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Home > Effects of Potato Polyphenol Oxidase Gene Silencing in Transgenic Tobacco

Effects of Potato Polyphenol Oxidase Gene Silencing in Transgenic Tobacco

Thesis Info

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Author

Aziz, Ejaz

Supervisor

Tariq Mahmood

Program

PhD

Institute

Quaid-I-Azam University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2017

Thesis Completion Status

Completed

Subject

Botany

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/7985/1/Ejaz%20Aziz%20Ph.D%20Thesis.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726026722

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Polyphenol oxidases (PPOs) are nuclear encoded copper metalloenzymes that catalyze the oxidation of ortho-diphenols to ortho-quinones. PPO genes play an important role in plant defense mechanisms against biotic and abiotic stresses as well as responsible for undesirable browning in some fruits and vegetables. In the current study, ninety five PPO gene coding sequences from thirty six different plant species were analyzed in silico for multiple sequence alignment and phylogenetic relationships to gain insight into the structure-function relationships within the plant PPO family with special emphasis on potato. The obtained results indicated highly conserved copper binding domain in all the studied sequences. Phylogenetic clustering of monocot and dicot PPO proteins into separate groups reflects the lineage specific gene family expansion and duplication events through evolution. Interestingly, grand average of hydropathicity values proposed that all potato PPO proteins are hydrophilic in nature. To evaluate the stress induced expression of PPO gene, in vitro grown tobacco plants were subjected to wounding, abscisic acid (ABA) and methyl jasmonate (MeJ) stresses. Transcript levels measured by qRT-PCR for endogenous tobacco PPO gene showed an up-regulation of 14 folds by wounding and 6 folds by MeJ application, while no significant induction was observed with ABA treatment. An up-regulation of endogenous PPO gene in response to wounding and MeJ suggested a possible role of PPO in biotic stresses. Keeping in view the role of tobacco endogenous PPO induction by wounding and MeJ as well as already studied reports of PPO in other plants, Agrobacterium tumefaciens mediated genetic transformation of in vitro grown tobacco plants was carried out. The expression construct containing a copper binding domain segment of PPO gene ligated in anti-sense orientation downstream to a wound inducible OsRGLP2 promoter in p1391Z backbone vector was used for this transformation event. Expression analysis of transgenic tobacco plants with OsRGLP2 driven anti-sense segment of PPO gene was carried out with qRT-PCR in response to various stresses e.g. wounding, MeJ, ABA and whitefly (Trialeurodes vaporariorum) infestation. Expression analysis of PPO gene in transgenic tobacco showed a significant higher suppression (3.5 folds) of PPO in response to wounding. Similarly, MeJ application down-regulated the PPO expression up to 4.7 folds, while no significant expression of PPO was observed in vii case of ABA treatment. Moreover, considerable level of PPO reduction (6 folds) was observed with whitefly feeding assay in transgenic tobacco. These results indicated that expression of potato PPO in an anti-sense orientation has down-regulated the PPO activity. This down-regulation of PPO by wounding, MeJ and whitefly infestation clearly links the role of PPO in biotic as well as abiotic stresses. PPO gene suppression in transgenic plants by using anti-sense potato PPO gene construct suggested that this tool can be used to inhibit the enzymatic browning in fruits and vegetables e.g. potato
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سیالکوٹ کی سر زمین میں سب سے پہلی بزم ’’دائرۃ الا دب‘‘ تھی۔یہ تنظیم ۱۸۹۰ء میں معرض وجود میں آئی۔(۹۹)

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Women and Feminism: A Discourse Analysis of Contemporary Theories and Islamic Teachings

Modern social activists through media present Islam’s view about women as an oppressed figure linked to her sexuality through so-called liberalism; her oppression is particularly symbolized by obsessive concern with sex, women’s bodies, the veil, and female isolation. While on factual grounds such mind set and groups have oppressed women by judging their worth as persons based on physical attractiveness. Such modern trends and feministic approaches have turned the image of woman as tool of entertainment or attraction. Those who are convinced by such modern values regard woman‘s status in Islam as inferior on the basis of several issues including; guardianship in marriage, polygamy, divorce right. Unfortunately this horrible disease has crept into Muslim societies in the name of cultural interrelation which is in total disregard for our purity and distinguishing values. The magnitude of women rights in Islam with comparison to feminism has been covered in this brief paper. The first part of the paper gives image of women in western society and bases for initiatives taken for feminism movement in west. Second part of the paper gives a comparison between Islamic approach of women rights and feminism. Third part of the paper describes the view of women liberation and modernity in western society. In fourth part of the paper discussion about women oppression has been presented. In fifth part Islamic view of women rights has been given through Quranic verses and references which is followed by findings and conclusion of the whole discussion

Eco-Physiological Responses of Velvet Bean Mucuna Prurien to Inoculation With Rhizobacteria Containing Acc-Deaminase under Drought Stress

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