miRNAs expression changes in maize seedlings in response to cadmium stress

Cadmium as a heavy metal which contaminate the environment and soil, negatively affects the growth and yield of plants. Plant response to cadmium stress is correlated with regulation of stress-related genes expression in plants. MicroRNAs (miRNAs) are a group of small non-coding RNAs (about ۲۴-۲۰ nucleotides) and known as negative regulators of gene expression in plants. According to previous studies, mir۱۶۸, mir۳۹۰, and mir۵۲۸ play an important role in regulating the expression of genes associated with heavy metal stresses. In this research, considering the economic and agricultural importance of maize, the effect of moderate cadmium contamination (۱۰۰ ppm CdCl۲) on expression of mir۱۶۸, mir۳۹۰, and mir۵۲۸ in ۳ days-old seedlings and roots of ۶- and ۱۲-days old plants was analyzed by qRT-PCR. In addition, plant growth parameters and cadmium absorption was considered. The results showed that mir۱۶۸ is down-regulated and mir۳۹۰ and mir۵۲۸ are up-regulated in ۳-days old seedlings under cadmium contamination, while cadmium absorption did not start in these seedlings under cadmium stress. In ۶-days old plants, the cadmium absorption was observed and the expression of these miRNAs significantly decreased. The down regulation of these miRNAs is continued with increase of cadmium amount in roots of ۱۲-days old plants. In general, the comparison of the expression pattern of these miRNAs revealed the importance role of these miRNAs in roots of maize plant during cadmium stress. Further comprehensive research on expression analysis of the target genes of these miRNAs and the other cadmium-related genes highlight novel molecular mechanisms of cadmium stress tolerance in maize plant.

کلیدواژه ها:

mir۱۶۸ ، mir۳۹۰ ، mir۵۲۸ ، cadmium stress ، Zea mays L.