Project description:We previously reported that ribosome stalling at AUG-stop sequences in the 5'-UTR plays a critical role in regulating the expression of Arabidopsis thaliana NIP5;1, which encodes a boron uptake transporter, in response to boron conditions in media. Here, we conducted ribosome profiling analysis to reveal the genome-wide regulation of translation in response to boron conditions in A. thaliana. We identified 460 translationally regulated genes. Transcripts with reduced translation efficiency were rich in upstream open reading frames (uORFs), highlighting the importance of uORF-mediated translational regulation. We found that 148 uORF instances had greater ribosome density under high boron conditions. Moreover, translationally downregulated transcripts were rich in minimum uORFs (AUG-stops), suggesting that AUG-stops play a global role in the boron response. Boron increased the ribosome occupancy of stop codons, indicating that this element is involved in global translational termination processes.
Project description:Boron is an essential micronutrient for plants and is taken up in the form of boric acid (BA). Despite this, a high BA concentration is toxic for the plants, inhibiting root growth and is thus a significant problem in semi-arid areas in the world. In this work, we report the molecular basis for the inhibition of root growth caused by boron. We used microarrays to detail the global gene expression underlying boron toxicity in roots. 5-day-old arabidopsis plants were transferred to medium with high boron concentration (½ MS medium supplemented with 5mM BA) and control conditions (½ MS medium). We determined that 5 mM BA is the minimum concentration that produces the maximum effect, stunting root growth by ~50% after 5 days as compared with control conditions. We analyzed the transcript profiles in roots by microarray analysis (Affymetrix ATH1 Genome Array). We compared the transcripts obtained at 12 hrs of BA treatment.
