The Arabidopsis leucine-rich repeat receptor-like kinase MIK2 is a crucial component of early immune responses to a fungal-derived elicitor

Abstract

Fusarium spp. cause severe economic damage in many crops, exemplified by Panama disease of banana or Fusarium head blight of wheat. Plants sense immunogenic patterns (termed elicitors) at the cell surface to initiate pattern-triggered immunity (PTI). Knowledge of fungal elicitors and corresponding plant immune-signaling is incomplete but could yield valuable sources of resistance. We characterized Arabidopsis thaliana PTI responses to a peptide elicitor fraction present in several Fusarium spp. and employed a forward-genetic screen using plants containing a cytosolic calcium reporter to isolate fusarium elicitor reduced elicitation (fere) mutants. We mapped the causal mutation in fere1 to the leucine-rich repeat receptor-like kinase MDIS1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) and confirmed a crucial role of MIK2 in fungal elicitor perception. MIK2-dependent elicitor responses depend on known signaling components and transfer of AtMIK2 is sufficient to confer elicitor sensitivity to Nicotiana benthamiana. Arabidopsis senses Fusarium elicitors by a novel receptor complex at the cell surface that feeds into common PTI pathways. These data increase mechanistic understanding of PTI to Fusarium and place MIK2 at a central position in Arabidopsis elicitor responses.

Keywords: Arabidopsis thaliana; Fusarium; MDIS1-INTERACTING RECEPTOR LIKE KINASE 2; fungal elicitor; leucine-rich repeat receptor-like kinase; pattern-recognition receptor; pattern-triggered immunity; plant immunity.