Temporal regulatory role of miR156 during leaf development

The highly conserved plant microRNA, miR156, is an essential regulator for plant development. We found miR156 changed gradually during leaf development. To find how miR156 regulated genes temporally, we analyzed the transcriptome of old and young leaves from miR156-overexpressed and wild type plants. The results show that the gradual increase of miR156 regulates temporal changes of numerous gene expressions during leaf development. To identify genes whose expressions are affected or indirectly regulated by miR156, Affymetrix rice DNA chips were used to check the transcriptomes of old (Leaf 3) and young (Leaf 6) leaves from miR156 over-expression lines and wild type at the tillering stage. In this study, leaves on each tiller were numbered according to its emerging order, with L1 indicating the first developed leaf. Three wild type plants and three independent miR156-overexpressed plants were used for transcriptome analysis by microarray hybridization.