Over-expression of samdc gene for drought tolerance in Egyptian cotton using genetic engineering
2011
Ibrahim, E.M.H.
Polyamine (PAs) is polybasic aliphatic amine that plays a role in enhancing the environmental stresses tolerance. S-adenosyl methionine decarboxylase (SAMDC) gene produces a key regulatory enzyme in polyamine biosynthetic pathway and therefore in turn on is responsible for carrying plants to drought tolerance. In this study, SAMDC gene cDNA was isolated from yeast; Saccharomyces cerevisiae S288c strain by RT-PCR approach and engineered in the embryonic axes meristem of Egyptian cotton cultivars; Giza 88 and Giza 90 by means of particle bombardment. Preliminary tests were conducted on the resulting plants using basta (100 mg /L) and at the molecular level by PCR. The seeds of T1 plants were sown in greenhouse and tested again using basta (100 mg/L). The resulting plants which revealed resistances to basta with the control plants were subjected to drought regime using 17% concentration of PEG 6000. The results indicated that this percentage is considered the sub-lethal concentration showing drought stress symptoms. T1 putatively transgenic plants subjected to stress were tested using RT- PCR and Southern blot analyses; it indicated that SAMDC gene was integrated inside the plant genome of T1 stress putatively transgenic plants. HPLC analysis of T1 plants showed an increased level of spermine (compound of PAs) to 17% in each of the two transgenic plants compared to non-transgenic ones and this increment in gene expression reflected an increased tolerance of plants to drought stress.
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