الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
SUMMARY
This study was carried out in the department of Genetics (Ain Shams Center of Genetic Engineering lab. ), Faculty of Agriculture, Ain Shams University, Egypt.
In Egypt, the geographical distribution of endemic plants (Brassicaceae) is still undescribed. Besides, under the current climate conditions, and its future variation in relation to the climate change issue, it was substantial to take a part and start the first step regarding validating the Egyptian endemic plants presented in Brassicaceae. This study confers preliminary assessment data that will be useful during DNA barcoding investigations for endemic plants. With the current concatenated tree, we found that DNA barcoding is essential for accurate plant species identification, where relying only on morphology characters might be misleading. However, further protocol development to increase number of plants, various gene markers, including different regions, and local authenticated databases would enrich plant barcoding efficiency.
This study aimed to characterize some of the Egyptian endemic genetic resources on the molecular level to sustain the Egyptian plant genetic wealth. Further, to address whether morphological identification is sufficient for characterization or confirmed with the molecular characterization. Therefore, 16 Brassicaceae endemic species were collected from two different geographical locations and barcoding them using two chloroplast markers. Later, we generated a robust concatenated phylogenetic tree was generated concerning the Brassicaceae family not only for our collected taxa but also for all reference nucleotide sequences available on the database based on the two selected markers (rbcL-a and matK).
For this purpose, DNA extraction and barcoding of 16 different species which collected from two different localities in Egypt, and then Phylogenetic analyses have been done.
The most important obtained results are as the following:
The variation in a partial segment of the chloroplast rbcL gene can be used to identify Brassicaceae species in line with previous DNA studies of the family.
1- Among all pairwise combinations in 16 species, the mean matK divergence was 0.18%, with a range of 0% to 1.159%, and the most nucleotide divergence ranged from 0.012% to 0.926%.
2- the rbcL data show a narrow range of divergence ranging from 0% between the Sinapis alba (Brassiceae tribe) and both Brassiceae tribe’s members Brassica nigra and Brassica tournefortii to 0.025% between the Brassiceae tribe’s member (Raphanus sativus) and the lepidieae tribe member (Lepidium didymus).
3- The matK data showed a wide range of divergence ranging from 0.012% between the Eruca vesicaria subsp. Sativa (Brassiceae tribe) and another Brassiceae tribe’s member (Diplotaxis harra) to 1.159% between both Alysseae tribe’s members Lobularia arabica and Farsetia aegyptia.
4- The concatenated tree based on the two markers showed that 12 out of 16 species were completely matching with the morphological identification.
5- High bootstrap supports were obtained for the two markers of 12 species matched the morphological identification. However, there remains a remarkable uncertainty level for four species, such as Lobularia, Erucaria, and Cakile.
In conclusion, the primary target beyond this study was to authenticate the Egyptian endemic plant wealth to go further with the downstream studies related to the active components used in the pharmacological and medical sectors. This study constitutes the first report exploring the molecular phylogeny between the Egyptian Brassicaceae tribes based on DNA sequencing, not only on the morphological identification. To obtain a robust phylogenetic tree and get a highly accurate relationship between the target species, the standard barcode loci (rbcL-a and matK) have been relied on not only for the collected species but along with 117 Brassicaceae genera in the database. This study provides robust assessment data by making use of DNA barcoding applications to validate Egyptian endemic plants. However, future work should be done using more than two genetic markers supplemented with biochemical studies that should together enrich the plant barcoding data.