Research

• Why can some plants tolerate highly saline soils, or survive severe drought conditions, or grow at low temperature?
• Asking the question differently - why can most plants NOT survive when exposed to severe abiotic stresses?

• So, what is missing in sensitive species? Is it that our understanding of gene functions is lacking, or that our appreciation of interconnected networks of genes is rudimentary - or are there some magical genes that are restricted to a few stress-tolerant species?

Our second rationale and justification of the work is the recognition that the major abiotic stresses - drought, termperature (low or high and freezing), and high salinity - cause a significant reduction in yield in most crop species. The effect of these stresses is economic hardship for farmers and it may be life-threatening for regions depending on subsistence farming. Some examples may highlight this problem. One example is rice production. Approximately half the rice consumed is obtained in dry-land, rain-fed cultivation. Drought can be devastating. Another example, more complex, is salinization. Some 15% of the worlds cultivated areas are irrigated and produce about one third of all products. Because long-term irrigation inevitably leads to increases in salinity (unless the excessions can be removed by large amounts of water) crop yields decline. Also, low or freezing temperature during germination or seedling establishment can cause problems later - slower or reduced vegetative growth can translate into lower seed or fruit production. Cumulatively, abiotic stresses are responsible for most of the discrepancy that exists between maximal and actual yield. Our focus has been on salt stress - to understand this stress, discern its osmotic and ionic stress components and to understand how (some) plants cope with this stress.

• Does an understanding of abiotic stress defense mechanisms translate into growing corn in the sea, or rice and soybeans in the Kalahari Desert?

Click to view individual projects in the lab.

Detail of a microarray slide containing 2000 ESTs (cDNAs) from a cDNA library of drought-stressed barley roots. Each DNA element was printed four times. The hybridization compared control vs. drought-stressed transcripts. The false color representation indicates in red and white if a transcript is upregulated under drought conditions Öztürk et al. (2002) Plant Mol Biol, in press.

• Gene Expression Profiles during the Initial Phase of Salt Stress in Rice
• Transcript Expression in Saccharomyces cerevisiae at High Salinity
• Expression and Stress-Dependent Induction of Potassium Channel Transcripts in the Common Ice Plant
• Na+/myo-inositol symporters and Na+/H+-antiport in Mesembryanthemum crystallinum
• Expression of the PIP aquaporin promoter-MipA from the common ice plant in tobacco.
• Disturbance in the allocation of carbohydrates to regenerative organs in transgenic Nicotiana tabacum L.
• Expression of Water Channel Proteins in Mesembryanthemum crystallinum
• Genomic approaches to plant stress tolerance
• Isolation, Characterization, and Functional Expression of cDNAsEncoding NADH-dependent Methylenetetrahydrofolate Reductase from HigherPlants
• Aquaporin localization – how valid are the TIP and PIP labels?
• Tissue- and environmental response-specific expression of 10 PP2C transcripts in Mesembryanthemum crystallinum.
• Plant stress adaptations – making metabolism move
• Salt stress in Mesembryanthemum crystallinum L. cell suspensionsactivates adaptive mechanisms similar to those observed in the wholeplant.
• Myo-Inositol-Dependent Sodium Uptake in Ice Plant
• Sorbitol-6-Phosphate Dehydrogenase Expression in Transgenic Tobacco
• Regulation of Cell-Specific Inositol Metabolism and Transport in Plant Salinity Tolerance