Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610902
Title: Context specificity of auxin response in plant development
Author: Del Bianco , Marta
Awarding Body: University of Leeds
Current Institution: University of Leeds
Date of Award: 2011
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Abstract:
The shoot apical meristem (SAM) is the source of all above ground organs in the plant. It can be divided into a central zone (CZ) and a surrounding ring region called peripheral zone (PZ). The CZ contains the stem cells, the organizing centre and undifferentiated stem cell daughters. In the peripheral zone, in response to auxin accumulation, cells begin to differentiate to give rise to lateral organs. Application of auxin to other parts of the SAM does not lead to the formation of leaves or flowers and, in fact, the CZ seems to be insensitive to auxin. These differences in responsiveness and output in the meristem zones can be attributed to differences in the auxin signalling network. To allow the identification and sampling of small and inaccessible tissues such as the meristem zones, protocols for the use of fluorescent and histochemical markers to guide Laser Capture Microdissection were developed. These new methods allowed the precise capture of specific plant cell-types in a manner that was compatible with subsequent extraction and amplification of RNA for RNA-Seq analysis. These novel tools together represent a valuable technology platform for future cell-type-specific analysis in other plant developmental contexts. In this work, these sampling techniques have lead to new insight into both meristem . regulation and auxin function in the SAM. Most interestingly, in terms of auxin signalling, it appears that the negative regulators of auxin response, JAAI2 and IAAI8, arc expressed specifically in the PZ and, unexpectedly y, their expression is down-regulated by auxin. Moreover, the gem: ontology analysis of the genes obtained by RNA-seq revealed an enrichment of genes involved in DNA synthesis and response to external stimuli in the PZ. This is consistent with the higher proliferation rate of the PZ cells and might suggest that environmental inputs are perceived in the PZ. which then affects the identity of the entire SAM. These data, together with detailed phenotypic analysis of multiple mutants involved in auxin signalling and meristem function, provide a framework for understanding the complex role of auxin in the regulation of lateral organ formation through the life of a plant.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.610902  DOI: Not available
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