- Home
- CALS News
- CALS Research
CALS Research
Novel pathogenic mechanism of plant fungal pathogens
Translocation mechanism of nuclear effector of the rice blast fungal pathogen in the host
Every year, crop losses due to plant diseases account for 30% of the global harvest. In particular, rice blast, which affects rice, causes food losses equivalent to what could feed 60 million people annually, making it one of the most important diseases with significant socio-economic impact.
To control rice blast, resistant varieties and chemical fungicides have been used, but with the increasing frequency of new pathogen strains and fungicide-resistant strains, there is a growing need for environmentally friendly and sustainable plant disease control methods.
Plant pathogens co-evolve with their host plants and secrete pathogenic proteins known as effectors to suppress the host plant's immune response. Molecular understanding of effectors is a crucial research area for elucidating the pathogenic mechanisms of pathogens, and thus, many studies are being conducted worldwide.
Among pathogen effectors, nuclear effectors are secreted by the pathogen and move into the host plant's nucleus, where they play a role in regulating the plant's immune response. This was first revealed by our research team (Nature Communications 11:5845, 2020). However, the exact mechanism by which nuclear effectors translocate into the host plant's nucleus has not yet been clarified.
A research team led by Professor Emeritus Lee Yong-hwan from the Department of Agricultural Biotechnology at Seoul National University has for the first time elucidated the mechanism by which the nuclear effector MoHTR1 of the rice blast fungus translocates into the host plant's nucleus.
The research team identified the essential nuclear localization sequence (NLS) required for the nuclear effector MoHTR1 to translocate into the host plant's nucleus. Through various molecular biology experiments, they confirmed that this nuclear localization sequence also enables the translocation of cytoplasmic effectors of the rice blast fungus into the nucleus.
The nuclear localization sequence (NLS) of the nuclear effector MoHTR1 was found not only in other rice blast fungus effectors but also in various rice proteins, which were shown to localize in the nucleus within the cell. These findings demonstrate that the NLS of MoHTR1 plays an important role in the nuclear translocation of various proteins.
It was also revealed that for MoHTR1 to translocate into the host plant's nucleus, it must be stabilized through a protein modification process (SUMOylation) and interact with the plant’s importin proteins.
Therefore, the research team utilized various molecular biology and bioinformatics techniques to uncover the nuclear localization sequence of MoHTR1, its protein modification process, and its interaction with host plant importins, ultimately elucidating for the first time how the nuclear localization sequence regulates the pathogenicity of the pathogen and the immune response of the plant.
These research findings will provide a new platform for elucidating not only the pathogenic mechanisms of rice blast fungus but also those of other plant pathogenic fungi.
This study was supported by the National Research Foundation of Korea and was published on November 11 in Nature Communications (2024 IF=14.7), a prestigious journal in the interdisciplinary research field.
(A) Observation of the location change in the host plant protoplasts due to substitution of the MoHTR1 nuclear localization sequence.
(B) Observation of the location change of the rice blast fungus cytoplasmic effector due to the MoHTR1 nuclear localization sequence.
The area marked with an arrow represents the plant nucleus, and the area marked with an arrowhead indicates the site where the effector is secreted.
Every year, crop losses due to plant diseases account for 30% of the global harvest. In particular, rice blast, which affects rice, causes food losses equivalent to what could feed 60 million people annually, making it one of the most important diseases with significant socio-economic impact.
To control rice blast, resistant varieties and chemical fungicides have been used, but with the increasing frequency of new pathogen strains and fungicide-resistant strains, there is a growing need for environmentally friendly and sustainable plant disease control methods.
Plant pathogens co-evolve with their host plants and secrete pathogenic proteins known as effectors to suppress the host plant's immune response. Molecular understanding of effectors is a crucial research area for elucidating the pathogenic mechanisms of pathogens, and thus, many studies are being conducted worldwide.
Among pathogen effectors, nuclear effectors are secreted by the pathogen and move into the host plant's nucleus, where they play a role in regulating the plant's immune response. This was first revealed by our research team (Nature Communications 11:5845, 2020). However, the exact mechanism by which nuclear effectors translocate into the host plant's nucleus has not yet been clarified.
A research team led by Professor Emeritus Lee Yong-hwan from the Department of Agricultural Biotechnology at Seoul National University has for the first time elucidated the mechanism by which the nuclear effector MoHTR1 of the rice blast fungus translocates into the host plant's nucleus.
The research team identified the essential nuclear localization sequence (NLS) required for the nuclear effector MoHTR1 to translocate into the host plant's nucleus. Through various molecular biology experiments, they confirmed that this nuclear localization sequence also enables the translocation of cytoplasmic effectors of the rice blast fungus into the nucleus.
The nuclear localization sequence (NLS) of the nuclear effector MoHTR1 was found not only in other rice blast fungus effectors but also in various rice proteins, which were shown to localize in the nucleus within the cell. These findings demonstrate that the NLS of MoHTR1 plays an important role in the nuclear translocation of various proteins.
It was also revealed that for MoHTR1 to translocate into the host plant's nucleus, it must be stabilized through a protein modification process (SUMOylation) and interact with the plant’s importin proteins.
Therefore, the research team utilized various molecular biology and bioinformatics techniques to uncover the nuclear localization sequence of MoHTR1, its protein modification process, and its interaction with host plant importins, ultimately elucidating for the first time how the nuclear localization sequence regulates the pathogenicity of the pathogen and the immune response of the plant.
These research findings will provide a new platform for elucidating not only the pathogenic mechanisms of rice blast fungus but also those of other plant pathogenic fungi.
This study was supported by the National Research Foundation of Korea and was published on November 11 in Nature Communications (2024 IF=14.7), a prestigious journal in the interdisciplinary research field.
(A) Observation of the location change in the host plant protoplasts due to substitution of the MoHTR1 nuclear localization sequence.
(B) Observation of the location change of the rice blast fungus cytoplasmic effector due to the MoHTR1 nuclear localization sequence.
The area marked with an arrow represents the plant nucleus, and the area marked with an arrowhead indicates the site where the effector is secreted.
