Development of Transgenic Wheat
with Improved
Salt & Drought Tolerance

Field crops are often prevented from achieving their full genetic potential by biotic or abiotic environmental stresses. Water stress (hyperosmotic) caused by drought and salinity is the most important abiotic factor limiting plant growth and crop productivity worldwide. Arable land acreage is limited in Egypt due to the lack of water needed for irrigation. The amount of High Dam water available is only sufficient for two million feddans of cultivated land along the north coast of Egypt. Therefore, the possibility of future irrigation with mixed fresh and sea water raises the need for developing wheat cultivars with increased salt and drought tolerance.

Collaboration between Ain Shams University and AGERI started years ago, when Dr. Bahieldin used microprojectile bombardment system at AGERI to transform immature embryos of Egyptian and American bread wheats with two genes for salt and drought tolerance (mtlD and HVA1). From this collaboration, six putative transgenic plants of both cultivars have been obtained. In addition, we have been successful in increasing regeneration and transformation efficiencies for both cultivars by shortening the selection period, bombarding young immature embryos, using low dicamba concentrations and allowing callus to recover for a week after bombardment.

We now propose to examine the effects of the two genes deployed thus far plus one additional gene for improving water-stress tolerance in wheat. The three genes to be utilized are: mtlD, HVA1 and a chimeric gene for fructan accumulation. Both ABA-inducible and the maize ubi promoters will be used to obtain optimal expression transgene levels. Genes will be cloned into E. coli expression vectors in order to obtain antibodies needed for subsequent tests of transgene expression in regenerated plants. Three selection criteria will be tested for callus-derived transformed cells, including herbicide (bialaphos) resistance expressed as a result of the selectable marker (bar), NaCl selection and PEG selection.

•  Transform Egyptian and American wheat cultivars with genes for salt and drought tolerance.

•  Conduct greenhouse and field performance trials of regenerated transgenic plants.

•  Improve selection, transformation and regeneration efficiencies for Egyptian and American wheat cultivars.

•  Incorporate transgenic plants with improved salt and drought tolerance into ongoing Egyptian and American breeding programs.

•  Enhance collaborative relationships that will improve modern genetic technology in Egyptian agricultural research.