Pre-breeding: the role of antioxidant enzymes on maize in salt stress tolerance

Abstract

Maize is a crop that is moderately sensitive to salt stress. Salinization of soil is a severe threat to maize production worldwide. Understanding the response and tolerance mechanism of maize to salt stress may be conducive to formulate strategies to improve maize performance under saline environments. In this study, salt-tolerant, salt-sensitive and moderate salt-tolerant maize plants were investigated, respectively, under salt stress conditions in three aspects: growth status, enzyme activity and gene expression level. After 30 days of planting and salt stress treatment, the plant height of USTB-297 (salt-tolerant maize) was 49.40% higher than that of USTB-265 (salt-sensitive maize) and 25.10% higher than that of USTB-109 (moderate salt-tolerant maize). Analysis of antioxidant enzymes superoxide dismutase (EC1.15.1.1), ascorbate peroxidase (EC1.11.1.11) and catalase (EC1.11.1.6) revealed that there are distinctions between these different breeds. Salt-tolerant breed with a higher plant height also had higher antioxidant enzyme activity and related genes expression compared to salt-sensitive or moderate salt-tolerant breed. The detection of gene expression in superoxide dismutase, catalase and ascorbate peroxidase using real-time PCR and the data of enzyme activity indicate that we can build a method of breeding for maize.