Biochemical responses of rice roots to cold stress

Ching Hsin Hsu,Yi Ting Hsu

doi:10.1186/s40529-019-0262-1

Abstract

BackgroundCold stress is the main factor that reduces rice yield in subtropical areas, especially at the seedling stage. Most of the current studies on cold stress focus the responses of rice shoots to cold stress. Limited studies are available on that of rice roots to cold stress. This study aimed to illustrate the biochemical responses of rice root under cold treatment, and subject to the establishment of cold stress-related biochemical traits for rice breeding or cropping-adjustment.ResultsOur results showed that the growth of rice seedling diminished under cold stress with difference extents among eight rice cultivars of most productive in Taiwan. Under cold treatments, the tested cultivars with higher growth rate had a higher level of hydrogen peroxide (H2O2) in the shoots but had a lower level in the roots. In contrast, the tested cultivates with low growth rate had higher levels of H2O2 in the roots but a lower level in the shoots. Meanwhile, higher MDA contents and higher cell-damage related electrolyte leakage were also found in the roots not in the shoots, suggesting that cold stress might induce oxidative stress in the roots, not in the shoots. Furthermore, the activity analysis of four antioxidant enzymes, namely superoxide dismutase (SOD), catalase (CAT), ascorbic peroxidase (APX), and glutathione reductase (GR), revealed that cold stress could increase SOD and CAT activities in the roots.ConclusionsIn summary, low H2O2 and low MDA contents along with lower SOD and CAT activities in rice root could be the biochemical traits of cold responses in rice seedlings. The results are hoping to have a contribution to the rice breeding or cropping-adjustment on cold tolerance.

Highlights

Cold stress is the main factor that reduces rice yield in subtropical areas, especially at the seedling stage
Low temperatures may cause the accumulation of reactive oxygen species (ROS), such as superoxide anion, singlet oxygen, and hydrogen peroxide (H2O2), which leads to lipid peroxidation, electrolyte leakage, and membrane damage (Kuk et al 2003; Hung et al 2008; Bhattacharjee 2013)
We found that Cd toxicity in rice leaves is due to H 2O2 accumulation (Hsu and Kao 2007) and further reported that H 2O2 accumulation is responsible for Cd-inhibited root growth of rice seedlings (Cho et al 2012), where Cd could inhibit the activity of catalase (CAT), which is supposed to break down H2O2 into water and oxygen in rice roots

Summary

Introduction

Cold stress is the main factor that reduces rice yield in subtropical areas, especially at the seedling stage. The incidence of low temperature is one factor responsible for the declining yield, especially at the seedling stage (Aghaee et al 2011; Bhattacharjee 2013; Dashtmian et al 2014). This cost of cold damage is approximately 75% of all disaster loss in Taiwan (Additional file 1: Figure S1). Cold temperatures of 0–15 °C can reduce the crop survival rate, inhibit photosynthesis, retard growth, and block the synthesis of proteins, lipids, and carbohydrates (Setter and Greenway 1988; Aghaee et al 2011; Liu et al 2013). Low temperatures may cause the accumulation of reactive oxygen species (ROS), such as superoxide anion, singlet oxygen, and hydrogen peroxide (H2O2), which leads to lipid peroxidation, electrolyte leakage, and membrane damage (Kuk et al 2003; Hung et al 2008; Bhattacharjee 2013)

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