Study of microRNAs involved in wounding response n sweet potato
Date Issued
2008
Date
2008
Author(s)
Lin, Jeng-Shane
Abstract
MicroRNAs (miRNAs) contain approximate 22 nucleotides that post-transcriptionally regulate gene expression by directing mRNA cleavage or translational inhibition. Currently, more than one hundred miRNAs that play multiple roles in growth, development, and stress responses of plants have been identified in Arabidopsis thaliana. Here, I investigated the expression patterns of miR159, miR407, and miRNA828 upon wounding in sweet potato. The expression of miR407 was undetectable in leaves and stems. However, miR159 was expressed in stems and, at low levels, in leaves, whereas miR828 was expressed in leaves and undetectable in stems. Furthermore, the expression of miR828 was decreased upon wounding in sweet potato. Additionally, several defensive responding compounds, including hydrogen peroxide (H2O2), nitric oxide (NO), methyl jasmonate (MeJA), abscisic acid (ABA), and ethylene also suppressed miR828 expression. However, carbon monoxide (CO) suppressed repression of miR828 by wounding. Interactions among these defensive responding compounds for the regulation of miR828 were also studied. Results suggested that wounding stimulates the biosynthesis of MeJA and NO. Then, MeJA activates NO synthase to generate NO. Finally, NO inspires the activity of NADPH oxidase to generate H2O2, which suppress miR828 expression. In addition to miR828, three potential miR828 targeted genes, receptor protein kinase (RPK), TLD, and MYB were isolated and were up-regulated by wounding. In addition, RPK, TLD, and MYB were regulated by NO and H2O2 when miR828 was repressed. These results imply that wounding represses the expression of miR828, and consequently regulates the expression of RPK, TLD, and MYB genes to protect plants from damage.
Subjects
miR828
sweet potato
target gene
wounding
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