An LRR/Malectin Receptor-Like Kinase Mediates Resistance to Non-adapted and Adapted Powdery Mildew Fungi in Barley and Wheat

Abstract

Pattern recognition receptors (PRRs) belonging to the multigene family of receptor-like kinases (RLKs) are the sensing devices of plants for microbe- or pathogen-associated molecular patterns released from microbial organisms. Here we describe Rnr8 (for Required for non-host resistance 8) encoding HvLEMK1, a LRR-malectin domain-containing transmembrane RLK that mediates non-host resistance of barley to the non-adapted wheat powdery mildew fungus Blumeria graminis f.sp. tritici. Transgenic barley lines with silenced HvLEMK1 allow entry and colony growth of the non-adapted pathogen, although sporulation was reduced and final colony size did not reach that of the adapted barley powdery mildew fungus B. graminis f.sp. hordei. Transient expression of the barley or wheat LEMK1 genes enhanced resistance in wheat to the adapted wheat powdery mildew fungus while expression of the same genes did not protect barley from attack by the barley powdery mildew fungus. The results suggest that HvLEMK1 is a factor mediating non-host resistance in barley and quantitative host resistance in wheat to the wheat powdery mildew fungus.

Identification and Characterization of a Large Effect QTL from Oryza glumaepatula Revealed Pi68(t) as Putative Candidate Gene for Rice Blast Resistance

“…Malectin is a membrane-anchored protein of the endoplasmic reticulum that recognizes and binds Glc2-N-glycan. The domain is found in number of plant receptor kinases and known to play a role in defense mechanisms (Bellande et al 2017;Rajaraman et al 2016). We hypothesize that malectin transmembrane domain may receive the external cues in response to blast infection and trigger the signal transduction using the kinase domain.…”

The genetics of exapted resistance to two exotic pathogens in pedunculate oak

“…Signatures of positive selection have been reported in the malectin domain of an RLK in Populus (Fischer et al ., ), and Rajaraman et al . () demonstrated that an LRR/malectin RLK mediates resistance to nonadapted and adapted PM fungi in barley and wheat ( Triticum aestivum ).…”

Divergence between bread wheat and Triticum militinae in the powdery mildew resistance QPm.tut-4A locus and its implications for cloning of the resistance gene

“…An additional candidate is represented by Tm10 which encodes a protein containing an LRR, a MAL and a PK domain. A barley protein of this domain composition (HvLEMK1) is known to mediate non-host resistance to powdery mildew, while its wheat ortholog acts to enhance the level of wheat host resistance to powdery mildew (Rajaraman et al 2016 ). A comparison of the TaLEMK1 and the Tm10 protein sequences showed that they share only a 34% level of identity; this rather low level of homology, combined with the observations that the wheat LEMK1 homoeologs map to the group 5 chromosomes and that no Tm10 transcript was detected, rules out the possibility that the QPm.tut - 4A resistance is conferred by Tm10 .…”