Abstract
BackgroundPlant disease resistance to host-adapted pathogens is often mediated by host nucleotide-binding and leucine-rich repeat (NLR) receptors that detect matching pathogen avirulence effectors (AVR) inside plant cells. AVR-triggered NLR activation is typically associated with a rapid host cell death at sites of attempted infection and this response constitutes a widely used surrogate for NLR activation. However, it is challenging to assess this cell death in cereal hosts.ResultsHere we quantify cell death upon NLR-mediated recognition of fungal pathogen AVRs in mesophyll leaf protoplasts of barley and wheat. We provide measurements for the recognition of the fungal AVRs AvrSr50 and AVRa1 by their respective cereal NLRs Sr50 and Mla1 upon overexpression of the AVR and NLR pairs in mesophyll protoplast of both, wheat and barley.ConclusionsOur data demonstrate that the here described approach can be effectively used to detect and quantify death of wheat and barley cells induced by overexpression of NLR and AVR effectors or AVR effector candidate genes from diverse fungal pathogens within 24 h.
Highlights
Plant disease resistance to host-adapted pathogens is often mediated by host nucleotide-binding and leucine-rich repeat (NLR) receptors that detect matching pathogen avirulence effectors (AVR) inside plant cells
We show that our method proved successful for wheat, at least when overexpressing NLR/AVR pairs, as we could quantify cell death upon recognition of the stem rust fungus Puccinia graminis f. sp. tritici (Pgt) effector AvrSr50 [20] by its matching NLR Sr50 [21], both in wheat and in barley mesophyll protoplasts
We depict how mesophyll protoplasts derived from barley and wheat leaves, and possibly leaves from other cereals, can be transfected and screened for the identification and verification of pathogen effector candidates derived from two unrelated fungal pathogens
Summary
Plant disease resistance to host-adapted pathogens is often mediated by host nucleotide-binding and leucine-rich repeat (NLR) receptors that detect matching pathogen avirulence effectors (AVR) inside plant cells. Saur et al Plant Methods (2019) 15:118 molecular and genetic verification of AVR recognition by host plant NLRs, but this is challenging to evaluate in cereal hosts. The development of the method described here was motivated by the need for a method to test pathogen AVR candidates by rapidly assaying cell death mediated by matching NLR/AVR pairs in barley and wheat hosts, whilst avoiding the limitations of existing protocols. An existing method most closely resembling the natural delivery of effectors into plant host cells during pathogen infection is the delivery of pathogen effectors into resistant hosts via the bacterial type-III secretion system [5]. Successful in one case [6, 7], type III secretion of fungal AVRs into cereals is not used extensively and failed to identify Bgh AVRa1 and AVRa13 [8] for unknown reasons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
