TY  - JOUR
AU  - Ceron-Garcia, Abel 
AU  - Gonzalez-Aguilar, Gustavo Adolfo 
AU  - Vargas-Arispuro, Irasema 
AU  - Islas-Osuna, Maria Auxiliadora 
AU  - Martinez-Tellez, Miguel Angel 
PY  - 2010
TI  - Oligoglucans as Elicitors of an Enzymatic Antioxidant System in Zucchini Squash (Cucurbita pepo L.) Seedlings at Low Temperature
JF  - American Journal of Agricultural and Biological Sciences
VL  - 6
IS  - 1
DO  - 10.3844/ajabssp.2011.52.61
UR  - https://thescipub.com/abstract/ajabssp.2011.52.61
AB  - Abstract: Problem statement: Non-controlled low temperatures affect physiological and biochemical
processes leading to Reactive Oxygen Species (ROS) accumulation in plants, which normally are
stabilized by the antioxidant system. Superoxide Dismutase (SOD), Ascorbate Peroxidase (APX) and
Catalase (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-stressed
cotyledons of Cucurbita pepo L. Cold stress condition was settled in zucchini cotyledons using relative
Ion Leakage (IL) and H2O2 accumulation. Then, OG were obtained from Trichoderma harzianum cellwall
by enzymatic and chemical hydrolysis. These elicitors were purified by size-exclusion and anionexchange
chromatography and tested in cold-stressed cotyledons. Results: No significant changes on
H2O2 content and IL were observed between treated and control cold-stressed cotyledons, during the
first 7 days of storage at 5°C. Afterwards H2O2 values increased greatly after cold-stressed. Then, cold
stress conditions were established (7 d, 5°C). The APX and CAT activities remained stable, but not
SOD 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 activity
was only increased by an enzymatic OG mixture (EM). The APX activity level was increased in coldstressed
cotyledons 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 were
detected in SOD activity. The highest CAT activity levels were triggered using OG anion-exchange
chromatography 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 and
CAT activity in cold-stressed zucchini cotyledons mediated by T. harzianum cell-wall OG.