Stress Sensitivity Is Associated with Differential Accumulation of Reactive Oxygen and Nitrogen Species in Maize Genotypes with Contrasting Levels of Drought Tolerance.
Drought stress decreases crop growth, yield, and can further exacerbate pre-harvest aflatoxin contamination. Tolerance and adaptation to drought stress is an important trait of agricultural crops like maize. However, maize genotypes with contrasting drought tolerances have been shown to possess both common and genotype-specific adaptations to cope with drought stress. In this research, the physiological and metabolic response patterns in the leaves of maize seedlings subjected to drought stress were investigated using six maize genotypes including: A638, B73, Grace-E5, Lo964, Lo1016, and Va35. During drought treatments, drought-sensitive maize seedlings displayed more severe symptoms such as chlorosis and wilting, exhibited significant decreases in photosynthetic parameters, and accumulated significantly more reactive oxygen species (ROS) and reactive nitrogen species (RNS) than tolerant genotypes. Sensitive genotypes also showed rapid increases in enzyme activities involved in ROS and RNS metabolism. However, the measured antioxidant enzyme activities were higher in the tolerant genotypes than in the sensitive genotypes in which increased rapidly following drought stress. The results suggest that drought stress causes differential responses to oxidative and nitrosative stress in maize genotypes with tolerant genotypes with slower reaction and less ROS and RNS production than sensitive ones. These differential patterns may be utilized as potential biological markers for use in marker assisted breeding.
United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Crop Protection and Management Research Unit, Tifton, GA 31793, USA. yanglm@uga.edu.|Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA. yanglm@uga.edu.|School of Life Sciences, Huaiyin Normal University, Huaian 223300, China. yanglm@uga.edu.
Liming
L
Yang
Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA. jfount1@uga.edu.
Jake C
JC
Fountain
Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA. huixu@uga.edu.
Hui
H
Wang
United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Crop Genetics and Breeding Research Unit, Tifton, GA 31793, USA. xinzhi.ni@ars.usda.gov.
Xinzhi
X
Ni
Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA. pji@uga.edu.
Pingsheng
P
Ji
Department of Crop and Soil Sciences, University of Georgia, Tifton, GA 31793, USA. deweylee@uga.edu.
Robert D
RD
Lee
Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA. kemerait@uga.edu.
Robert C
RC
Kemerait
United States Department of Agriculture, Agricultural Research Service (USDA-ARS), U.S. Horticultural Research Laboratory, Fort Pierce, FL 34945, USA. brian.scully@ars.usda.gov.
Brian T
BT
Scully
United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Crop Protection and Management Research Unit, Tifton, GA 31793, USA. baozhu.guo@ars.usda.gov.
Baozhu
B
Guo
D055864:Droughts; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D036226:Seedlings / Q000378:metabolism* / Q000502:physiology*; D003313:Zea mays / Q000378:metabolism* / Q000502:physiology*
D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species
drought stress; maize seedlings; reactive nitrogen species; reactive oxygen species