XVI International Botanical Congess

Adaptive responses to various environmental stresses result from the induction of overlapping sets of genes, with abscisic acid (ABA) playing a key role. Consequently, many stress-related genes respond to multiple signals reflecting both functional and regulatory redundancy. The Arabidopsis genes kin1 and kin2 exemplify these principles. Dehydration, osmoticum and ABA treatment increase expression from the kin1,2 promoters. Low temperature increases transcription from kin1,2 promoters but translation is reduced. In addition, kin1,2 expression is developmentally regulated. ABA 8' hydroxylase reduces ABA levels and therefore modulates plastic responses. Expression of the corresponding gene is also regulated by multiple signals including ABA and osmoticum.