Chinese scientists have created an AI-guided platform to engineer custom plant immune receptors to rapidly combat emerging diseases that threaten plants, including commercial crops vulnerable to devastating outbreaks.
Their programmable synthetic immune receptors can be introduced into plants to help them detect proteins made by specific bacteria, viruses and fungi, triggering an immune response to neutralise the threat, according to the team.
By leveraging protein design guided by artificial intelligence (AI), custom receptors could be engineered within weeks rather than years, fast-tracking the breeding of disease-resistant crops and enabling a quicker response to emerging plant diseases, the researchers said.
“This work establishes a versatile platform for efficient plant immunity engineering,” the team from the Chinese Academy of Sciences’ Institute of Genetics and Developmental Biology and biotechnology company Qi Biodesign said in a paper published in the peer-reviewed journal Science last month.
Around the world, essential crops are threatened by plant pathogens that can devastate agricultural yields and compromise global food security.
Plant breeding programmes often introduce resistance genes that encode receptors capable of recognising proteins secreted by pathogens. When these receptors bind to their protein target, it can trigger an immune response.
“However, this resistance is often rapidly overcome by fast-evolving pathogens, particularly in modern agricultural systems characterised by large-scale monoculture of genetically uniform crops,” the team said.
This biological vulnerability is what heightens the threat of agro-terrorism and plant bioweapons, or pathogens purposefully introduced or modified to target specific crops.
To counter new pathogens, receptors must be identified to engineer more resistant plant varieties. However, this process can take years, as the limited diversity of natural plant immune receptors makes the process difficult and time-consuming.
Synthetic immune receptors offer a way to accelerate the development of disease-resistant crops. Instead of years, the rapid design of synthetic receptors could enable the “rapid recognition of new and emerging pathogen proteins within weeks”.
“To address the vast diversity of pathogens, we aimed to develop a universal strategy for engineering synthetic immune receptors that can recognise specific pathogen proteins.”
To create their synthetic receptor, the team spliced AI-designed proteins – which act as binders to pathogen proteins – into a natural rice immune receptor.
“These synthetic receptors successfully conferred recognition and immune activation against proteins from diverse plant pathogens, including 14 viruses, two bacteria, a fungus and an oomycete,” they said. Oomycetes are fungus-like micro-organisms that can cause destructive plant diseases.
The team said it tested 391 synthetic receptors and found that about 18 per cent triggered robust and specific immune responses, about 58 per cent displayed varying levels of autoimmunity and nearly 24 per cent showed no immune activity against targets.
Some of the pathogens that the receptors worked against target vital crops such as potatoes and tomatoes.
According to the paper, a lack of immune activity could result from improper protein expression in the plants, failure of the designed binders to engage with their target pathogen proteins, or an inability to trigger the conformational changes – or physical shape – needed to induce immune activation.
“Nevertheless, the overall design success rate was encouraging and demonstrated the broad applicability of our synthetic receptor strategy for enabling recognition of diverse pathogen-derived proteins,” the team wrote.
As crops are often threatened with infections by multiple pathogens, the team also developed a strategy to stack synthetic receptors which it said “offers a scalable and multiplexed framework for engineering broad-spectrum and durable disease resistance in crops”.
“The establishment of synthetic plant immune receptors will open new avenues for synthetic plant immunity and provide a versatile foundation for engineering disease resistance against diverse pathogens in crops.”
The team said designing synthetic receptors for certain kinds of pathogens could still be challenging, and that the overall success rate was still low, but that identifying new natural receptor scaffolds to graft binders onto and expanding AI-guided binder design could improve the system.
Source: www.scmp.com
