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Home > Detection & Molecular Characterization of Candidatus Spp. Causing Hlb in Indigenous Citrus Cultivars and its Control by Genetic Manipulation of Citrus Genome

Detection & Molecular Characterization of Candidatus Spp. Causing Hlb in Indigenous Citrus Cultivars and its Control by Genetic Manipulation of Citrus Genome

Thesis Info

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Author

Bibi, Ambreen

Program

PhD

Institute

Lahore College for Women University

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2018

Thesis Completion Status

Completed

Subject

Biotechnology

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/12697/1/Ambreen%20Bibi_Biotech_2018_LCWU_PRR.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725830925

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The citrus fruit ranks at the top in production and trade among all fruits produced the world over. It is highly prized and remunerative fruit, cultivated almost all over the world. Citrus comprises about 40 percent of all fruits that grow in Pakistan. It is cultivated over an area of 206,569 hectares with an average annual production of about 2.36 million tons per annum. Pakistan citrus industry is facing different pre-harvest and post-harvest problems including bacterial, viral diseases, pest attack, poor management and under developed citrus industry. All the mentioned problems lead to failure and declining citrus industry. The current decline in citrus production in the country is attributed to a great extent to Huanglongbing (HLB) or Citrus greening disease. HLB is transmitted by grafting and psyllids Diaphorina citri. HLB disease is hard to control due to having an aggregated nature of disease symptoms, prolong incubation period and may remain symptomless in certain host plants. The movement of HLB bacterium is unevenly distributed in phloem sieve tubes, leaf midrib, and vascular tissues in bark, floral parts and in roots. These symptomless infected plants prove more dangerous as they are continuous source of infection spread through the vector. Another difficulty related to this disease is its symptoms as these are similar with nutrient deficiencies or other viral diseases such as CTV in citrus plants. This study was consummated to characterize the causative agent of citrus HLB disease in different orchards of Pakistan. The distribution of HLB disease across agroecological zones and citrus varieties of two orchards viz. “Citrus Research Institute, Sargodha (CRI)” and “Bursha Citrus Research & Development Center, Sillanwali, Pakistan” were observed. Symptomatic and asymptomatic leaves of citrus trees were randomly sampled, scored and stored at 4°C. Bacterial DNA isolated from the leaf midribs was subjected to PCR to amplify specific ribosomal regions on Candidatus Liberibacter genome (16S rDNA, 16S/23S rRNA) and OMP gene fragments. These amplicons were sequenced and systematically analyzed for homology. The data from CRI orchard’s samples revealed HLB infection in symptomatic as well as non-symptomatic trees of all varieties. All the six groups of citrus were infected with HLB infectious agent. Kamquat and Sweet Oranges were severely infected with HLB associated bacterium having 86% and 66% prevalence. Grapefruit revealed Candidatus Liberibacter asiaticus (Las) incidence in 40% samples. Lemon and limes revealed 47% and Mandarin showed 31% of HLB infection rate. Of the total 466 citrus samples of 6 groups, 249 samples were found positive for HLB pathogenic bacterium. Total 53% samples of CRI were infected with Candidatus Liberibacter asiaticus. The varietal samples collected from Sillanwali orchard revealed 11% HLB infection, of which only 4 varieties had harboured Candidatus Liberibacter asiaticus causing HLB disease whereas 34 varieties were found HLB disease free. The current study was conducted to develop Agrobacterium-mediated transformation protocol of epicotyls explants of rough lemon (rootstock) using pAFS-SUC2-D4E1 recombinant vector. Transformation experiments were performed with Agrobacterium tumefaciens strains LBA4404 and GV3101 harboring a binary vector pCAMBIA 1301. Kanamycin, Acetosyringone concentrations, optical density of Agrobacterium culture, preculturing and co-culturing period were investigated during transformation. Transgenic shoots were selected on 100 (mg/L) kanamycin along with (250 mg/L) each of cefotaxime and vancomycin for effective inhibition of Agrobacterium growth. The Murashige and Skoog (MS) medium containing 200 μM acetoseryngone proved to be the best inoculation and co-cultivation medium for transformation. MS medium supplemented with 3 (mg/L) of 6-benzylaminopurine (BAP) showed maximum regeneration efficiency of the transformed explants. By combining the best combinations of the transformation factors, achieved highest transformation efficiency (24.19 %). The integration of SUC2-D4E1 expression cassette in transgenic plantlets was confirmed by conventional PCR analysis and mRNA of the gene in the host plant. A rapid and efficient protocol was established to produce HLB resistance against the infectious agent in transgenic plants. Although the transformation efficiency was not very high (24.19 %) which can be improved with further developments, however, this would provide an effective preliminary procedure for Agrobacterium mediated transformation in citrus. The protocol opens up new avenue for genetic improvement of the current as well as other citrus cultivars with valuable genes to attain sustainable and higher production.
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مولانا قاری محمد اسحاق نقشبندی مجددی

