Regular mechanical stimuli alter physiological and biochemical responses in Oryza sativa L.

Thigmomorphogenetic adaptations can be used to improvise agricultural practices. Response to mechanical stimuli is extensively studied in dicot plants, with very few studies reported in monocot plants. This study was aimed to test the effect of mechanical stimuli on morphology, physiology and gene expression of Oryza sativa TN1 cultivar. Mechanical stimuli in the form of gentle touch were given to rice seedling. Fifteen days of touch, suppressed rice plant growth and triggered early senescence in older leaves. This is associated with immediate rise in ROS and chlorophyll degradation. Quantitative PCR analysis indicates that the expression of JA responsive genes, OsLOX2 and OsJAZ8 were 2-fold upregulated. Upon touch stimuli in rice seedling, the regulator of rice senescence, OsWRKY42 was found to be increased by 1.7-fold. Our study indicates that regular touch has significant impact on rice plant and it involves JA stress hormone.