1. A process of endowing a plant or plant cells with a trait of interest by expressing an RNA sequence of interest, said process comprising: providing plant cells or cells of said plant with a first vector and a second vector and selecting cells endowed with said trait of interest, wherein said first vector contains a first nucleotide sequence with a first segment coding, in 5′ to 3′ direction, for a 5′ part of said RNA sequence of interest and a 5′ part of an intron; and said second vector contains a second nucleotide sequence with a second segment coding, in 5′ to 3′ direction, for a 3′ part of an intron and a 3′ part of said RNA sequence of interest.