CURRENT RESEARCH

Adverse environmental conditions such as drought and extreme temperatures greatly impair crop productivity.  Since plants cannot move to avoid stressful conditions, they must employ alternative ways to withstand stress in order to survive.  Plant cells are able to sense and transmit these environmental signals into cellular machinery to activate certain molecular and physiological changes.  Some of these changes are adaptive and can make the plants more resistant to stress.  Our laboratory is interested in understanding the mechanisms for stress signal transduction in the model plant Arabidopsis.  Knowledge gained in the study will help us to devise better strategies for breeding crop plants with increased tolerance to stress.

Drought Tolerance  Drought occurs virtually in all agricultural areas.  Unfortunately, very little is known about how plants deal with drought stress: Genetic analysis of plant drought stress responses is impeded by difficulties in manipulating drought in a quantitative way and by our limited awareness of plant phenotypes specifically conferred by drought stress.  Recently, we obtained Arabidopsis mutants that show altered drought resistance.  These mutants will serve as useful tools for further study on plant drought stress signal transduction and drought tolerance.

Stress Hormone: Biosynthesis and Signaling  The plant hormone, abscisic acid (ABA), regulates a wide range of cellular processes including responses to environmental stress.  ABA levels in plant cells remain low under non-stressful conditions but can increase dramatically during seed maturation and in response to stress, suggesting that ABA biosynthesis is highly regulated.  Nonetheless, very little is known about the mechanism of this regulation.  The recent identification of genes that encode ABA biosynthesis enzymes offers an opportunity to understand how ABA biosynthesis is modulated.  Our study attempts to reveal stress-signaling pathways that culminate in de novo ABA biosynthesis.

Plant Nutrient Efficiency and Tolerance to Soil Acidity  Low soil fertility is a major constraint in crop production for many developing countries.  One of the major nutrients, phosphorus, is of particularly low availability as a result of high fixation in tropical and subtropical acidic soils.  Our laboratory uses molecular genetic approaches to uncover processes in roots that control phosphorus efficiency.  Since phosphorus efficiency and tolerance to high acidity (aluminum toxicity) are closely linked traits, this study will also shed light on mechanisms of plant tolerance to soil acidity.