موت العالِم موت العَالم
متوسلین سلسلۂ مجددیہ نقشبندیہ کویہ معلوم کرکے بڑاافسوس ہوگاکہ حضرت مولانا قاری محمداسحاق صاحب نقشبندی مجددی نے جوحضرت مولانا مفتی عزیز الرحمن صاحب عثمانی دیوبندیؒ کے جانشین اورخلیفۂ مجاز اوراس سلسلہ کے اکابر مشائخ میں سے تھے۔۵؍جولائی ۴۵ء کونماز ظہر کے وقت میرٹھ لال کرتی میں رحلت فرمائی۔ اناﷲ واناالیہ راجعون۔ حضرت مرحوم کے متوسلین سے توقع ہے کہ وہ حضرت مرحوم کی روح پر فتوح کو ایصالِ ثواب کرکے داخل حسنات ہوں گے۔ [ادارہ، جولائی ۱۹۴۵ء]
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طبی شعبہ میں ضرورت و حاجت سے متعلقہ فقہی قواعد کی معاصر تطبیقی صورتیں

Emergence of biomedical research and innovation with an unprecedented speed has created number of opportunities and challenges for policy makers. On the one hand, it is now possible to introduce tailor-made personal medication regime for an ailing patient to offer state of the art treatments. On the other hand, several ethical and legal issues have been raised due to the complex nature of emerging technologies.  Policy makers all over the world are constantly addressing these challenges by continuously upgrading their respective professional and regulatory frameworks. This article is an attempt to highlight Shariah maxims which have contemporary application in medical field. Lately, there has been a lot of interest in the debate of Shariah maxims and many scholars have used maxims-based analytical frameworks to show the dynamic application of Islamic law. This article builds upon those works by focusing on issues related to the medical field.

The Role of U. S. Media in Shaping Foreign Policy Towards Pakistan a Case Study of New York Times and Washington Post 2001-2008

The U.S.-led Global War on Terror (GWOT) has had profound implications for Pakistan as its front-line state. The alliance between the U.S. and Pakistan brought changes to socio-economic and diplomatic landscape of Pakistan. Though the U.S.-Pakistan relations underwent a revival phase in post 9/11 scenario, this coalition did not help to dispel negative perception of Pakistan in the U.S. media. Pakistan has been working closely with U.S. on military and intelligence front, but failed to raise its case at diplomatic level and correct its position in the media. With rapid technological development, the news media is considered critical in promoting national security goals. The sophisticated U.S. media having covered foreign policy issues since Vietnam War is considered critical, particularly in wars and international conflicts to promote sense of U.S. national identity. After 9/11, the U.S. through its media portrayed the same sense of unity among allies in its campaign against terrorism and positioned the country as a moral leader among nations. This study presents the media framing of Pakistan; how it is portrayed in the U.S. mainstream media and examine their stance towards U.S-Pakistan relationship after 9/11 while testing the foreign policy decision-making theory. This is done by examining the two U.S. mainstream newspapers: The New York Times and The Washington Post’s editorials from 2001-2008. The methodology has incorporated traditional quantitative method of content analysis and qualitative investigation to examine how the U.S.-Pakistan relations are projected through the dominant U.S. media frames reflecting the U.S. foreign policy towards Pakistan after 9/11. The media framing analysis has verified the media’s role within the domestic input category of foreign policy decision making theory which shows that in foreign policy making process, media contributes in shaping a foreign country’s image, thus influencing policy towards that country, while supporting its national security interests. The study also finds an independent role of the U.S. media which does not follow the U.S policy positions except major national interest, contrary to a perceived notion that media is a propaganda tool of U.S. Government. The independent role of the U.S. media is found in criticizing the U.S. Government’s support for General Musharraf’s military rule over civilian government in Pakistan; the U.S. policy in overlooking the restoration of democracy in Pakistan and positive media framing for the U.S.-India strategic partnership over Pakistan during the first eight years of alliance. The study also proposes policy level recommendations for Pakistan to enhance media’s role in national security policy and improved U.S.-Pakistan’s image through joint media ventures between the U.S. and Pakistani media outlets.