Authors: XiaoMing Feng Yu Qiao Ke Mao YuJin Hao
Publish Date: 2010/02/22
Volume: 102, Issue: 1, Pages: 53-59
Abstract
MicroRNAs play crucial roles in plant development and growth nutrient allocation and stress responses by posttranscriptionally regulating their target genes In the present investigation RNA blotting studies and stemloop RTPCR analysis confirmed the existence and conserved nature of miR398 in tobacco The positive accumulation of miR398 in response to copper deficiency provided additional evidence for the involvement of miR398 in plant responses to copper homeostasis The functional characterization of miR398 in tobacco was performed by choosing two transgenic tobacco lines containing Arabidopsis AtmiR398b gene with miR398 accumulation at different levels The result showed that miR398 oversupply derived from AtmiR398 overexpression in tobacco downregulated the activities of antioxidant enzymes such as superoxide dismutase SOD catalase CAT peroxide dismutase POD and ascorbate peroxidase APX possibly due to the posttranscriptional regulation of miR398 to its target genes As a result transgenic tobacco lines produced more O2 − and H2O2 but less chlorophyll than the control In addition miR398 oversupply inhibited seed germination and seedling growth especially under copper and salt stresses The present results confirm that miR398 exists and functions in tobacco in a conserved way similar to Arabidopsis
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