Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Biology

Supervisor

Abdelali Hannoufa, Denis Maxwell

Abstract

Plants growing under iron deficiency suffer from multiple physiological defects. Although the effects of microRNA156 (miR156) on multiple aspects of plant development have been investigated, a possible role of miR156 in plant iron homeostasis has not been shown. By employing next-generation RNA-sequencing, the current research demonstrated that multiple iron homeostasis-related genes, including ones coding for Ferritins, group Ib bHLH transcription factors, and key enzymes involved in iron uptake, were differentially expressed in Arabidopsis thaliana plants overexpressing miR156. Overexpression of miR156 also enhanced Arabidopsis growth under iron-deficiency. In addition, expression analysis revealed that miR156 is a positive regulator of FIT and PYE genes partially through targeting SPL9 and SPL15. By using Chromatin Immuno-Precipitation qPCR assay, SPL9 and SPL15 were found to have strong binding capability to the promoters of PYE and FIT. Taken together, our data suggests that miR156 is a positive regulator of iron homeostasis through targeting SPL9 and SPL15 in Arabidopsis.


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