Effects of temperature stress on the accumulation of ascorbic acid and folates in sweet corn (Zea mays L.) seedlings.

Extreme temperatures are among the primary abiotic stresses which affect plant growth and development. Ascorbic acid (AsA) is an efficient antioxidant for scavenging relative oxygen species accumulated under stress. Folates play a significant role in DNA synthesis and protect plants against oxidative stress. Sweet corn (Zea mays L.), a crop grown worldwide, is sensitive to extreme temperature at seedling stage which may cause yield loss. This study was conducted to explore the biosynthetic regulative mechanism of AsA and folates in sweet corn seedlings under temperature stress.

The AsA and folates compositions and relative gene expressions of sweet corn seedlings grew under different temperature stresses (10°C, 25°C and 40°C) were evaluated. The imposition of temperature stress altered the AsA content mainly by modulating the expression of _Zm DHAR, whose encoded enzyme dehydroascorbic reductase (DHAR) is essential in the AsA recycle pathway. Low temperature stress raised the expression of relative gene, leading to folate accumulation. High temperature stress modulated the folates content by influencing the expression of correspondence gene of aminodeoxychorismate synthase, _Zm ADCS, as well as downstream genes which connected with DNA methylation.

These results provided a theoretical basis at genetic level for understanding the stress responses mechanism in sweet corn seedlings and a guidance for sweet corn cultivation. This article is protected by copyright. All rights reserved.