Changes in sucrose metabolic enzymes to water stress in contrasting rice genotypes

Photosynthesis is the key process that controls metabolic movements in plants. Water stress reduces the rate of photosynthesis, leading to energy depletion and yield loss. Sucrose is the fundamental product of photosynthesis in plants, which acts as an important energy substrate and regulator of plant growth and developmental signals. In this study, two rice varieties, drought tolerant PTB7 (Parambuvattan) and drought susceptible PTB23 (Cheriya Aryan) were subjected to water deficit stress treatments to understand the changes in various physiological, biochemical mechanisms and sucrose metabolizing enzymes. Under water stress conditions, root biomass increased as compared to shoot biomass, which led to an increase in the root to shoot (R/S) ratio. Water stress enhanced the sucrose content in both leaves and roots of the rice plant, which may be due to the increased sucrose metabolism and transport under water stress conditions. Since then, there has been a notable increase in the activity of enzymes (α-amylase and β-amylase) and expression of genes such as sucrose transporter (SUC2) and sucrose synthase (OsSuSy) genes. In conclusion, the results showed that changes in sucrose distribution, metabolism, and transport in plants under water stress conditions contribute to tolerance in rice to water stress conditions.