posted on 2021-06-07, 16:34authored byEftychios Frangedakis, Fernando Guzman-Chavez, Marius Rebmann, Kasey Markel, Ying Yu, Artemis Perraki, Sze Wai Tse, Yang Liu, Jenna Rever, Susanna Sauret-Gueto, Bernard Goffinet, Harald Schneider, Jim Haseloff
Chloroplasts are
attractive platforms for synthetic biology applications
since they are capable of driving very high levels of transgene expression,
if mRNA production and stability are properly regulated. However,
plastid transformation is a slow process and currently limited to
a few plant species. The liverwort Marchantia polymorpha is a simple model plant that allows rapid transformation studies;
however, its potential for protein hyperexpression has not been fully
exploited. This is partially due to the fact that chloroplast post-transcriptional
regulation is poorly characterized in this plant. We have mapped patterns
of transcription in Marchantia chloroplasts. Furthermore,
we have obtained and compared sequences from 51 bryophyte species
and identified putative sites for pentatricopeptide repeat protein
binding that are thought to play important roles in mRNA stabilization.
Candidate binding sites were tested for their ability to confer high
levels of reporter gene expression in Marchantia chloroplasts,
and levels of protein production and effects on growth were measured
in homoplastic transformed plants. We have produced novel DNA tools
for protein hyperexpression in this facile plant system that is a
test-bed for chloroplast engineering.