关键词: 人工染色体, 基因组工程, 植物人工染色体, 叶绿体人工染色体, 合成生物学

Abstract:

Plant artificial chromosomes (PACs) are human-designed chromosomes that can independently replicate and are stably inherited in plant cells, offering significant potential for genetic engineering. A key advantage of PACs lies in their capacity to accommodate large genetic cassettes while functioning independently of the host genome, establishing PACs as a versatile platform for stable and biosafe genetic manipulation. This review systematically outlines current strategies for PAC construction, methodologies, and future application prospects from a synthetic biology perspective. Current strategies for PAC construction are broadly categorized into top-down and bottom-up approaches. The top-down strategy utilizes endogenous chromosomal elements through techniques such as telomere-mediated chromosomal truncation (TMCT) to generate minichromosomes. In contrast, the bottom-up strategy focuses on the de novo assembly of functional elements, such as centromeres, telomeres, and autonomous replication sequences to synthesize novel chromosomes. Significant progress has also been made in developing extra-nuclear PACs based on plastid or mitochondrial genomes, which benefits from prokaryotic-like transcription and translation systems and offer higher transgene containment. However, the efficient delivery of large PAC constructs into plant cells remains a major technical hurdle. This review evaluates various delivery methodologies to address this challenge. By enabling high-capacity, chromosome-scale engineering, PACs significantly expand the scope of synthetic biology, supporting not only large-scale genomic modifications in existing species but also the de novo design of synthetic gene networks and metabolic pathways. Delivering large PAC constructs into plant cells remains a major bottleneck, and the review evaluates various methods. By enabling chromosomal-level engineering, PACs expand the scope of synthetic biology. Beyond supporting large-scale modifications in existing plants, PACs also allow the de novo assembly of novel gene networks and metabolic pathways, paving the way for engineering plant systems with novel, non-native traits and functions. To fully unleash this potential, several technical challenges must be addressed, including efficient synthesis and delivery of large DNA fragments, enhancement of genetic stability, and the integration of artificial intelligence (AI) with synthetic biology for precise design and functional optimization of PACs. Through iterative design-build-test-learn (DBTL) cycles, PACs can be developed into predictable and stable biological systems. The convergence of these approaches is expected to drive transformative applications across agriculture, pharmaceuticals, and ecology.

Key words: artificial chromosome, genome engineering, plant artificial chromosome, plastid artificial chromosome, synthetic biology