Sequential expression of two 1-aminocyclopropane-1-carboxylate synthase genes in response to biotic and abiotic stresses in potato (Solanum tuberosum L.) leaves.

Plants produce ethylene in response to many biotic and abiotic stresses. In response to ozone the foliage of potato plants sequentially expressed two ACC synthase genes (ST-ACS4, ST-ACS5). The same expression pattern of the two genes also occurred in response to Cu2+ and infection with Alternaria solani. ST-ACS5 expression increases very rapidly reaching a maximum earlier than ST-ACS4 transcripts, after which ST-ACS5 expression declines. ST-ACS4 expression increases at a slower rate and reaches its maximum after ST-ACS5. The sequential nature of expression argues that the two genes have different signal transduction and gene regulatory mechanisms.