FUNGUY
Symbiotic and pathogenic fungi may use similar molecular tools to manipulate plants
Comparing plant pathogenic fungi and plant symbiotic fungi, scientists at the Sainsbury Laboratory Cambridge University (SLCU) have discovered that these remote relatives are using a similar group of proteins to manipulate and live within plants
Peer-Reviewed PublicationIMAGE: MODELS OF THE STRUCTURES OF FOLD PROTEINS FROM A PATHOGEN (BLUE) AND A SYMBIOTIC FUNGUS (ORANGE) SUPERIMPOSED ONTO EACH OTHER TO SHOW HOW SIMILAR THEY ARE. IMAGE BY ALBIN TEULET view more
CREDIT: ALBIN TEULET
Symbiotic and pathogenic fungi that interact with plants are distantly related and don’t share many genetic similarities. Comparing plant pathogenic fungi and plant symbiotic fungi, scientists at the Sainsbury Laboratory Cambridge University (SLCU) have discovered that these remote relatives are using a similar group of proteins to manipulate and live within plants.
Sebastian Schornack’s research team is working to identify and characterise new arbuscular mycorrhiza (AM) effectors – proteins secreted by symbiotic AM fungi to facilitate colonisation of plant roots. As part of this they are also investigating whether pathogenic and symbiotic fungi are using similar or different strategies.
Using the AlphaFold2 AI computer programme that predicts protein structures, the team is the first to compare secreted proteins from symbiotic and pathogenic fungi. They found that symbiotic fungi encode the same family of proteins that pathogenic fungi use to interact with and colonise plants. The findings were published today in New Phytologist.
“There is a huge diversity in the genetic code of effector proteins in closely related microbes, so it is even more difficult to compare protein sequences between pathogens and symbionts that are more distantly related,” said Dr Albin Teulet, who is first author of the research. “Instead, we took advantage of the recent development of AlphaFold2 to do a comparison between the secreted protein structures from a symbiotic fungus and pathogenic fungus. This led to the discovery that there is a group of structurally very similar proteins previously known from pathogens that are also present – often in greater numbers – encoded in the genomes of symbiotic fungi.”
Plant-fungi relationships have a dramatic effect on plant health in natural ecosystems and agriculture – both positive and negative. AM fungi are the most common symbiotic association of plants with microbes, colonising plant roots to promote nutrient uptake, enhance plant growth and even help fend off pathogens. While pathogenic fungi, such as strains of Fusarium oxysporum, are some of the world’s most devastating pathogens with a wide host range and are currently threatening to wipe-out Cavendish banana and oil palm plantations. Fusarium also has lent its name to the group of proteins the team have found: Fusarium oxysporum lycopersici dual-domain proteins (FOLDs).
The researchers classified all the proteins secreted by the symbiotic AM fungus Rhizophagus irregularis and identified a large family of FOLD-like effectors (MycFOLDs) with high structural similarity to the FOLD proteins produced by the Fusarium oxysporum pathogen.
FOLD effectors are only found in the genomes of fungi that form associations with living plants. This suggests that these proteins underpin universal mechanisms enabling both pathogens and symbiotic fungi to live within plants.
Dr Schornack said discovering that plant symbiotic and pathogenic fungi were using some of the same tools provided a new perspective on our understanding of fungal symbionts: “The apparently exclusive presence of FOLD/MycFOLDs across unrelated plant-colonising fungi supports the hypothesis that FOLD proteins act as effectors during plant colonisation of both symbiotic and pathogenic fungi.”
“If symbiotic and pathogenic fungi are using the same tools, this means devising ways to enhance AM relationships in crops might make the crops more susceptible to pathogens at the same time. However, these findings now open new questions for us to explore, such as why do symbiotic fungi have these proteins that pathogens also have and what do they actually do?”
Detection of gene activity of a FOLD gene (black spots) specifically in the structures formed by the symbiotic fungus Rhizophagus irregularis (labelled in yellow) within legume root cells. Image by Edouard Evangelisti.
