Characterization of horizontally transferred vitamin B biosynthesis genes in the soybean cyst nematode, Heterodera glycines

Ahmed, Ibtesam

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https://hdl.handle.net/2142/49743 Copy

Description

Title

Characterization of horizontally transferred vitamin B biosynthesis genes in the soybean cyst nematode, Heterodera glycines

Author(s)

Ahmed, Ibtesam

Issue Date

2014-05-30T17:07:30Z

Director of Research (if dissertation) or Advisor (if thesis)

Lambert, Kris N.

Department of Study

Crop Sciences

Discipline

Crop Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Soybean Cyst Nematode
• Vitamin B biosynthesis genes
• Complementation
• Cloning
• Horizontal gene transfer
• Phytoparasite

Abstract

Heterodera glycines (H. glycines), commonly known as the soybean cyst nematode (SCN), is an obligate plant parasite and a major pest of soybean. It is highly adapted to manipulate and parasitize host plants. It possesses parasitism/effector genes that enable it to developmentally alter host cells and establish feeding sites inside the host root, and also suppress or counteract host defenses. Currently, there is a lot of interest in identifying and characterizing genes that enable this nematode to parasitize its host in order to find molecular targets for controlling this pest. Seven H. glycines genes, namely panC, bioB, tenA, thi4, thiD, thiE and thiM, have been discovered recently. All these genes are involved in vitamin B biosynthetic pathways forming one complete and two partial pathways. They are potentially important molecular targets because there is evidence to show that these genes have been acquired through horizontal gene transfer from prokaryotes, and have been implicated to play roles in plant parasitic nematode-host interactions. The main goal of this project was to perform complementation experiments in order to determine the function of each of the seven SCN vitamin biosynthesis/salvage pathway genes. To achieve this goal, the cDNA of each of the genes was PCR-amplified using gene-specific primers. Each cDNA insert was cloned into a cloning vector, and transformed into chemically competent Escherichia coli (E. coli) cells. The recombinant plasmid DNA was used to transform mutant E. coli cells deficient in that particular gene. The growth of these transformed mutants was analyzed, in order to understand whether there was complementation. The thiD complementation experiment showed the most clear-cut results. A mutant strain of E. coli deficient in thiD and transformed with thiD-containing vector grew much better in M9 minimal media than the same strain of cells transformed with vector alone. Results from this study also indicated that H. glycines panC, tenA, bioB, thiE partially complemented their corresponding mutant E. coli strains.

Graduation Semester

2014-05

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http://hdl.handle.net/2142/49743

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Copyright 2014 Ibtesam Ahmed

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