlarged floral meristems. Using forward and reverse genetics, I identified new alleles in clv1, clv2 and crn and found that most alleles only affect fruit organ number and not sepal, petal or stamen number. Analysis of inflorescence and floral meristems of clv1, clv2 and crn mutants revealed that most mutants do not have altered meristem size. I show that mutations in the ERECTA gene enhance the extra valve phenotype in crn mutants by increasing proliferation in floral meristems. Further data indicate that all mutants tested generate extra organs during fruit development and that CLV1, CLV2 and CRN expression in developing fruit overlaps with regions of increased cell division and extra organs formation. In addition, I provide evidence that CLV1 regulates the transcription factor SHOOTMERISTEMSLESS (STM) in these same regions, as mutations in STM suppress the fruit development phenotype in clv1 mutants.Analysis of the relationship between CLV pathway receptors in meristems and fruit revealed that during fruit development, all three are required to regulate fruit organ number. In meristems, I find that CLV1 appears to play a predominant role, based on evidence that the CLV1 homolog BARELY ANY MERISTEM1 (BAM1) compensates for the absence of CLV1 in the meristem but not in fruit. The fact that BAM1 does not interact genetically with CLV2 or CRN in meristems, further supports the hypothesis that BAM1/CLV1 receptor complexes play key roles in meristems. My analyses suggest that CLV3 acts specifically in the meristem pathway, and not in fruit. Also, I provide genetic data for a CLV3-related CLE gene as a ligand for the fruit-specific pathway. The work presented here provides evidence that a CLV/CRN-STM pathway acts in fruit to restrict cell division and consequently organ number via a mechanism analogous to the CLV/CRN-WUS pathway in shoot meristems, supporting the hypothesis that plants use conserved CLE/Receptor-like kinase/Homeodomain signaling module to maintain meristematic regions throughout the plant.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectCLAVATAen_US
dc.subjectCORYNEen_US
dc.subjectfruit developmenten_US
dc.subjectreceptor like kinaseen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePlant Scienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorTax, Frans E.en_US
dc.contributor.chairTax, Frans E.en_US
dc.contributor.committeememberTax, Frans E.en_US
dc.contributor.committeememberSchumaker, Karenen_US
dc.contributor.committeememberZarnescu, Danielaen_US
dc.contributor.committeememberPalanivelu, Ravien_US
dc.contributor.committeememberYadegari, Raminen_US
dc.identifier.proquest11373en_US
dc.identifier.oclc752261237en_US
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