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dc.contributor.authorHolt, Sarah Hudsonen_US
dc.date.accessioned2017-04-06T15:44:02Z
dc.date.available2017-04-06T15:44:02Z
dc.date.issued2011-09-02en_US
dc.identifier.otheretd-10032011-155130en_US
dc.identifier.urihttp://hdl.handle.net/10919/77236
dc.description.abstractThe diploid woodland strawberry (Fragaria vesca) is a rapidly developing translational model for members of the family Rosaceae and other plants. This thesis represents some of the first forward genetics studies evaluating putative T-DNA insertional mutants in F. vesca. The observed phenotypes include alterations to floral development, anthocyanin pigmentation and leaf structure. The floral development mutant named green petal (gp) was not associated with the T-DNA insertions present. Based on similar phenotypes induced by mutation of transcription factors involved in floral development of Arabidopsis thaliana, we used a BLAST search of the F. vesca genome hybrid gene models to identify 30 candidate genes that may have caused the gp phenotype. Expression analysis of these genes revealed that it was due to a 37 bp deletion in a SEPALLATA3-like E-Class MADS box transcription factor. This mutation altered organ structure in the three inner whorls of the flower, affecting fertility and fruit development. The deletion was demonstrated to segregate with the mutant phenotype in a segregating population of 92 individuals, 22 of which had green petals. The anthocyanin biosynthesis mutant named white runner (wr) lacked red pigmentation in the stems and runners. The T-DNA insertion in this line was located in a highly repetitive LTR retrotransposon region, which complicated analysis. Segregation analysis of the wr lines revealed that the phenotype was unassociated with the T-DNA insertion as well. We used a targeted expression analysis of three critical structural genes in the flavonoid biosynthesis pathway that revealed a 20 bp deletion in the gene encoding flavanone 3-hydroxylase, an enzyme necessary for the production of flavonols, anthocyanins and proanthocyanidins. In an F2 segregating population, this deletion co-segregated with the phenotype. The third mutant line presented here displayed a curly leaf (cl) phenotype and was found to harbor a T-DNA insertion in a gene encoding a putative erythroblast macrophage attacher protein (EMP). Sequence and protein domain analysis indicated that FvEMP was related to the mammalian EMP protein that functions in cytoskeletal dynamics and red blood cell enucleation. Complementation analysis confirmed that introduction of the wild type FvEMP gene into the cl mutant plants restored wild type leaf phenotype. Further morphological analysis revealed additional pleiotropic effects of the mutation, including abnormalities in seed set and germination, pollen tube growth, adhesion of the abaxial epidermal layer to the mesophyll layer and reduced petiolule length. These phenotypes are consistent with actin binding and microtubule associated protein mutants in other plant species. Insertional mutagenesis is a critical molecular tool for model crop development. These studies highlight the precautions that must be taken when evaluating insertional mutants. These mutants are excellent tools for studying their respective disrupted gene function. The in depth molecular analysis of the mutants presented in this work was only possible because of the availability of the Fragaria vesca genome which was used extensively to identify T-DNA insertion sites and recover candidate gene sequences for expression analysis.
dc.language.isoen_USen_US
dc.publisherVirginia Techen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectF3Hen_US
dc.subjectRosaceaeen_US
dc.subjectT-DNAen_US
dc.subjectSEPALLATAen_US
dc.subjectSomaclonal variationen_US
dc.subjectEMPen_US
dc.titleGenetic studies of phenotypic variants in the woodland strawberry, (Fragaria vesca)en_US
dc.typeDissertationen_US
dc.contributor.departmentHorticultureen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineHorticultureen_US
dc.contributor.committeechairVeilleux, Richard E.en_US
dc.contributor.committeememberTokuhisa, James G.en_US
dc.contributor.committeememberWinkel, Brenda S. J.en_US
dc.type.dcmitypeTexten_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10032011-155130/en_US
dc.contributor.committeecochairShulaev, Vladimiren_US
dc.contributor.committeecochairDan, Yinghuien_US
dc.date.sdate2011-10-03en_US
dc.date.rdate2016-09-30
dc.date.adate2011-10-24en_US


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