- Title
- Profiling the abiotic stress responsive MicroRNA landscape in Arabidopsis thaliana
- Creator
- Pegler, Joseph Leigh
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- There is overwhelming scientific consensus that anthropogenically driven global warming and the burgeoning global population are having, and will increasingly have, detrimental impacts on natural ecosystems and human health. One such pressing issue is the ability to provide food security for a growing human population with a largely insufficient global crop yield to land capability ratio, together with the increasing prevalence of unfavourable plant growth conditions associated with global warming. It has been evident in recent decades that the unsustainable practise of clearing ecosystems rich in biodiversity for the cultivation of additional food crops must be replaced with an alternate approach, such as a molecular modification approach that targets crop yield improvement: with crop yield one of the traits of a plant that is extremely susceptible to climate change. MicroRNAs, a class of small (21 to 24 nucleotide (nt)) regulatory RNA, are well documented to act as ‘master regulators’ of plant development as well as demonstrated to play an additional role in plant adaption to abiotic stress. Therefore, the molecular modification of such abiotic responsive miRNAs provides an attractive alternate avenue for the generation of plant lines that display tolerance to abiotic stress. As a first step to achieving this goal, this study utilised a high throughput small RNA sequencing (sRNA-seq) approach to profile the miRNA landscape of wild-type Arabidopsis thaliana (Arabidopsis) plants exposed to heat, drought and salt stress. sRNA-seq identified large miRNA cohorts responsive to each applied stress, with 121, 123 and 118 miRNAs determined to have a greater than 2.0-fold change in abundance post heat, drought and salt stress treatment of Arabidopsis plants, respectively. From this large number of potential targets for future molecular modification, the miRNAs, miR396 and miR399, and their respective regulatory modules, were selected for further characterisation. A transgenesis approach was used to generate miRNA knockdown and overexpression plant lines for the miR396 and miR399 sRNA. This approach revealed that the molecular manipulation of miR396 and miR399 sRNA abundance impacted on numerous aspects of the growth and development of Arabidopsis plants; either under standard growth conditions, or when exposed to a 7 day stress regime of either phosphate deficiency or salt stress. The information presented in this research thesis provides a foundation for the selection of crucial abiotic stress responsive miRNAs whose molecular manipulation provides the modified plant lines with a degree of tolerance to the imposed stress. This research thesis additionally provides further extensive molecular evidence of the essential regulatory role that DRB1, DRB2 and DRB4 play in miRNA production, both in non-stressed Arabidopsis plants, and in Arabidopsis plants post their exposure to heat, mannitol and salt stress, or when Arabidopsis is cultivated in the absence of phosphate.
- Subject
- MicroRNAs; abiotic stress responsive; Arabidopsis; molecular modification; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1421876
- Identifier
- uon:37776
- Rights
- Copyright 2020 Joseph Leigh Pegler
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 17 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 394 KB | Adobe Acrobat PDF | View Details Download |