Below is a summary of our current research interests, but work in the Kud lab is by no means limited to these areas. Prospective students and postdocs interested in working in any areas related to molecular and applied nematology including effector biology, nematode adaptation mechanism, host resistance, cover cropping, and biochemical plant-nematode interactions are encouraged to contact Dr. Kud to discuss their research interests and potential funding opportunities.
Our lab focuses on PPNs posing the greatest risk to Arkansas agriculture, including soybean cyst nematode (Heterodera glycines, SCN), southern root-knot nematode (Meloidgyne incognita, RKN), and reniform nematode (Rotylenchulus reniformis, RN). These nematode species are the most problematic on soybean (Glycine max) and upland cotton (Gossypium hirsutum), major cropping systems in the state.
1. Metaeffectors
Many PPNs are endoparasites that establish a long and complex biotrophic relationship with their hosts to ensure reproduction. This is archived through large repertoires of secretory effector proteins which, upon delivery to host cells, facilitate the transformation of root cells into nematode feeding sites and protect the nematodes from plant defenses. Although studies on nematode effector biology have exploded over last decade, researchers often focus on investigating them individually. Given that endoparasitic PPNs bombard host cells with a large repertoire of effectors (hundreds), there is a considerable opportunity for these proteins to interact with and regulate each other during infection. The higher-order effector that functions as both a normal effector targeting a host protein, and a regulator of another effector within the host cell is referred as a “metaeffector”. Although the concept of effector-effector interaction is rather new and poorly understood, its importance cannot be overlooked since it adds another layer of regulatory complexity to the effector network. RHA1B is a potato cyst nematode (Globodera pallida) effector capable of suppressing plant immunity through its E3 ligase enzymatic activity. Although many host proteins are targeted by RHA1B for ubiquitination and most often degradation, the impact of this effector on other G. pallida parasitic proteins in unknown.
2. Root exudates
Root exudates are a rich source of biologically active compounds, which plants use to shape their ecological interactions. Due to metabolic diversity and ever-changing dynamics of root exudate composition, the impact of only certain molecules on nematode biology has been examined in detail. The evidence suggests that selective breeding efforts for increased yield usually lead not only to trade-offs with gene-for-gene resistance but also adversely impact beneficial traits associated with plant biochemical defenses. If parasitic gene activators from root exudates are identified in the future, breeding efforts to obtain crop varieties with low expression of such elicitors may lead to enhanced nematode resistance. Alternatively, the molecular mechanisms regulating their expression may be good targets for nematode control through host delivered RNAi methods. The modulation of the chemical interactions between plant roots and PPNs has the potential to be a novel management strategy for plant parasitic nematodes.
3. Nematodes and viruses
Restrictions on use of chemical nematicides, such as methyl bromide, have put studies on alternative methods of nematode control in the spotlight. Among safer alternatives are biological control agents (BCAs). Many examples show that viruses are viable as BCAs for limiting the impact phytopathogens, such as fungi, bacteria, insects, and even other viruses, have on crops. Viruses are obligate intracellular parasites found in all organisms that sometimes cause diseases in their hosts, and, if found in nematodes, could be explored as a potential tool for their control.