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Research

  • Though SCN-resistant soybean varieties frequently are available to minimize yield loss, producers are faced with limited options for rotation once virulent SCN populations develop in their fields. The widespread lack of genetic diversity in SCN resistance in soybean has significantly increased the prevalence of virulent SCN populations and reduced the effectiveness of current sources of resistance. Thus, we have two major research challenges that, when successfully achieved, will enable us to develop more efficient management practices for this pest in the future.

  • Studies of the interactions of SCN with the soybean aphid

    The soybean aphid, Aphis glycines, was first discovered feeding on soybeans in Iowa and other Midwestern states in 2000. Since then, it has spread throughout the state and region. Currently, soybean aphids are found in every county in Iowa and the insect has become a serious yield-reducing pest of soybeans in the state.

  • Interactions of SCN with brown stem rot of soybean

    Iowa fields are commonly infested with both SCN and brown stem rot (BSR). In the early 1990s, researchers observed that BSR-resistant soybean varieties had much greater than expected levels of BSR disease in fields infested with SCN than in those without SCN.

  • Field evaluation of SCN-resistant soybean varieties

    An effective and affordable way to manage SCN is to grow resistant soybean varieties. SCN-resistant soybean varieties suppress SCN reproduction, reducing the yield loss caused by damage from nematode feeding. SCN resistance preserves the yield of soybean varieties growing in SCN-infested fields.

  • Host Plant Responses During Compatible and Incompatible Plant-Nematode Interactions

    Nematodes induce multifaceted changes in plant cellular metabolism and gene expression during the infection process that ultimately gives rise to specialized feeding cells (syncytia) within host plant roots.

  • Identification and Functional Analysis of Nematode Esophageal Gland Secretions

    With regard to the nematode, we have been focusing on the identification and functional analysis of nematode genes encoding esophageal gland secretions (i.e. nematode parasitism genes) as part of a Molecular Nematology collaboration with the labs of Dr. Eric Davis (NCSU), Dr. Dick Hussey (UGA), Dr. Thomas Baum (ISU), and Dr. Xiaohong Wang (Cornell).

  • The Role of Phytohormones in Plant-Nematode Interactions

    Phytohormones have been known for decades to modulate plant development; however, the molecular mechanisms involved are only beginning to be discovered. Although not well understood, several lines of evidence suggest considerable interplay and crosstalk among various phytohormones for the modulation of plant growth.

  • Characterizing molecular mechanisms of soybean resistance to pathogens

    In collaboration with experimental scientists, our computational methods are often applied to study specific biological systems, characterizing specific diseases in human, animals, and plants. One such application is studying plant-nematode interactions to understand the molecular mechanisms behind the damage caused by these plant parasites and discover new ways of plant resistance.

  • Functional characterization of cyst and root-knot nematode effector genes

    Plant-parasitic nematodes inject an array of effector proteins into host roots to promote the parasitic interaction.  These effectors are expressed specifically in the nematode’s esophageal gland cells. While it now appears that these effectors contribute to disease, the underlying mechanisms remain largely unknown. We are interested in elucidating the molecular mechanism through which these effectors suppress plant defense responses and modulate other cellular processes and molecular functions in order to initiate and maintain functional feeding sites.

  • Epigenetic control of plant-nematode interaction

    Recent discoveries from my lab indicate that epigenetic modifications, biochemical modifications of DNA and associated proteins, play key roles in shaping the compatibility of the interactions between host plants and plant-parasitic nematodes.

  • Elucidating the mode of action of phytohormone signaling in plant × nematode interactions

    In accordance with the central roles of phytohormones in cellular differentiation and organ morphogenesis, a growing body of experimental evidence indicates that plant-parasitic cyst and root-knot nematodes interfere with hormonal biosynthesis pathways and their signal transduction cascades to drive the infected root cells into becoming specialized new feeding cells.