Ozone and aging up-regulate type II metacaspase gene expression and global metacaspase activity in the leaves of field-grown maize (Zea mays L.) plants

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• 作者：Rafiq Ahmad^a ; Yasmine Zuily-Fodil^a ; Chantal Passaquet^a ; Olivier Bethenod^b ; Romain Roche^b ; Anne Repellin^a ; ^{repellin@u-pec.fr}
• 关键词：Tropospheric O3 ; Type II metacaspases ; Zea mays L. ; RT-qPCR ; Global metacaspase activities
• 刊名：Chemosphere
• 出版年：2012
• 期刊代码：15_00456535
• 类别：env
• 出版时间：May, 2012
• 卷：87
• 期：7
• 页码：789-795
• 文件大小：622 K

摘要

Maize plants (Zea mays L. cv. NK Perform) were exposed to O₃-enriched air, using a new field fumigation system. Transcriptional changes for three type II-metacaspase genes were studied in the leaves (ranks 10 and 12), using quantitative real-time PCR. Global metacaspase activity was measured using metacaspase-specific synthetic tripeptide Boc-GRR-AMC. Aging had little effect on mRNA accumulation whereas four to six-fold increases were observed for the most O₃-responsive type II metacaspase genes, in the older leaves 10. Global metacaspase activity increased by 257%and 333%in leaves 12 and 10, respectively, in response to the highest cumulated concentration. In non-fumigated plants, metacaspase activity progressively increased over the course of the experiment and always was higher in the older leaves 10. Together, these results suggest that metacaspase-mediated proteolysis is a crucial step in leaf responses to both O₃ and age-mediated senescence.