ANAEROBIC GENE-EXPRESSION AND FLOODING TOLERANCE IN MAIZE

Anaerobic treatment dramatically alters the pattern of gene expression in maize (Zea mays L.) seedlings, During anaerobiosis there is an imm ediate repression of pre-existing protein synthesis and the simultaneo us selective synthesis of four polypeptides with a molecular weight of similar to 33 kDa (the transition polypeptides), After 90 min, this i s followed by specific transcription and mRNA accumulation as well as the selective synthesis of approximately 20 anaerobically-induced prot eins, Among these anaerobic proteins (ANPs) are enzymes involved in gl ycolysis and related processes, such as alcohol dehydrogenase (ADH) al dolase, enolase, glucose-phosphate isomerase, glyceraldehyde-3-phospha te dehydrogenase, pyruvate decarboxylase, and sucrose synthase, Howeve r, two genes, inducible by oxygen deprivation, have been found that ha ve different functions, One that has homology to xyloglucan endotransg lycosylase may be involved in aerenchyma formation during flooding, Th e anaerobic response is most likely a plant's natural reaction to floo ding, A similar condition has been observed in every plant species ana lysed to date. The anaerobic response and flooding tolerance in maize has been analysed using a combination of molecular, biochemical and ge netic approaches, The studies include the characterization of anaerobi cally inducible genes, the identification of genes involved in floodin g tolerance, and analysis of the signal transduction events that are i nvolved in the perception of oxygen deprivation and lead to the anaero bic response.