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. Recently, we determined the expression patterns of 22 auxin response factors (ARFs) in the syncytia induced by the beet cyst nematode in Arabidopsis roots. Read more about Elucidating the mode of action of phytohormone signaling in plant × nematode interactions.
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. My team is currently investigating genome-wide epigenetic modifications that are associated with infection by cyst and root-knot nematodes in a number of model and crop plant species. Read more about Epigenetic control of plant-nematode interaction
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. Read more about Functional characterization of cyst and root-knot nematode effector genes
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. Recently, we have structurally characterized a homodimeric complex of a novel protein SHMT related to nematode resistance in soybeans. Read more about Characterizing molecular mechanisms of soybean resistance to pathogens
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. The underlying molecular mechanisms controlling these processes are largely unknown. Read more about Host Plant Responses During Compatible and Incompatible Plant-Nematode Interactions
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.
Research was initiated in the mid 1990s to study how SCN affects the fungus that causes BSR (Phialophora gregata, now sometimes called Cadophora gregata) and how the nematode affects BSR disease symptom development, infection and colonization by the BSR fungus, and soybean yield. Read more about Interactions of SCN with brown stem rot of soybean
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. Read more about Studies of the interactions of SCN with the soybean aphid
Masonbrink, R., Maier, T. R., Seetharam, A. S., Juvale, P. S., Baber, L., Baum, T. J., & Severin, A. J. (2019). SCNBase: a genomics portal for the soybean cyst nematode (Heterodera glycines). Database, 2019.
SCNBase is currently supported by the North Central Soybean Research Program, as part of a larger effort to enhance durability of SCN resistance for long-term, strategic SCN management.