Digital gene expression of water-stressed Phyllanthus urinaria (Dukung anak)

V. Maheswary, H.N. Khairun, S. Vasanthi and O. Nur Qistina

Abstract

In this study, we investigated the up- and down-regulation of genes involved in the secondary metabolite biosynthesis pathways in mature dukung anak (Phyllanthus urinaria) plants known to produce phytochemicals. Phytochemicals could contribute to human health by subjecting them to drought stress under net house conditions. Our raw data analyses using digital gene expression (DGE) technology showed that the number of sequence tags in the water-stressed plants was 1.9 folds more than in the control plants. Blast analysis showed that more than 90% of these sequences matched to the annotated sequences in the plantTA database with an up- or down-regulation of several genes in the main isoprenoid, shikimate, fatty acids, steroids and amino acids biosynthesis pathways in the water-stressed plants. Several enzymes were induced after water-stress but at a low frequency while some were either completely suppressed or showe no change in their expression. Gene Ontology (GO) analysis at level 2 revealed a significantly higher number of annotated sequences (E-value ≤10–6) in the water-stressed plants in each of the biological process, molecular function and cellular component categories, compared to the control plants. The results clearly indicated the beneficial effect of water-stress in increasing the production of several useful secondary metabolites in P. urinaria plants.

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