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Molecular Genetic Investigation into the Processes Underlying Transitions in Plant Gene Expression

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dc.contributor.advisor Colasanti, Joseph Minow, Mark Allan Alexander 2020-12-11T22:02:47Z 2020-12 2020-11-12 2018
dc.description.abstract This thesis investigates several unanswered questions about how plant transcription factors and small RNA (sRNA) mediate transitions in gene expression. Specifically, this thesis addresses three goals: i) to better understand the maize autonomous flowering pathway and to what extent it overlaps with the ancestral photoperiod flowering pathway, ii) to providing insights into how sRNA transcriptomes change during the creation of maize recombinant inbred lines (RILs) and near isogenic lines (NILs), and iii) to determine if Arabidopsis phloem derived sRNA signals can influence gene expression in the shoot apical meristem (SAM). The first research goal addresses the floral transition, a critical change in SAM gene expression, that initiates reproductive growth. In maize, the transition to reproductive growth is driven by an autonomous pathway controlled by the transcription factor INDETERMINATE1 (ID1). Our RNA-sequencing revealed that ID1 influences the floral transition through a pathway distinct from that used by ancestral maize, teosinte. In pursuit of the second goal, next generation sequencing was used to examine the sRNA transcriptome of maize RILs and NILs. Genome wide, most sRNA expression were found to be co-inherited with the parental DNA. However, RIL non-parental sRNA expression patterns were also observed. These non-parental sRNA expression patterns often resembled the expression state found at the same locus in the other parent. In the NIL, many sRNA expression differences were observed over the introgressed DNA and the homologous region from the recurrent parent. However, the introgressed region had low 24nt sRNA expression, perhaps related to poor genome wide homology and past breeding history. The third goal used two synthetic systems to test phloem-to-SAM sRNA trafficking. Both systems provide evidence of phloem-to-SAM sRNA movement. Since the SAM gives rise to plant gametes, phloem-to-SAM sRNA transport provides a route for somatic sRNA to initiate heritable epigenetic transitions. Understanding the mechanisms behind these various transitions in plant gene expression will ultimately allow for the precise manipulation of traits that improve plant productivity to meet the challenges of climate change in the coming century. en_US
dc.description.sponsorship NSERC Italian Ministry of Education, University and Research (MIUR), the National Research Council of Italy (CNR) forEPIGEN, the Epigenomics Flagship Project en_US
dc.language.iso en en_US
dc.publisher Society for Experimental Biology en_US
dc.rights Attribution-NonCommercial-NoDerivatives 4.0 International *
dc.rights.uri *
dc.subject Maize, Arabidopsis, Flowering, small RNA en_US
dc.title Molecular Genetic Investigation into the Processes Underlying Transitions in Plant Gene Expression en_US
dc.type Thesis en_US Molecular and Cellular Biology en_US Doctor of Philosophy en_US Department of Molecular and Cellular Biology en_US
dc.description.embargo 2021-11-20
dc.rights.license All items in the Atrium are protected by copyright with all rights reserved unless otherwise indicated.
dcterms.relation Minow, M.A.A., Ávila, L.M., Turner, K., Ponzoni, E., Mascheretti, I., Dussault, F.M., Lukens, L., Rossi, V., and Colasanti, J. 2018. Distinct gene networks modulate floral induction of autonomous maize and photoperiod-dependent teosinte. J. Exp. Bot. 69(12). doi:10.1093/jxb/ery110. en_US

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