Sunflower (Helianthus annuus L.)

Area of Science:

• Plant Biotechnology
• Crop Improvement
• Molecular Biology

Background:

• Sunflower (Helianthus annuus L.) exhibits significant recalcitrance in genetic transformation and regeneration.
• Efficient gene delivery and competent cell cultures are essential for developing a routine transformation system in sunflowers.

Purpose of the Study:

• To establish a robust Agrobacterium tumefaciens-mediated transformation system for sunflower (Helianthus annuus L.).
• To optimize gene delivery and regeneration protocols for recalcitrant sunflower genotypes.

Main Methods:

• Utilized split mature embryonic axis explants from the Ha89 sunflower genotype.
• Employed Agrobacterium tumefaciens strains (EHA105 or C58) with plasmids containing genes of agronomic interest.
• Confirmed transgene integration and inheritance using PCR and Southern blot analysis.

Main Results:

• Achieved a mean transformation efficiency ranging from 1% to 5.2% depending on the Agrobacterium strain used.
• Demonstrated the system's applicability with various Agrobacterium strains and plasmids, including reporter and agronomic genes.
• Confirmed stable transgene inheritance up to the T4 generation in independent sunflower lines.

Conclusions:

• Successfully developed a functional Agrobacterium-mediated transformation system for sunflower (Helianthus annuus L.).
• The established protocol facilitates efficient gene delivery and regeneration, overcoming recalcitrance in this crop.
• This system provides a valuable tool for genetic improvement and research in sunflowers.