RNA editing (RE) is a post-transcriptional modification that alters nucleotide sequences in RNA molecules, creating differences between mRNA and genomic DNA. This process occurs across various RNA species, including coding sequences, long non-coding RNAs, transfer RNAs, microRNAs, and ribosomal RNAs. Chloroplast transcript editing efficiency varies significantly across developmental stages, tissue types, and environmental conditions. However, RNA editing dynamics in Calotropis procera organellar genomes and their role in abiotic stress tolerance remain poorly characterized. This study investigated RNA editing events in C. procera plastomes under drought and light stress conditions. Plants cultivated in Jeddah desert, Saudi Arabia, were sampled at specific intervals before and after irrigation (dawn, midday, and pre-dusk). RNA sequencing and alignment against the C. procera plastome reference sequence identified RE sites, with nine editing events validated using quantitative reverse transcription PCR. Analysis revealed 117 total RE events across timepoints, encompassing four editing categories (G–A, C–T, A–G, T–C). Pre-irrigation drought stress yielded 25 RE events, increasing to 68 post-irrigations. Expected editing types (C–T, T–C) comprised 43 events, while unexpected types (G–A, A–G) accounted for 74 events. All editing events occurred within 13 plastome genes, with 29 in intergenic regions and 88 in exonic regions. qRT-PCR confirmed seven of nine tested sites. These findings demonstrate significant light and drought stress effects on plastome RNA editing patterns, providing insights into enhancing crop production efficiency under abiotic stress conditions.
N. B. S. Al-Saud (Thu,) studied this question.