Translatability of a plant-mRNA strongly influences its accumulation in transgenic plants.

Current knowledge of parameters affecting RNA stability is very restricted in plants. Here we investigated factors which might contribute to the stability of a particular plant messenger RNA. To this end, insertion and deletion mutants were made in two different exons and an intron of the transcribed region of a well characterised patatin gene (pgT5). Mutant genes were expressed under the control of a strong leaf-stem specific promoter (ST-LS1) and analysed in vivo in transgenic tobacco plants. Northern analysis revealed the importance of the translatability of the mature messenger RNA with respect to its accumulation in transgenic plants. Enlargement of the 3' non-translated region by several hundred base-pairs reduced the steady state mRNA level slightly; the introduction of a stop codon leading to premature termination of translation of the RNA led to a dramatic decrease of the steady state mRNA level.