Dissection of molecular interactions between Magnaporthe oryzae effector AVR-PikD and rice NLR Pikp-1/Pikp-2 in planta
H. SAITOH (1), A. Maqbool (2), M. Franceschetti (2), A. Uemura (1), H. Kanzaki (1), S. Kamoun (3), M. Banfield (2), R. Terauchi (1) (1) Iwate Biotechnology Research Center, Japan; (2) John Innes Centre, United Kingdom; (3) The Sainsbury Laboratory, United Kingdom

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most economically devastating diseases of food crops worldwide. Approaches to controlling blast disease have mainly been via the deployment of NLRs. AVR-PikD, an effector from M. oryzae, is directory recognized in rice by the intracellular NLR pair Pikp-1/Pikp-2. Recognition of AVR-PikD by Pikp is mediated by AVR-PikD binding to a heavy metal associated domain of Pikp-1 (Pikp-HMA). Biochemical and structural studies have revealed the molecular details of AVR-PikD/Pikp-HMA interaction. To further investigate the link between recognition of AVR-PikD by Pikp-1/Pikp-2 and immunity-related signaling, we established a transient assay in Nicotiana benthamiana using Agrobacterium tumefaciens to deliver these genes into plant cells. We found that the Pikp HR-like cell death requires co-delivery of AVR-PikD, Pikp-1 and Pikp-2. Structure based mutations at the AVR-PikD/Pikp-HMA interface leads to loss of HR-like cell death. Recently, we have been using co-immunoprecipitation to analyse the interactions between these proteins in planta. We show that (1) Pikp-1 can form a homo-dimer, (2) Pikp-2 can form a homo-dimer, (3) Pikp-1 and Pikp-2 can form a heterodimer, (4) AVR-PikD binds to Pikp-1 but not to Pikp-2, (5) Pikp-1 binds to both Pikp-2 and AVR-PikD together. Further analysis of the AVR-PikD, Pikp-1 and Pikp-2 interactions in planta is in progress with the aim of dissecting this immune recognition event.

Abstract Number: P17-600
Session Type: Poster