The Department of Nematology's weekly NEMA 250 seminar series is presented this week by:

Fangming Xiao, Ph.D. Professor, Department of Plant Sciences, University of Idaho

Seminar Title: “Towards parasitism: how the potato cyst nematode effector RHA1B manipulates the host plant"

Seminar Summary: Animals and plants use pattern recognition receptors (PRRs) to perceive conserved molecular patterns derived from pathogens thereby activating the immune responses. The most abundant nematode ascoraside Ascr18 is a nematode-associated molecular pattern (NAMP) that induces immune signaling and enhances resistance to pathogens in various plant species. The Arabidopsis NEMATODE-INDUCED LRR-RLK1 (NILR1) protein is the immune receptor of the nematode NAMP Ascr18, mediating Ascr18-triggered immune signaling and resistance to pathogens. Significantly, the potato NILR1 (termed StNILR1) also recognizes Ascr18 and is required for resistance to potato cyst nematode Globodera pallida. On the other hand, successful plant-parasitic nematodes use stylet to deliver effectors into plant cells to suppress host defenses and/or manipulate host metabolism and development. Our present study indicates that the G. pallida effector RHA1B, which is a functional ubiquitin ligase, directly interacts with StNILR1 and a deadenylase complex involved in RNA metabolism promoting their degradation via the 26S proteasome. Thus, these results suggest that G. pallida utilizes the effector RHA1B to interfere with the NAMP-triggered immunity and a RNA metabolism machinery, thereby promoting parasitism.