CREDIT
Edouard Evangelisti
The fundamentals of plant-microbe interactions Understanding the similarity and diversity of effectors used by symbionts and pathogens is critical to understanding the fundamentals of plant-microbe interactions. The plant-pathogen relationship has been well studied with many of the effector proteins already known. However, less is known about plant-symbiont interactions, like those between plants and AM fungi. Plants that form beneficial relationships with symbiotic fungi control all stages of the colonisation – they can reject or expel colonisers if they deem the fungal colonisation not necessary, such as in soil environments with plentiful supplies of nutrients like phosphate. However, AM fungi are dependent on plant-produced nutrients and thus also have their own survival strategy, particularly in cases where the relationship is unwanted by the plant. During the infection process, pathogenic fungi supress their plant host’s immunity by secreting a cocktail of effector proteins. Even though symbiotic fungi are beneficial to plants, they too must communicate with the plant or overcome barriers to successfully colonise plant cells. Only a small number of effector proteins secreted by symbiotic AM fungi have been identified. The Schornack Team is working to uncover other effectors that play a role in the plant-symbiont relationship. |
Funding
This research was funded by the Gatsby Charitable Foundation, the Royal Society and by the European Research Council.
About the Sainsbury Laboratory Cambridge University (SLCU)
SLCU is a research institute funded by the Gatsby Charitable Foundation within the School of Biological Sciences. The Laboratory is focused on increasing understanding of the regulatory systems underlying plant growth and development. It brings together specialists in biological, physical, and mathematical sciences integrating a range of wet-lab experimental research with computational modelling. This interdisciplinary approach is essential for understanding the complex dynamic and self-organising properties of plants.
About New Phytologist
New Phytologist is a leading international journal focusing on high quality, original research across the broad spectrum of plant sciences, from intracellular processes through to global environmental change. The journal is owned by the New Phytologist Foundation, a not-for-profit organisation dedicated to the promotion of plant science.
https://www.newphytologist.org/
JOURNAL
New Phytologist
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
A pathogen effector FOLD diversified in symbiotic fungi. New Phytologist
ARTICLE PUBLICATION DATE
31-May-2023
Fungus has a host of issues
KyotoU discovers how toxic fungi target specific host plants
Peer-Reviewed PublicationIMAGE: CUCUMBER LEAF, ALONG WITH MELON AND TENTH, ARE STUDIED FOR THE EFFECTOR PROTEINS EPC1 TO EPC4. view more
CREDIT: KYOTOU TOBIYAMA/YOSHITAKA TAKANO
Kyoto, Japan -- While infectious fungal plant diseases relentlessly wreak havoc on many crops, they are also picky when choosing their hosts. Each fungus generally exhibits a specific host range, but the mechanism of this specificity has not been well understood.
Kyoto University researchers have now identified and categorized four fungal proteins called effectors responsible for suppressing host plant immunity from infection.
Phytopathogens are plant pathogenic fungi that secrete these effectors. As a result, the harmful fungus generally exhibits distinct host specificity when infecting plants, causing more than 70% of plant diseases.
According to the researchers, the four effector proteins named EPC1 to EPC4 in Colletotrichum orbiculare -- a phytopathogenic fungus -- establish specificity on a host cucumber.
"The four effectors have very different amino acid sequences, suggesting that they work independently, but we need to continue analyzing the function of each effector to get a clearer picture," says lead author Yoshitaka Takano of KyotoU's Graduate School of Agriculture.
Takano's team used functional analysis -- targeted gene disruption -- on effector-like genes, which are highly expressed in six isolates of the inoculated pathogen.
"We have just cracked open a peephole to understand how effectors of phytopathogenic fungi shape host specificity. Our growing knowledge may lead to new crop protection technologies."
Deletion of four genes (EPCI to EPC4) reduced pathogen virulence From left to right: cucumber host, melon host, and benth host
CREDIT
KyotoU/Yoshitaka Takano
The paper "Selective deployment of virulence effectors correlates with host specificity in a fungal plant pathogen" appeared on 20 March 2023 in New Phytologist, with doi: 10.1111/nph.18790
About Kyoto University
Kyoto University is one of Japan and Asia's premier research institutions, founded in 1897 and responsible for producing numerous Nobel laureates and winners of other prestigious international prizes. A broad curriculum across the arts and sciences at undergraduate and graduate levels complements several research centers, facilities, and offices around Japan and the world. For more information, please see: http://www.kyoto-u.ac.jp/en
JOURNAL
New Phytologist
METHOD OF RESEARCH
Experimental study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Selective deployment of virulence effectors correlates with host specificity in a fungal plant pathogen
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