Abstract
Different types of microRNA participate in the post-transcriptional regulation of target genes. The content of several hypoxia-dependent miRNAs in plant cells, including miR775, increases in the conditions of oxygen deficiency. Electrophoretic studies of total RNA samples from the leaves of flooded seedlings of maize (Zea mays L.) revealed the presence of two interfering complexes with miR775 at 12 h of hypoxic incubation. A nucleotide sequence analysis of a sample containing the interfering complex of miR775 with mRNA from maize leaves showed a high degree of homology with the ICL/PEPM_KPHMT lyase family domain. It corresponded to a fragment of fructose-1,6-bisphosphate aldolase mRNA. By real-time PCR, we established the dynamics of the content of transcripts of aldolase isoenzyme genes under hypoxia in maize leaves. A decrease in the transcriptional activity of the aldolase 1 gene (Aldo1) correlated with a high content of miR775 in maize leaf cells. The fraction of extracellular vesicles sedimented at 100,000× g, was enriched with miR775. The accumulation of aldolase 2 (Aldo2) mRNA transcripts under hypoxic conditions indicates its participation in maintaining glycolysis when Aldo1 expression is inhibited. We conclude that an increase in the total content of free miR775 and its participation in the suppression of the Aldo1 gene represents an important mechanism in developing the adaptive reaction of cellular metabolism in response to hypoxia.