Analisis Transkriptomik Tanaman Kamper (Dryobalanops aromatica) yang Ditumbuhkan pada Media Gambut dan Tanah Mineral

Abstract

Dryobalanops aromatica is a highly economic value resin-producing tree. It has been known as an essential international trade commodity widely used in the perfume, cosmetics, medicine, and wood industries. In natural habitats, this adaptive species has been found to grow well on peatland and mineral soils. The information regarding adaptive genes in Indonesian native trees to abiotic stress is still very limited. The research was conducted to analyse the differential gene expression (DGEs) that can elucidate the role of several up-regulated and down-regulated genes under peat media and mineral soil treatments. DGE analysis was carried out using R software, Bioconductor package 'edgeR'. Using the Benjamini and Hochberg approach to control FDR (false discovery rate) with the value of FDR is 0.05), with a log2FC (log2 fold change) with minimal value 2 and p-value of 0.05, showed 320 contigs were up-regulated, and 439 contigs were down-regulated, while 58129 contigs were not significantly expressed. Furthermore, this study also presents an overview of the genes involved in different pathways, such as photosynthesis, carbon and energy metabolism, phytohormone-related genes, nitrogen metabolism, reactive oxygen species, and transcription factor. This information will be helpful in understanding D. aromatica molecular responses to stress conditions that may be useful for selecting genotypes in the breeding programs or peatlands restoration. We found that genes involved in plant stress phytohormone biosynthesis, such as JA (jasmonic acid), ET (ethylene), GB (gibberellic acid), were up-regulated. In contrast, genes involved in ABA and IAA showed down-regulated on peat media treatment. Further, genes encode biological functions of the cell wall, and molecular functions as metal ion binding were up-regulated. Genes that function as antibiotics and ROS scavengers such as Peroxidase and Superoxide dismutase [Fe]2, chloroplastic were also found up-regulated. The transcription factors MYB26, NAC43, and NAC73 are thought to be transcription factors involved in the defense responses to D. aromatica in peat stress treatment. Molecular phylogeny analysis was carried out on the sequences of genes related to the adaptability of D. aromatica to the peat media stress to determine the evolutionary history, kinship relationships, and related gene functions. Homologous genes show different expression up-/down-regulations patterns. However, the alignment and phylogenetic analysis results showed an identity matrix and a distance matrix showing differences between up-regulated and down-regulated homologous genes. The differences between these genes are thought to be due to differences in the specific motifs of their constituent bases.