The introduction of a fungus-originated lip H8 confers higher gene transformation efficiency of Agrobacterium fabrum in Nicotiana benthamiana.

Agrobacterium is a genus of bacteria commonly used for transgenic plant production. Transgenic efficiency of Agrobacterium is influenced by virulence (vir) gene expression, host immune responses, etc. Here, we introduced a lignin peroxidase gene lip H8 (derived from Phanerodontia chrysosporium), into Agrobacterium strain C58 - a parental strain of widely used transgenic tools. When fused with an A. fabrum signal peptide, LiP H8 was successfully synthesized and secreted extracellularly by the recombinant A. fabrum C58 strain. Lip H8 not only slightly promoted the growth of A. fabrum C58 in a nutrient-rich medium but also significantly enhanced its tolerance to H2O2 in the presence of lignin. Furthermore, the introduction of lip H8 into A. fabrum C58 significantly increased the expression of vir genes when H2O2 and lignin were present. The tumorigenesis and colonization ability of A. fabrum C58 on potato, kalanchoe, and Nicotiana benthamiana were also strengthened by the introduction of lip H8. The transient expression was investigated using the disarmed strain EHA105 (derived from A. fabrum strain C58), which, when engineered to express lip H8, showed a 31% increase in transformation efficiency in Nicotiana benthamiana. Importantly, with the introduction of lip H8, the stable transformation efficiency of A. fabrum in Nicotiana benthamiana was also significantly increased, indicating that lip H8 has great potential as a gene for Agrobacterium improvement. The underlying mechanism through which lip H8 improves transformation efficiency in Nicotiana benthamiana points to its broad application potential in recalcitrant plant species.