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Decreased dicamba transport due to increased flavonoid biosynthesis: a candidate dicamba resistance mechanism

dc.contributor.authorPettinga, Dean J., author
dc.contributor.authorGaines, Todd A., advisor
dc.contributor.authorWard, Sarah, committee member
dc.contributor.authorSloan, Daniel, committee member
dc.date.accessioned2017-01-04T22:59:20Z
dc.date.available2017-12-30T06:30:24Z
dc.date.issued2016
dc.description.abstractResistance to dicamba (a synthetic auxin herbicide) has been documented in Kochia scoparia (L.) Schrad. populations since 1994, but the molecular mechanisms of observed resistance cases remain elusive. An RNA-Seq approach was used to identify transcripts with significantly differential transcription responses between inbred lines of dicamba-resistant (9425R) and dicamba-susceptible (7710S) K. scoparia in response to dicamba application. Among the significantly differentially expressed transcripts was both Chalcone Synthase (CHS), the first enzyme and rate-limiting step in the flavonoid biosynthesis pathway, and Flavono 3'-Hydroxylase (F3'H), which catalyzes the conversion of quercetin into kaempferol, known inhibitors of auxin transport. In silico expression patterns of both transcripts were confirmed with qRT-PCR. An F2 population derived from a cross of 9425R x 7710S segregating for the resistance phenotype was assayed for CHS and F3'H expression using qRT-PCR. Dicamba-resistant F2 individuals displayed significantly higher CHS transcript abundance compared to dicamba-susceptible F2 individuals, associating the resistance phenotype of 9425R with a greater overall flux through the flavonoid biosynthesis pathway. Increased production of the auxin transport inhibitors quercetin and kaempferol could reduce intercellular transport and vascular loading of dicamba, causing a substantial reduction in dicamba efficacy by reducing its translocation to sensitive meristematic tissue, thereby conferring the observed resistance phenotype.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifier.urihttp://hdl.handle.net/10217/178933
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectchalcone synthase
dc.subjectflavonoids
dc.subjectresistance
dc.subjectdicamba
dc.subjectauxin
dc.subjectkochia
dc.titleDecreased dicamba transport due to increased flavonoid biosynthesis: a candidate dicamba resistance mechanism
dc.typeText
dcterms.embargo.expires12/30/2017
dcterms.embargo.terms12/30/2017
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineBioagricultural Sciences and Pest Management
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)

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