Commonly used gene cloning vector in plant genetic engineering is 

The tumor inducing (Ti) plasmid of Agrobacterium tumifaciens has been modified into a cloning vector which is no more pathogenic to the plants but is still able to use the mechanisms to deliver genes of our interest into a variety of plants. Other vectors such as plasmids of other bacteria, retroviruses are not used for transfer of genes and cloning them in plant cells.