RESUMO
BACKGROUND: Plant microRNA, often known as miRNA, is a novel form of gene expression regulator that is known to play a significant role in phosphate starvation. The identification of microRNAs involved in the response to phosphate starvation in oil palms is beneficial for breeding programs. METHOD: The main nursery stage seedlings of two oil palm progenies were treated with three different fertiliser namely: complete fertiliser with urea, P2O5, K2O, and MgO based on the standard procedure as a control (C); fertiliser with urea, K2O, MgO without P2O5 (P0); and no fertiliser (F0) for 24 weeks. A total of six oil palm roots were subjected to RNA isolation, followed by miRNA sequencing using the Illumina HiSeq 4000 platform, and all reads were computationally analysed. RESULTS: In total, 119 potential miRNAs related to 5,891 genes were identified. The P-specific miRNAs were assumed based on the miRNAs that identified without P fertilizer treatment, resulted of twenty miRNA sequences in the treatment comparison of (C vs P0) vs (C vs F0). Those 20 miRNA sequences were grouped into 9 families, namely EgmiR319; EgmiR399; EgmiR396; EgmiR172; EgmiR156; EgmiR157; miR5648; miR5645; and EgmiRNA_unidentified. Two miRNAs were selected for RT-qPCR validation, namely EgMir399 and EgMir172. Their expression pattern was similar with the RNA sequencing results and shown opposite expression pattern with their target genes, UBC E2 24 and APETALA2, respectively. CONCLUSIONS: The nine micro RNA families was identified in oil palm root tissue at phosphate starvation.
