Molecular and cellular adaptations of maize to flooding stress.

Anaerobic treatment dramatically alters the patterns of gene expression in maize (Zea mays L.) seedlings. During anaerobiosis there is an immediate repression of pre-existing protein synthesis, with the concurrent initiation of a selective synthesis of approx. 20 proteins. Among these anaerobic proteins are enzymes involved in glycolysis and related processes. However, inducible genes that have different functions were also found; these may function in other, perhaps more long-term, processes of adaptations to flooding, such as aerenchyma formation and root-tip death. In this article we review our recent work on maize responses to flooding stress, which has addressed two questions: how are these gene expression changes initiated and how do they lead to adaptation to flooding stress? Our results indicate that an early rise in cytosolic Ca(2+), as well as a quick establishment of ionic homeostasis, may be essential for the induction of adaptive changes at the cellular as well as organismal level.