Excision of the maize transposable element Ac in flax callus

Area of Science:

• Plant molecular biology
• Genetics
• Transposable elements research

Background:

• The Ac/Ds system is a well-studied model for transposon activity in plants.
• Understanding transposition frequency and fidelity is crucial for genetic engineering and crop improvement.

Purpose of the Study:

• To investigate the frequency and fidelity of Ac (activator) and Ds (dissociation) element transposition in flax (Linum usitatissimum).
• To analyze the excision and potential reintegration of these elements in transformed flax callus.

Main Methods:

• Flax hypocotyls were transformed using Agrobacterium Ti plasmid vectors carrying Ac or Ds elements.
• The elements were inserted within the untranslated leader sequence of a chimaeric neomycin phosphotransferase II gene.
• Kanamycin resistance was used as a readout for successful excision events.

Main Results:

• Ac element excision was observed in approximately 35% of Ac-containing transformants.
• No excision events were detected for the Ds element in the tested transformants.
• Evidence suggests complete excision of Ac from T-DNA, with minimal indication of genomic reintegration.

Conclusions:

• The Ac element exhibits significant, albeit incomplete, transposition activity in flax callus.
• The non-autonomous Ds element appears inactive under these experimental conditions.
• Further studies are needed to fully elucidate the reintegration mechanisms of Ac in the flax genome.