PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

Phosphorus (P) limitation conditions could be lessened by developing oil palm progenies with increased P absorption efficiency using molecular approaches. The molecular-assisted selection method can be applied to select elite palms with high nutrient-uptake efficiency. The aim of the study was to identify key genes that were differentially expressed under P-deficient conditions. A molecular marker could be developed from the RNA-seq results. RNA-seq was applied for prolific and non-prolific genotypes grown under low- and high- P dosage for 180 days, and their specific morphological characters were also observed. Root length, shoot length, and P-content characteristics showed significant differences among genotypes under both P dosages. Heat-maps were employed to visualise the RNA sequencing results. In total, 2,905 DEGs involved in P deficiency in oil palm were identified. The GO terms were subsequently divided into 74 sub-categories. Phosphorylation, protein phosphorylation, transferring phosphorus-containing groups, alcohol group as acceptor, and nitrogenous group as acceptor were the five major subcategories related to P deficiency. Five genes were selected based on their response to P deficiency, the up-regulated genes consisted of NRR1 and AP4S1; and the down-regulated consisted of PTI/STPs, PPD7, and PPR genes. These five genes are suggested to be validated using RT-qPCR to determine their expression in the next study. Hence, this research provides a comprehensive understanding of the physiological processes involved in the oil palm seedling response to P deficiency. The results may be used for the development of biomarkers for the rapid selection of candidate palms in oil palm breeding programmes.