Related Experiment Video
Updated: Jul 13, 2025
07:36
Visualizing Early Infection Sites of Rice Blast Disease Magnaporthe oryzae on Barley Hordeum vulgare Using a Basic Microscope and a Smartphone
Published on: March 17, 2023
1.7K
Barley MLA3 recognizes the host-specificity effector Pwl2 from Magnaporthe oryzae
Helen J Brabham1,2, Diana Gómez De La Cruz1, Vincent Were1
1The Sainsbury Laboratory, University of East Anglia, Norwich Research Park, Norwich NR4 7UH, UK.
The Plant Cell
|October 11, 2023
Summary
The barley Mla3 immune receptor recognizes effectors from both powdery mildew and rice blast fungus. This study reveals Mla3
Area of Science:
- Plant immunity
- Molecular plant pathology
- Genetics
Background:
- Plant nucleotide-binding leucine-rich repeat (NLRs) are immune receptors that detect pathogen effectors.
- Most NLRs recognize effectors from a single pathogen species, with few exceptions.
- Barley (Hordeum vulgare) Mla alleles confer resistance to powdery mildew (Blumeria graminis f. sp. hordei [Bgh]).
Purpose of the Study:
- To investigate the functional range of the barley Mla3 NLR immune receptor.
- To determine if Mla3 can recognize effectors from pathogens beyond barley powdery mildew.
- To identify the specific effector recognized by Mla3 from the rice blast fungus (Magnaporthe oryzae).
Main Methods:
- Forward genetic screen in barley to identify mutations affecting Mla3-mediated resistance.
- Resistance assays using barley transformed with Mla3 and challenged with Magnaporthe oryzae.
- Effector identification through genetic analysis and functional assays.
Main Results:
- Mla3 confers dosage-dependent resistance to the rice blast fungus Magnaporthe oryzae.
- The recognized effector from M. oryzae was identified as Pathogenicity toward Weeping Lovegrass 2 (Pwl2).
- Pwl2 is a host range determinant, indicating Mla3 recognizes a virulence factor.
Conclusions:
- The barley Mla3 NLR has convergently evolved to recognize effectors from evolutionarily distant pathogens, including Bgh and M. oryzae.
- This broad recognition broadens the understanding of NLR immune receptor function and evolution.
- Mla3 represents a rare example of a single NLR conferring resistance to multiple pathogens via distinct effectors.
