Taraxacum kok-saghyz: From emergency wartime crop to synthetic biology platform – A comprehensive review of natural rubber biosynthesis, genetic engineering, and agricultural development

Natural rubber (NR) is an irreplaceable material for over 40,000 products, yet 95% of global supply depends on a single tropical species, Hevea brasiliensis, creating unprecedented vulnerabilities from disease, climate change, and geopolitical instabilities. Taraxacum kok-saghyz (TKS), or Russian dandelion, represents the most promising temperate-zone alternative, containing 3–12% rubber in roots with molecular structure identical to Hevea rubber. This comprehensive review integrates TKS research spanning nine decades—from emergency wartime cultivation (1931–1950) to modern synthetic biology applications. Multi-omics approaches have collectively elucidated the TKS rubber biosynthetic pathway, encompassing the mevalonate (MVA) pathway that generates the isopentenyl pyrophosphate (IPP) monomer precursor, three core biosynthetic genes (CPT, REF, and SRPP), and the regulatory networks governing rubber accumulation. CRISPR/Cas9 genome editing achieved up to 88.9% mutation efficiency; simultaneous knockout of the two principal inulin biosynthesis genes, Tk1-SST and Tk1-FFT, redirected carbon flux from inulin toward rubber, more than doubling root rubber content. Eight cycles of recurrent selection demonstrated 84% yield improvement, though current production (32–750 kg/ha) remains below economic thresholds (1000–1500 kg/ha). Persistent agronomic challenges include poor seedling germination (field establishment rates frequently below 40% under suboptimal temperature conditions), slow first-year vegetative growth, complex lateral root architecture that impedes mechanical harvest, and metabolic competition between rubber and inulin biosynthesis for shared carbon substrates. This review synthesizes fragmented knowledge across disciplines, identifies critical bottlenecks, and proposes integrated strategies combining genomic selection, metabolic engineering, and agronomic optimization. Successful TKS development would diversify global rubber supply chains, enhance agricultural resilience, and provide a model for rapid crop domestication using modern biotechnology.