Theses and Dissertations

Issuing Body

Mississippi State University


Lawrence, Gary

Committee Member

Klink, Vincent

Committee Member

Long, David

Committee Member

Lawrence, Katheryn

Committee Member

Lu, Shien

Date of Degree


Document Type

Dissertation - Open Access


Plant Pathology

Degree Name

Doctor of Philosophy


College of Agriculture and Life Sciences


Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology


Soybean cyst nematode (H. glycines), reniform nematode (R. reniformis), and Root-Knot nematode (M. incognita) are three damaging plant-parasitic nematodes on soybean. Syntaxin proteins are involved in the process of membrane fusion. T wo G. max syntaxin genes (Gm-SYP22-1, and Gm-SYP22-2) that were similar in amino acid composition have been found to contribute to the ability of Glycine max to defend itself from infection by the plant parasitic nematode Heterodera glycines. Syntaxin genes SYP22-1 and SYP22-2 were identified to be expressed specifically in syncytia undergoing a resistant reaction to H. glycines parasitism. The Gm-SYP22-1 and Gm-SYP22-2 genes were isolated by molecular means and genetically engineered in G. max [Williams 82/PI 518671], a genotype typically susceptible to H. glycines parasitism. Genetically engineered control plants in G. max [Williams 82/PI 518671] that lack the overexpression of Gm-SYP22-1 or Gm-SYP22-2 genes were produced to serve as a comparison. The transgenic Gm-SYP22-1 or Gm-SYP22-2 overexpression lines with their pRAP15 control have then been infected with H. glycines. In another study, tests include three separate tests in 2015 and one test in 2016 that evaluated different biological products, application rates and product combinations as seed treatments on soybeans. Results collected from soybean plants that were infested with either H. glycines, M. incognita or R. reniformis indicated that many of these biological products significantly reduced the nematode reproduction compared to control. The number of cyst, juveniles, and eggs recovered were significantly reduced compared with the non-treated control. Other findings identified Burkholderia renojensis variant 2 (BioST Nematicide) as being a more consistent nematicide candidate when referencing data from all nematodes and rate ranges. Combinations of B. renojensis variant 2 with selected SAR (systemic acquired resistant) products numerically improved the efficacy and consistency of the biological nematicide. Another study focused about investigated of biological seed treatments on H. glycines, and F. virguliforme indicated that many of these biological products significantly reduced the nematode reproduction over the fungicide only check. Foliar disease severity happened more in the treatments that infested with H. glycines + F. virguliforme combination than F. virguliforme alone.



H.glycines||R. reniformis||M. incognita||Burkholderia renojensis