Overview
To address bacterial plant diseases and promote sustainable agriculture, CAU-China 2025 aims to build a safe, controllable, and programmable platform for synthesizing phage-like particles, PhAgri.
Through modular design, our wet lab developed a delivery system and a tail protein replacement platform to flexibly reprogram antimicrobial spectra. Our dry lab’s software- Alphage provided rational design strategies for replacing tail fiber protein. In parallel, our Human Practices aligned the project with multiple Sustainable Development Goals and original educational resources.
Wet Lab
To address the limitations of traditional pesticides and natural bacteriophages in controlling plant bacterial diseases, CAU-China 2025 designed and constructed a platform enabling the programmed, safe, and controllable production of phage-like particles within chassis bacteria.
We focused on resolving issues with natural bacteriophages in agricultural applications, including uncontrollable self-replication, narrow host range, and potential safety risks.
We deconstructed the complex life cycle of T7 bacteriophages into standardized, programmable functional modules. These modules were then rationally reconstructed and optimized in edited E. coli MG1655, ultimately establishing a highly efficient, safe, and programmable phage-like particle synthesis platform.
Development of a Novel Toxic-Plasmid Delivery System
We constructed a modular toxic-plasmid delivery system comprising the following optimized and validated components:
- T7 packaging sequence: Enables rolling-circle plasmid replication and multimeric DNA formation
- PTetA-MazF toxin module: A tightly regulated toxin expression system
- Modular tail protein expression unit: Enables flexible host-range reprogramming
These functionally validated standardized components provide reliable building blocks for future iGEM teams developing similar delivery systems.
Construction of the Innovative Genome Editing Tool pKD46-SacB
We developed the pKD46-SacB vector system, an efficient large-fragment genome integration tool featuring:
- Efficient Red recombination system and temperature-sensitive replicon
- SacB as a positive selection marker for enhanced screening efficiency
- Capability of multi-round sequential integration for large DNA fragments
This vector and its integration protocol provide reliable technical support for iGEM teams undertaking complex genome engineering projects.
Establishment of a Flexible Tail Protein Replacement Platform
- Developed a standardized tail protein replacement strategy
- Validated the functionality of heterologous tail proteins
- Modified the host range of phage-like particles while preserving their targeting specificity
This modular design enables us to generate diverse phage-like particles by swapping tail fiber genes on plasmids, thereby recognizing and eliminating various pathogenic bacteria. This approach establishes a programmable, broad-spectrum precision antibacterial platform.
Dry lab
Software
Our Alphage provides the wet lab team with rationally designed tail fiber modification strategies, effectively conserving time and resources in early-stage experimental design and trial-and-error.
Furthermore, we envision that Alphage can offer a novel and customizable suicide module solution for the broader iGEM community: by engineering a well-characterized phage (e.g., T7) and utilizing Alphage to design compatible tail fibers, teams can construct highly sensitive and tunable suicide elements for the targeted killing of specific bacterial hosts.
In this framework, Alphage serves as the foundational cornerstone for building these functional modules.
Models
The models developed by the Dry Lab consist of four parts, which correspond to the overall project design workflow, mirroring and mutually supporting the wet lab experiments.
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The Stability Model for a Dual-Plasmid System and the Metabolic Burden Analysis Model provide a basis for refining the wet lab’s experimental protocols. For other iGEMers, our analytical framework can be used as a foundation to consider the compatibility and stability of their own chassis strains and plasmid systems. Furthermore, they can expand or adapt this framework to address broader or more specific questions.
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The Protein-Protein Docking Model assesses the feasibility of tail fiber replacement. This workflow and the model itself can be generalized to evaluate the feasibility and stability of molecular docking for other proteins.
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The Infection and Inoculation Model predicts the application dosage and duration of action. Its formulas and evaluation criteria can be applied to other similar scenarios, including but not limited to, the fields of biopesticides or pollution remediation.
In summary, we hope that other iGEMers can draw inspiration from our dry lab design to advance and refine research on similar problems.
Human Practice
Integrated Efforts Towards Multiple Sustainable Development Goals (SDGs)
Our Human Practices (HP) work, centered around “swift, coordinated and decisive actions”, spans SDG 2 (Zero Hunger), SDG 4 (Quality Education), SDG 8 (Decent Work and Economic Growth), SDG 12 (Responsible Consumption and Production), SDG 13 (Climate Action), SDG 15 (Life on Land), and SDG 17 (Partnerships for the Goals).
Through the design of PhAgri, we directly contribute to ecological agriculture (SDG 2, SDG 12, SDG 15).
Our educational programs ensure the inclusiveness and equity of quality education (SDG 4, SDG 10). Meanwhile, in-depth cooperation with multiple partners has built a collaborative network covering knowledge sharing and resource integration (SDG 17), providing a replicable model for the iGEM community to practice multilateral cooperation.
Educational Game Kits: Lowering the Barrier to Synthetic Biology
CAU-China has developed the original educational game “SynBio Halli Galli”. We have contributed its complete design process, iterative insights, and final outcomes to the iGEM community. Future teams can leverage this resource in the following ways:
- Plug-and-play teaching tool:
These games can be directly used in science popularization activities. With their strong interactivity and fun, they instantly capture students’ attention and stimulate their interest in basic biology knowledge.
The card game distinguishes eukaryotic/prokaryotic components by color and shape, intuitively demonstrating the construction logic of genetic pathways.
- Reusable design methodology:
Our development went through three complete “Design-Build-Test-Learn” cycles. For instance, the evolution of card patterns from complex and indistinguishable to minimalist symbols, and the introduction of “contamination card” and “function card” mechanisms to balance scientific accuracy and fun, provide valuable and actionable experience for subsequent teams to design their own educational toys.
Open-Access Online Course Packages for Inclusive Education
We have created and released a series of open-access science popularization course packages online, including the widely acclaimed picture book course A Synthetic Biology Journey of Chocolate, as well as thematic courses that deeply integrate SDG 13 (Climate Action), SDG 14 (Life Below Water), and SDG 15 (Life on Land).
Based on our work, future iGEM teams can:
- Promote educational equity:
Through distance teaching, these course packages can be directly applied to online education in remote areas, effectively addressing the challenges of insufficient local science popularization resources and inconvenient offline teaching, just as we practiced in Dali Gusheng Primary School.
- Flexibly adapt to teaching needs:
The course packages include PPTs, teaching videos, and feedback forms, with a clear structure and complete content. Subsequent teams can freely select content modules and teaching formats according to their own project backgrounds or target audiences, greatly reducing the threshold for preparing high-quality science popularization courses.
- Draw on effective teaching strategies:
What we contribute is not only content, but also the verified effectiveness of our design through first-hand educational practice. All these activities provide key insights for future teams to design courses for younger audiences.