Molecular and Physiological Parameters Associated to Drought Tolerance in Tomato Plants

Drought stress is one of the main causes that limit plant metabolism and growth, causing a reduction in crop yields. Numerous biochemical reactions have been described to be sensitive to drought. While it is difficult to estimate the magnitude of the loss in production due to drought stress, it is considered that water deficiency is the main abiotic stress in agriculture, which can affect up to 50% of the world production. This study analyses the physiological and molecular response of six old tomato varieties to moderate and strong drought stress.

Our results indicated that there exists a positive correlation a physiological level between drought tolerance and leaf water relative content, relative growth rate and stomatal conductance; on the other hand, at a molecular level the plant drought tolerance is correlated with an increase in metabolites of phenyl propanoid pathway, up-regulation in genes that encode to proteins involved in proline and ABA biosynthesis, and an increase in activity of antioxidant enzymes, indicating the importance of ROS metabolism in drought tolerance in tomato genotypes.