Improved efficiency of the walnut somatic embryo gene transfer system

Area of Science:

• Plant Biotechnology
• Molecular Biology
• Agricultural Science

Background:

• Agrobacterium-mediated transformation is crucial for developing transgenic plants.
• Efficient regeneration of transgenic walnut (Juglans regia) plants is challenging.
• Early screening methods are needed to accelerate the selection of transformed plantlets.

Purpose of the Study:

• To enhance the efficiency of Agrobacterium-mediated gene transfer for regenerating transgenic walnut plants.
• To optimize the selection process for transformed walnut embryos using marker genes.
• To reduce the time required for identifying genetically modified walnut lines.

Main Methods:

• Utilized Agrobacterium tumefaciens strain EHA101 with plasmids pCGN7001 and pCGN7314.
• Employed repetitive embryogenesis for plant regeneration.
• Incorporated kanamycin resistance and beta-glucuronidase (GUS) reporter genes for selection and screening.

Main Results:

• A more virulent Agrobacterium strain and specific vectors improved transformation efficiency.
• The GUS marker gene enabled early identification of transformed embryos within 5-6 weeks.
• Kanamycin selection on medium post-co-cultivation increased the number of transformed secondary embryos.
• 70% of GUS-positive lines originated from EHA101/pCGN7314 on kanamycin medium.

Conclusions:

• The optimized Agrobacterium-mediated system significantly accelerates the generation of transgenic walnut plants.
• The combined use of kanamycin resistance and GUS reporter genes streamlines the selection and identification process.
• This improved method facilitates faster development of genetically modified walnut varieties.