Water scarcity has been known to decrease the photosynthesis rate leading to reduce yields of banana (Musa spp) production. Transcriptomic analysis was accomplished to identify photosynthetic genes and determine its expression profiles as the impact of water stress treatment. Banana plantlets were in vitro cultured on Murashige and Skoog agar medium with and without the addition 10% polyethylene glycol, and noted as BP10 and BK. Chlorophyll contents were determined spectrophotometrically from shoots of plantlets. Two cDNA libraries generated from BK and BP10 plantlets were used as the reference of transcriptome data. Gene ontology enrichment was achieved using the database of DAVID and visualized with the pathway prediction of KEGG. Morphological observation indicated that water deficiency caused chlorosis and reduced the chlorophyll contents in shoots of banana plantlets. The GO enrichment identified 52 photosynthesis-related genes that affected by water stress. The KEGG visualized the 52 photosynthetic genes pathways and their allocations in four GO terms. There were 4 genes identified in chlorophyll biosynthesis, 12 genes in the Calvin cycle, 15 genes in the photosystem-electron transfer chain, and 21 genes in the light harvesting complex. Relative gene expression analysis using DESeq determined that 45 genes were down-regulated, and 7 genes were up-regulated. Four down-regulated genes were responsible for chlorophyll biosynthesis and seemed to cause the decrease of chlorophyll contents in leaf tissues of plantlets. The MaPNDO, MaPSAL, and MaFEDA genes were selected from annotated DEGs and validated using the quantitative real-time PCR.

Keywords: Musa acuminata Colla, Photosynthesis, Transcriptome analysis, Water deficiency