This study aimed to find water stress markers in Arabidopsis thaliana. I cultivated plants with drought and salt stresses in a growth room. To compare responses of each stress, I measured phenotypic traits first; then, I analyzed the metabolome pattern with gas chromatography-mass spectrometry (GC-MS). In morphology measurement, I considered three traits; flowering time, biomass, and plant color. Each morphology was analyzed using one-way ANOVA. Flowering time and biomass showed a tendency to reduction than the non-stress group. The color of plants divided by either drought or salt. Drought stress induces dark color, and salt stress presents a bright yellow color in Arabidopsis thaliana. Color changed patterns were elucidated with plant pigments using linear regression. In drought conditions, plant color was influenced by the accumulation of anthocyanin than reduction of chlorophyll a content and anthocyanin was more accumulated with strong stress states. However, in salt stress, plant color was influenced reduction of chlorophyll a than accumulation of anthocyanin. Unlike drought stress, chlorophyll a was only reduced significantly in harsh salt stress. It is hard to explain about stress level quantitatively. Thus, morphology measurement can be shown which stress is occurred to plants habitats, but it cannot explain stress level quantitatively. In metabolome analysis, I did a principal component analysis (PCA) for comparing metabolome pattern with each stress condition and finding stress markers. PCA result represented different metabolome patterns with stress strength in the same stress condition. It revealed different patterns by sort of stress as well. Then, I selected stress markers candidates using the loading values of each metabolite. Then, maltose and L-serine were selected for each water stress marker; drought stress marker is maltose and salt stress marker is L-serine. These specific markers play an important role as good indicators for each water stress in my model. As a result, specific metabolite markers can evaluate stress strength as well as identify each water stress. In conclusion, this study provides specific stress markers for water stress in Arabidopsis thaliana.
