Production and characterisation of transgenic cauliflower plants containing abnormal chloroplasts

• Overexpression of plastid division genes in transgenic cauliflower plants.
• Honey-comb shaped chloroplasts and irregular membrane shaped chloroplasts are produced due to insufficient total increase of BoMinD protein.
• Cauliflower plastid division gene, BoMinD functions similarly to Arabidopsis plastid division gene, AtMinD1.

Macrochloroplasts, which can be produced by the imbalance expression of plastid division genes, may act as an alternative target tissue for the transformation of foreign genes especially by particle bombardment. This paper reports the production of stable transgenic cauliflower plants expressing cauliflower plastid division gene, BoMinD by using PEG mediated transformation of mesophyll protoplasts. Stable transgenic BoMinD cauliflower plants had abnormally shaped chloroplasts but these did not exhibit a true macrochloroplast or minichloroplast phenotype. Transgene number did not relate to the expression of the BoMinD transgene. Detection of total BoMinD by western blot suggests that the slight increase in total BoMinD levels resulted in honey-comb or doughnut shaped chloroplasts and irregular surface membrane chloroplasts.