Search for: All records

Chromosome architecture plays a crucial role in bacterial adaptation, yet its direct impact remains unclear. Different bacterial species and even strains within the same species exhibit diverse chromosomal configurations, including a single circular or linear chromosome, two circular chromosomes, or a circular-linear combination. To investigate how these architectures shape bacterial behavior, we generated near-isogenic strains representing each configuration inAgrobacterium tumefaciensC58, an important soil bacterium widely used for plant genetic transformation. Strains with a single-chromosome architecture, whether linear or circular, exhibited faster growth, enhanced stress tolerance, and greater interstrain competitiveness. In contrast, bipartite chromosome strains showed higher virulence gene expression and enhanced transient plant transformation efficiency, suggesting a pathogenic adaptation. Whole-transcriptome analysis revealed architecture-dependent gene expression patterns, underscoring the profound impact of chromosome organization onAgrobacteriumfitness and virulence. These findings highlight how chromosome structure influences bacterial adaptation and shapes evolutionary trajectories. 

SUMMARY Plant genetic transformation is essential for understanding gene functions and developing improved crop varieties. Traditional methods, often genotype‐dependent, are limited by plants' recalcitrance to gene delivery and low regeneration capacity. To overcome these limitations, new approaches have emerged that greatly improve efficiency and genotype flexibility. This review summarizes key strategies recently developed for plant transformation, focusing on groundbreaking technologies enhancing explant‐ and genotype flexibility. It covers the use of morphogenic regulators (MRs), stem cell‐based methods, andin plantatransformation methods. MRs, such as maizeBabyboom(BBM) withWuschel2(WUS2), andGROWTH‐REGULATING FACTORs(GRFs) with their cofactorsGRF‐interacting factors(GIFs), offer great potential for transforming many monocot species, including major cereal crops. OptimizingBBM/WUS2expression cassettes has further enabled successful transformation and gene editing using seedling leaves as starting material. This technology lowers the barriers for academic laboratories to adopt monocot transformation systems. For dicot plants, tissue culture‐free orin plantatransformation methods, with or without the use of MRs, are emerging as more genotype‐flexible alternatives to traditional tissue culture‐based transformation systems. Additionally, the discovery of the local wound signal peptide Regeneration Factor 1 (REF1) has been shown to enhance transformation efficiency by activating wound‐induced regeneration pathways in both monocot and dicot plants. Future research may combine these advances to develop truly genotype‐independent transformation methods.