| BBa_J23100 | Pj23100 | Existing | Basic | Regulatory | 35bp |
| BBa_B0034 | B0034 | Existing | Basic | RBS | 12bp |
| BBa_250KQHPR | QscR | New | Basic | Coding | 714bp |
| BBa_B0015 | B0015 | Existing | Basic | Terminator | 28bp |
| BBa_25MBHXUL | PQscR | New | Basic | Regulatory | 300bp |
| BBa_K5281012 | TnaA | Existing | Basic | Coding | 423bp |
| BBa_K1131000 | FMO | Existing | Basic | Coding | 1377bp |
| BBa_256Z3BBH | EntC | New | Basic | Coding | 1173bp |
| BBa_252HL69L | PchB | New | Basic | Coding | 303bp |
| BBa_252ETII1 | QscR-PQscR | New | Composite | Coding | 1190bp |
| BBa_25FTS3X3 | EntC-PchB | New | Composite | Coding | 1652bp |
| BBa_257DD3ID | QscR-PQscR-TnaA-FMO | New | Composite | Coding | 4151bp |
This project aims to develop a biocontrol strategy against bacterial wilt using synthetic biology methods. For this purpose, we have specifically constructed and integrated a diverse functional gene parts library. This library contains 4 newly designed basic parts, 3 composite parts, and several existing iGEM standard parts. Together, they form a smart genetic circuit capable of sensing pathogen signals and autonomously producing the therapeutic molecule (salicylic acid), providing a novel modular solution for plant protection.
BBa_J23100 (Pj23100): This is an existing, 35bp long constitutive strong promoter, used to drive high-level, continuous gene expression.
BBa_B0034 (B0034): This is an existing, 12bp long Ribosome Binding Site (RBS), responsible for efficiently initiating the translation of genes.
BBa_250KQHPR (QscR): This is a novel, 714bp long coding sequence responsible for expressing the QscR protein, a regulatory factor that can specifically sense the quorum-sensing signal molecule AHL from Ralstonia solanacearum.
BBa_B0015 (B0015): This is an existing, 28bp long double terminator, which effectively terminates transcription and prevents read-through.
BBa_25MBHXUL (PQscR): This is a novel, 300bp long regulatory element; it is a specific promoter regulated by the QscR protein, which activates downstream gene expression upon sensing the signal.
BBa_K5281012 (TnaA): This is an existing, 423bp long coding sequence responsible for expressing tryptophanase, which participates in providing precursor molecules for the salicylic acid synthesis pathway.
BBa_K1131000 (FMO): This is an existing, 1377bp long coding sequence responsible for expressing a flavin-containing monooxygenase, a key enzyme in the catalytic synthesis of salicylic acid.
BBa_256Z3BBH (EntC): This is a novel, 1173bp long coding sequence responsible for expressing isochorismate synthase EntC, involved in the synthesis of salicylic acid precursors.
BBa_252HL69L (PchB): This is a novel, 303bp long coding sequence responsible for expressing isochorismate pyruvate-lyase PchB, which can directly catalyze the production of salicylic acid.
BBa_252ETII1 (QscR-PQscR): This composite part combines the regulatory factor QscR with its corresponding promoter PQscR, forming a core sensing switch capable of detecting and responding to Ralstonia solanacearum signals.
BBa_25FTS3X3 (EntC-PchB): This composite part is formed by fusing the coding sequences of the two enzymes EntC and PchB, designed to optimize and enhance the biosynthetic pathway for salicylic acid.
BBa_257DD3ID (QscR-PQscR-TnaA-FMO): This is a highly integrated composite part that combines the Ralstonia solanacearum sensing system with the expression of the two key enzymes TnaA and FMO, forming a complex, pathogen-signal-controlled circuit for the synthesis of the therapeutic molecule.
The parts library developed in this project, particularly the core QscR-PQscR Ralstonia solanacearum-specific sensing system, the efficient EntC-PchB salicylic acid synthesis module, and the validated TnaA and FMO combination, provides valuable resources for future iGEM teams. These characterized, standardized parts are highly modular and composable. Any subsequent team working on building biosensors for Ralstonia solanacearum or other pathogens, developing biocontrol strategies, or conducting research on the biosynthesis of salicylic acid and related therapeutic molecules can directly utilize these 'plug-and-play' parts. This will significantly simplify the process of constructing new systems, shorten project timelines, and lay a reliable foundation for developing more complex and intelligent agricultural synthetic biology applications. The ability to combine independent enzyme parts (like TnaA and FMO) with regulatory circuits is a key advantage.
