Enhancing Agrobacterium-mediated plant transformation efficiency through improved ternary vector systems and...

Area of Science:

• Plant Biotechnology
• Microbial Genetics
• Molecular Biology

Background:

• Agrobacterium-mediated transformation is crucial for plant functional genomics and crop improvement.
• Ternary vector systems enhance T-DNA delivery efficiency by incorporating additional virulence (vir) genes.
• Auxotrophic Agrobacterium strains aid in reducing post-cultivation bacterial overgrowth.

Purpose of the Study:

• To develop novel thymidine auxotrophic Agrobacterium strains and a new ternary helper plasmid.
• To enhance Agrobacterium-mediated plant transformation efficiency.
• To facilitate plant transformation and genome editing applications.

Main Methods:

• Generated thymidine auxotrophic strains from public Agrobacterium strains (EHA101, EHA105, EHA105D, LBA4404).
• Assessed T-DNA transfer capability using transient GUS expression assays in Arabidopsis.
• Evaluated transformation frequencies in maize immature embryos using auxotrophic strains and a new ternary helper (pKL2299A).

Main Results:

• Auxotrophic strains demonstrated thymidine-dependent growth and retained T-DNA transfer capability.
• Auxotrophic strains EHA105Thy- and LBA4404T1 showed comparable transformation frequencies to controls in maize.
• The new ternary helper pKL2299A consistently improved maize transformation frequencies (33.3% vs. 25.6%).

Conclusions:

• The developed auxotrophic Agrobacterium strains and ternary helper system effectively enhance plant transformation.
• This improved system offers a valuable tool for advancing plant biotechnology and genome editing research.
• The auxotrophic strains simplify Agrobacterium removal, streamlining the transformation process.