The role of short RNAs in Canna indica leaf colour formation

Hesseki, Ohood (2023) The role of short RNAs in Canna indica leaf colour formation. Doctoral thesis, University of East Anglia.

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MicroRNAs (miRNA) are non-coding single stranded RNAs that plays crucial role in regulating gene expression. The objective of this project is to study the colour formation on the leaves of the Canna indica (C. indica) plant using two different approaches. The first the hypothesis I wanted to test was that the red and green sectors of C. indica cv Cleopatra are caused by the absence or presence of transposons. Around 500 differentially expressed genes between red and green sectors of C. indica cv Cleopatra have been identified and several of these were Myeloblastosis (MYBs) and Basic Helix-Loop-Helix (bHLHs) transcription factors. Five MYBs genes and CHS were analysed by PCR but none of them contained transposons, therefore a different approach was taken to find transposons in genes that may interfere with the anthocyanin pathway. Genomic DNA was extracted and the whole genome was sequenced by Pacific Bioscience (PacBio) as there was no available genome sequence for C. indica cv Cleopatra. The bioinformatic analysis identified a potential transposon in an intronic region of a MYB gene that was differentially expressed between green and red sectors. The validation of this transposon was not completed due to a lack of time but is being further investigated by the research group. The second objective was, to identify small RNAs differentially expressed in yellow striped C. indica cv Pretoria and pink striped of C. indica cv Durban compared to plain green and red leaves, respectively. The hypothesis was the sRNAs target enzymes involved in the anthocyanin biosynthetic pathway and silencing these genes resulting in the pinks strip. I also hypothesised that in the green leaves, sRNAs target enzymes involved in the chlorophyl biosynthetic pathway and silencing these genes lead to yellow strips. We found four miRNAs, miR166, miR529, miR530 and miR6300 that were differentially expressed in the different coloured leaves. I identified targets for some of these miRNAs but due to the lack of complete transcriptome sequence we were not able to predict targets for all four miRNAs.

Since the submission of my thesis, the research group took advantage the recently generated Canna genome sequence and found some potential targets for all differentially expressed miRNAs. Validation these targets will shed light on the effect of miRNAs in colour formation in Canna leaves.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Chris White
Date Deposited: 12 Dec 2023 15:39
Last Modified: 30 Jun 2024 01:38


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