Identification of microRNAs involved in chilling response of maize by high-throughput sequencing

Abstract

Chilling stress impedes growth, development, and productivity of maize (Zea mays L.). MicroRNAs (miRNAs) play critical roles in plant responses to biotic and abiotic stresses at the post-transcriptional level. Although some miRNAs have been identified in maize, little is known about the miRNAs that accumulate differently in the response to chilling stress. In this paper, we combined Illumina sequencing with Northern blot to identify chilling-responsive miRNAs in maize. Novel miRNAs (36) were predicted and some were validated. Twenty-eight known miRNAs and 24 novel miRNAs were found to be differentially expressed under various chilling (6 ºC) treatment times, and most of them were down-regulated after the chilling treatments. Northern blot and real time quantitative polymerase chain reaction proved that miR408b and miRn138 were up-regulated, miR168a, miR529, miRn120, miRn44, and miRn22 were down-regulated, miR166b, miR396c, and miRn59 undulated under 2, 6, and 12 h of the chilling stress. Analysis agriGO based on the target genes of differentially expressed miRNAs indicates that it might change hydrolase and phosphatase activities, nucleic acid metabolisms, and many cellular components to adapt to the chilling stress.

Keywords

• gene expression
• illumina sequencing
• northern blot
• real time-qpcr
• zea mays