Oligoglucans as Elicitors of an Enzymatic Antioxidant System in Zucchini Squash (Cucurbita pepo L.) Seedlings at Low Temperature | Science Publications

American Journal of Agricultural and Biological Sciences

Gustavo A. Gonzalez-Aguilar¹  Irasema Vargas-Arispuro¹  Abel Ceron-Garcia¹  Miguel A. Martinez-Tellez¹  Maria A. Islas-Osuna¹ 

关键词: Antioxidant response;    cold stress;    fungal oligoglucans;    Reactive Oxygen Species (ROS);    Superoxide Dismutase (SOD);    Ascorbate Peroxidase (APX);    Catalase (CAT);    Oligoglucans (OG);    Cucurbita pepo L;   

DOI  :  10.3844/ajabssp.2011.52.61

学科分类：农业科学（综合）

来源: Science Publications

【 摘 要 】

Problem statement: Non-controlled low temperatures affect physiological and biochemicalprocesses leading to Reactive Oxygen Species (ROS) accumulation in plants, which normally arestabilized by the antioxidant system. Superoxide Dismutase (SOD), Ascorbate Peroxidase (APX) andCatalase (CAT) are the most important ROS-detoxification enzymes in stressed plants. Approach:The activity of these enzymes were examined in response to fungal Oligoglucans (OG) in cold-stressedcotyledons of Cucurbita pepo L. Cold stress condition was settled in zucchini cotyledons using relativeIon Leakage (IL) and H₂O₂ accumulation. Then, OG were obtained from Trichoderma harzianum cellwallby enzymatic and chemical hydrolysis. These elicitors were purified by size-exclusion and anionexchangechromatography and tested in cold-stressed cotyledons. Results: No significant changes onH₂O₂ content and IL were observed between treated and control cold-stressed cotyledons, during thefirst 7 days of storage at 5°C. Afterwards H₂O₂ values increased greatly after cold-stressed. Then, coldstress conditions were established (7 d, 5°C). The APX and CAT activities remained stable, but notSOD activity, which decreased about 42% in control cotyledons. When a chemical OG mixture (CM)was applied to cold-stressed cotyledons, APX and CAT activity levels increased. The SOD activitywas only increased by an enzymatic OG mixture (EM). The APX activity level was increased in coldstressedcotyledons using OG size-exclusion chromatography fractions from both CM and EM;however, changes in CAT activity were only possible using EM fractions and no changes weredetected in SOD activity. The highest CAT activity levels were triggered using OG anion-exchangechromatography sub-fractions from both CM and EM fractions (120 and 119 % of enzymatic activity,respectively). Conclusion: The oxidative stress can be counteracted by the triggering of APX andCAT activity in cold-stressed zucchini cotyledons mediated by T. harzianum cell-wall OG.

【 授权许可】

Unknown