Ectopic overexpression of AtmiR398b gene in tobacco influences seed germination and seedling growth

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 stem-loop RT-PCR analysis confirmed the existence, and conserved nature of miR398 in t...

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Bibliographic Details
Published in:Plant cell, tissue and organ culture tissue and organ culture, 2010-07, Vol.102 (1), p.53-59
Main Authors: Feng, Xiao-Ming, Qiao, Yu, Mao, Ke, Hao, Yu-Jin
Format: Article
Language:English
Subjects:
Accumulation
Antioxidants
Arabidopsis
ascorbate peroxidase
Ascorbic acid
Biological and medical sciences
Biomedical and Life Sciences
Biotechnology
Catalase
Chlorophyll
Copper
drug crops
Fundamental and applied biological sciences. Psychology
Gene expression
gene expression regulation
Genes
Germination
Homeostasis
Hydrogen peroxide
L-Ascorbate peroxidase
Life Sciences
microRNA
miRNA
Nature conservation
Nicotiana tabacum
nutrient deficiencies
Original Paper
Peroxidase
peroxidases
Plant Genetics and Genomics
Plant growth
Plant Pathology
Plant Physiology
Plant Sciences
Polymerase chain reaction
Post-transcription
posttranscriptional regulation
reverse transcriptase polymerase chain reaction
RNA
Seed germination
seedling growth
Seedlings
Superoxide dismutase
Tobacco
transcription (genetics)
Transgenic plants
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Summary: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 stem-loop RT-PCR 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 down-regulated 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.
ISSN:0167-6857
1573-5044
DOI:10.1007/s11240-010-9704-x