Genetic manipulation of aspartate aminotransferase levels in Brassica napus: Effects on nitrogen use efficiency.

摘要

Current farming practices include applications of nitrogenous fertilizers to increase plant growth. These fertilizers are applied in excess to compensate for losses due to volatilization, leaching, and denitrification which, contribute to numerous deleterious health and environmental effects. One solution to curb the use of excess fertilizer is to develop nitrogen efficient plants that maintain a high yield when grown at reduced nitrogenous fertilizer rates. I have focused on developing these nitrogen efficient plants by over-expressing an aspartate aminotransferase (AAT) gene in a Brassica napus background. Thirteen independent transgenic lines containing a single insertion event were identified and advanced to the T3 generation for characterization. One of these lines represents a putative nitrogen efficient genotype, accumulating higher shoot and root biomasses than control plants. The increases however, could not be replicated in a second experiment. Surprisingly, none of the lines showed a detectable increase in AAT activity despite evidence of transgene expression.