EXPRESSION PROFILE OF PHOTOSYNTHETIC GENES IN BANANA (MUSA ACUMINATA COLLA) PLANTLETS IN RESPONSE TO DROUGHT STRESS BASED ON TRANSCRIPTOME ANALYSES

• Main Author: Sulaiman, Syahril
• Format: Final Project
• Language: Indonesia
• Subjects: Ilmu hayati ; Biologi
• Online Access: https://digilib.itb.ac.id/gdl/view/79285
• Institution: Institut Teknologi Bandung

Drought is one of the main abiotic stresses in banana cultivation, which can reduce its production yields. However, the physiology and molecular mechanisms of banana plants to respond dry environments are not completely understood. Previous experiments generated a transcriptome dataset from four cDNA libraries of banana plantlets (Musa acuminata Colla) cv ‘Pisang Barangan Merah’ (PBM) which were exposed to a drought stress condition with the addition of PEG (polyethyleneglycol-6000) and sequenced using Illumina MiSeqTM 2000. Three different PEG concentration levels used in previous experiments were 2.5% (BP2), 7.5% (BP7), 10% (BP10), and those were equivalent to the osmotic potential (OP) at -0.19; -0.93; and -1.48 bars. Banana plantlets grown and regenerated on media without PEG were used as the control treatment (BK). The transcriptome dataset of BK; BP2; BP7 and BP10 from those previous experiments were used in this study to reveal the changes of expression profile of photosythetic genes in banana plantlets in respone to drought stress. In this study, further transcriptome analyses were conducted to identify photosynthetic genes, determine the relative expression levels of genes and evaluate the protein interaction patterns, using the bioinformatics softwares such as DAVID v6.7 (Database for Annotation, Visualization and Integrated Discovery), AgriGO V.2 (Agriculture Gene Ontology), KEGG (Kyoto Encyclopedia of Genes and Genomes), DESeq and STRING v.11 (SearchTool for the Retrieval of Interacting Genes) softwares. Analyses results showed a total of 52 photosynthesis related genes were identified based on GO enrichment analysis using DAVID software. Mapping these genes into the KEGG pathway indicated that only 48 of 52 genes had a role in banana photosynthesis process. The 48 genes consisted of 15 genes of light harvesting subprocess, 21 genes of photosystem-electron transfer subprocess, 9 genes of Calvin cycle, and 3 genes of chlorophyll biosynthesis. A total of 43 genes downregulated, 4 genes upregulated, and 1 gene down and upregulated at different drought levels. Compare to others, the pigment defective 345 (PDE345), fructose 1,6-bisphosphate aldolase 8 (FBA8), fructose 1,6-bisphosphate aldolase (FBA6), glyceraldehyde-3-phosphate dehydrogenase C2 (GAPC2) and glyceraldehyde-3-phosphate dehydrogenase of plastid 1 (GAPCP1) had the highest relative expression levels and were thought to have a play role in the mechanism of tolerance of banana plants to drought stress whereas the light harvesting complex b 4 subunit 1 (LHCB4.1), transketolase 2 (TKL2), protochlorophyllide oxidoreductase B (PORB), dan photosystem I subunit G (PSAG) genes had the lowest relative expression level. The proteins encoded by photosynthetic genes formed three clusters that are closely related to their photosynthetic subprocess. The LHCB4.1, PSAG, and TKL2 proteins have the most complex interactions compared to other proteins.