Transgenic wheat plants expressing an oat arginine decarboxylase cDNA exhibit increases in polyamine content in vegetative tissue and seeds

Abstract

We generated and characterized a transgenic wheat (Triticum aestivum L.) population expressing constitutively an oat arginine decarboxylase (ADC) cDNA. Transgenic wheat plants expressing the transgene had a significant increase in ADC activity with no concomitant changes in ODC activity. We measured 2-fold increases in putrescine, spermidine and spermine content in leaves of transgenic plants compared to wild-type. These plants also exhibited significant increases in the three polyamines in seeds (7-fold putrescine, 2.5-fold spermidine and 1.8-fold spermine). This significant polyamine accumulation was heritable in subsequent generations. In order to characterize molecularly this population we cloned a partial TaADC cDNA. This sequence was used as a probe to ascertain the presence of two distinct ADC transcripts in wheat. Further DNA analyses confirmed the presence of at least two distinct ADC genes in the wheat genome. Our results demonstrate that polyamine levels can be altered in transgenic wheat plants resulting in phenotypically normal and fertile plants. This transgenic wheat population will serve as useful germplasm to embark on further in depth studies to ascertain the role of polyamines in abiotic stress responses.