The seed biochemical signature as a potent marker for water logging tolerance in maize

Abstract

Plant breeders are in the need for convenient, reproducible, reliable and rapid screening methods to be used as a proxy for water logging tolerance for a large number of genotypes. Addressing this need, the present study was carried in order to identify potential biochemical markers in the seeds of 10 contrasting maize (Zea mays L.) genotypes differing in their tolerance against water logging. Results clearly indicate that tolerant genotypes inherently exhibit better antioxidant system as evident by higher activities of catalase and glutathione reductase than the susceptible genotypes hence minimizes resulting oxidative stress. Significantly higher activities of anaerobic metabolism enzymes viz. alcohol dehydrogenase, aldehyde dehydrogenase and pyruvate decarboxylase in tolerant maize genotypes signifies efficient system for the recycling of NADH for the continuation of glycolysis and simultaneous detoxification of acetaldehyde thus provides prolonged survival of tolerant plants under water logging. Higher Sucrose synthase (SuSy) activity in tolerant genotypes over the susceptible genotypes indicates uninterrupted supply of reducing sugars for glycolytic activity. The content of total and reducing sugars content was found 27% higher in tolerant genotypes, which is in agreement with the SuSy activity. Soluble sugars analysis through reverse phase HPLC revealed higher relative concentration of fructose and glucose in tolerant maize genotypes than susceptible genotypes. Tolerant genotypes also exhibited significantly lower phytic acid and higher proline content. Hence the observed biochemical diversity could be useful for screening and development of water logging stress-tolerant genotypes of maize.