Short communicationA simple and efficient in planta transformation method for pommelo (Citrus maxima) using Agrobacterium tumefaciens

- Tissue culture dependent transformation needs certain requirements such as specialized equipment, extra added phytohormones and high qualified personnel.
- It has been reported that the transformation efficiency of in planta transformation could be much higher than conventional tissue culture-dependent transformation.
- Up to now, however, there is no report available on successful in planta transformation of citrus.
- In this study, a simple and efficient Agrobacterium-mediated in planta transformation protocol for Citrus maxima was established.
- The protocol developed in the present study would be useful for citrus genetic breeding and improvement.

A simple and efficient transformation method is important for plant genetic breeding and gene function analysis. In this study, we developed a in planta transformation approach for pommelo (Citrus maxima), which includes seed germination, seedling decapitation, Parafilm funnel-type-winding, Agrobacterium infection, co-culture, selective-culture, dark treatment for buds induction, transgene integration confirmation and transgenic plant propagation. The highest transformation efficiency (20.41%) was obtained when using hygromycin as selection marker, followed by Basta (19.37%) and Kanamycin (3.21%). Transgenic plants obtained using this method could be graft-propagated in 3 months post transformation, which is shorter than the tissue-culture-dependent transformation. The transformation protocol presented here has great potential to be used for citrus genetic breeding and improvement.