Using Different Rice Cultivars to Study the Relationship Between Sugars and Rice Cold Stress Tolerance
Date Issued
2010
Date
2010
Author(s)
Chien, Wei-Fu
Abstract
Carbohydrates play important roles in plant stress physiology, such as nutrient supplementation, osmotic adjustment, maintain of membranes stability and singaling molecule. Carbohydrates can be present in cytosol, vacuole and cell wall. Depend on the composition and structures, carbohydrates can be grouped into monosaccharide, disaccharide, oligosaccharide and polysaccharide. Many studies had shown the correlation of carbohydrates change under various abiotic stress in plant. In this study, we are interesting in understanding the complexity of intracellular water-soluble polysaccharide (PS) changes in rice under cold stress. High-performance anion-exchange chromatography was used to analyze the effect of cold stress on polysaccharide pattern changes in TNG67, including total PS production, the molecular weight distribution and sugar composition. The accumulation of PS fraction (0.72~0.74 kDa) was increased from 6% to 13% in TNG67 rice shoot under cold treatment. The compositional analysis of PS showed that glucose and fructose level increased from 20 and 36 μmol/g PS to 32 and 54 μmol/g PS during cold treatment, however; arabinose, fucose, sorbitol and myo-inositol level decreased from 102, 9, 2 and 0.6 μmol/g PS to 50, 5, 0.94 and 0.43 μmol/g PS. In addition, we analyzed gene expression of TNG67 under cold treatment with microarray, especially for those carbohydrate metabolism related gene. Finally, we tried to integrate sugar expression profiling data and microarray gene analysis to reveal the correlation of gene and sugar change under cold treatment in rice. The correlation between carbohydrate metabolite and biosynthesis related genes change was high as 80~90%. We also confirmed the gene expression by real-time PCR. To further revel in the role of polysaccharide in rice cold tolerance, we used different rice cultivars TCN1 (cold sensitive) and TNG67 (cold tolerant) as experimental materials and monitored the carbohydrate profiling change in shoot and root of TCN1 and TNG67 under cold and rewarm condition. The content of various sugars in shoot of TNG67 was higher than TCN1 under rewarm condition, and the those sugar contents was also higher TNG67 root under cold. This result suggested that the glucose and fructose may play important role in rice cold stress tolerance.The dynamic change of arabinose is opposite in different cultivars and tissue.The content of galactose was increased in TNG67 under cold treatment.
Meanwhile, to investigate the role of PS change under cold stress, we compared the PS expression profiling between AtICE overexpressed transgenic rice and TNG67. The overexpression of AtICE1 with 35S promoter in rice had been shown to enhance cold stress tolerance (Hsin-Hsiu Fang, 2008).Here, we further confirmed the cold stress tolerance of AtICE1 overexpressed transgenic rice by various physiological assays. The content of MDA and H2O2 in transgenic rice was lower than WT. The superoxide dismutase (SOD), ascobate peroxidase (APX) and catalase (CAT) activity of transgenic rice was higher than those of WT. The level of ascobate/dehydroascobate (ASC/DHA) was higher in transgenic rice. Taken together, the above results indicated antioxidant activity was higher in transgenic rice. The amino nitrogen and protein content of transgenic rice was higher than WT under normal and cold condition. By analysis of PS expression profiling HPAEC showed that the glucose and fructose content of transgenic rice was higher than WT either at normal or cold condition.
In this study, we established the correlation between intracellular PS and rice under cold treatment. We also integrated sugar contents and microarray gene expression to demonstrate that levels of carbohydrate may regulate at transcription level. We also characterized the physiologic response, especially antioxidant activity in AtICE1 overexpressed transgenic rice and showed that carbohydrates, particularly glucose and fructose increased in AtICE1-OX compared to wild type.
Subjects
polysaccharide
rice
cold stress
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-R97621103-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):d77bbe2f455bb098def6e8db32707d4e