الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
SUMMARY
This study was carried out at the Department of Genetics, Faculty of Agriculture, Ain shams University and the Environmental Stress Laboratory (ESL) at Agriculture Genetic Engineering Research Institute (AGERI), Agriculture Research Center (ARC), Giza, Egypt, during the period from 2014 to 2017. It aimed to study and correlate between ten miRNAs and drought tolerance in Egyptian hexaploid wheat cultivar (G168). The ten miRNAs were selected based on previous studies showed alterations of these miRNAs in response to drought stress and their names were according to miRBase database version 21.
Seedling plants were treated with PEG 6000 to induce drought tolerance mechanisms and samples were collected before treatment (control), after treatment by two hours (Treatment 1) and after 12 hours treatment (Treatment 2). The expressions of miRNAs were studied using stem-loop reverse transcription combined with qPCR.
Six RNA-sequencing data for the same cultivar and treatment were analyzed to correlate the expression of miRNA with their targets. Further, in silico analysis was made including, target prediction, functional annotation, gene set enrichment analysis and pathway analysis.
The main findings of this study were as follows:
1. Expression of 10 miRNAs was measured using qPCR after reverse transcription with stem loop primers.
2. Only one miRNA (cre-miR1169) did not show differential expression between control and the two treatments.
3. Eight of miRNA showed up regulation expression after the seedlings treatment with PEG 6000. These miRNAs were osa_miR319a-3p.2-3, miR5048, gma-miR5783, hci-miR156a, bdi-miR159b-3p, ssl-miR398, zma-miR164g-3, ptc-miR482c-5p and osa_miR319a-3p.2-3.
4. Only osa-miR172b was down regulated.
5. Six experiments of RNA-sequencing data were retrieved from database belonging to the same cultiver (G168) and the same treatment.
6. The result indicated that 401 differentially expressed genes were found with P-value less than 0.05.
7. Out of these 401 genes, 104 genes have potentials to be new genes and the other 298 were found in the reference cDNA.
8. Only 87 of them were down regulated after two hours from treatment with (PEG 6000), but after 12 hours only 69 remain down-regulated.
9. The functional annotation of differentially expressed genes showed that 10% of the genes were involved in biological process, 43% in molecular function, and 22% in cellular components, while the remaining genes had unknown annotation.
10. Target genes were predicted based on matching between the mature sequence of each miRNA and the sequences of wheat mRNA.
11. There were 47 target genes regulated by either cleavage or translation inhibition.
12. Six transcription factors were found to be targets of miRNA including bHLH, C2H2, MYB, NAC, SBP and TCP.