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Title: Characterisation of Putative Transcription Factors (NSP1, NSP2 and NIN) Essential for Nodulation in Medicago truncatula
Author: Kim, Jiyoung
ISNI:       0000 0004 2687 1357
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2009
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Legumes produce a unique organ, the nodule through the symbiotic interaction with rhizobial bacteria. This requires perception of the bacterial signal Nod factor (NF) by the host plant. Nod factors are known to induce the expression of many genes and ultimately nodule formation in their plant hosts. However, how NF signalling induces the expression of nodulation genes remains unknown. In this study, I show that a GRAS protein (NSP1) binds directly to the promoters of early nodulation gene (ENOD). While NSP1 shows direct binding to the ENOD11 promoter in vitro, this association in vivo requires another GRAS protein (NSP2). This suggests that a transcriptional complex of NSP2 and NSP1 is directly associated with the promoters of NFinducible genes. I also show that another putative transcription factor, nodule inception( NIN) is a plasma membrane-localisedtr anscriptionalr egulatort hat binds directly to the promoters of nodulation genes. NIN processing is activated by abscisic acid (ABA). NIN is required for ABA-mediated signalling and allows ABA regulation of nodulation. NF induces NIN instability in epidermal cells. This NF-induced NIN instability is considered to be a key factor in the regulated process of nodulation. This work suggests that a transcriptional complex for nodulation signalling is highly coordinated in diverse signalling processes to ensure proper nodule formation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available