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.