Characterisation of miRNA during drought stress in wheat plants

Alshammari, Mamdouh (2022) Characterisation of miRNA during drought stress in wheat plants. Doctoral thesis, University of East Anglia.

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Climate change is one of the main global themes that impact human food security. Wheat is a staple food for more than two billion of the world's population, whose production will need to increase by 60% in the coming decades, under the backdrop of climate change. Drought has been the most important limiting factor for wheat productivity. Many studies on model plants have demonstrated that miRNAs play a major role in drought stress responses, however, very little is known about their function in wheat. To gain insights into the role of miRNAs in drought stress in wheat we used two wheat varieties (Pavon 76 and Yecora Rojo) with different responses to drought. Small RNA sequence data were obtained from 48 leaf and root samples for both varieties under well-watered and water deficit conditions. Principal Component Analysis clustering showed that miRNA expression in leaf samples was very different from root samples. Under drought stress, Pavon 76 and Yecora Rojo samples were clustered in two distinguished groups, while under well-watered conditions no clear separation was observed.

As a result, a total of 44 different miRNA sequences were found differentially expressed that can be derived from 90 loci. The miRNA sequences were compared to all plant miRNAs deposited in miRbase ( We found that 27 of the differentially expressed miRNAs belong to 21 miRNA families and 8 of these are conserved (miR160, miR166, miR169, miR319, miR396, miR398, miR528 and miR9657) while the other 13 are non-conserved miRNA families. While, the family miR164 have 4 family members and the families miR172, miR390 and miR9772 have 3 members, each. The other 9 miRNA families (miR171, miR530, miR827, miR874, miR1120, miR5067, miR5070, miR9674 and miR9776) have less than three family members, each. In addition to the 27 (21 families) known miRNAs, the 44 differentially expressed miRNAs also included 17 miRNAs that could not be
assigned to any of the known miRNA families.

MiR319, miR528, and miR7714 were selected for further validation. Northern blot analysis showed fairly good signals for the three miRNAs, but the extent of the signal was different for each one, with clear changes in the expression pattern between well-watered and water deficit treatments confirming the results obtained from the sequencing analysis. Target genes of the selected miRNAs were predicted and their cleaved mRNA fragments were successfully amplified using 5’RACE. However, only the miR319 cleavage site was confirmed by sequencing. The current research has important implications for future studies to develop drought-resistant wheat that can cope with the unpredictable stresses associated with climate change and ensure food security for the future.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Nicola Veasy
Date Deposited: 25 Oct 2023 13:53
Last Modified: 25 Oct 2023 13:53


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