title: Gradual increase of miR156 regulates temporal expression changes of numerous genes during leaf development in rice.
abstract: The highly conserved plant microRNA, miR156, is an essential regulator for plant development. In Arabidopsis (Arabidopsis thaliana), miR156 modulates phase changing through its temporal expression in the shoot. In contrast to the gradual decrease over time in the shoot (or whole plant), we found that the miR156 level in rice (Oryza sativa) gradually increased from young leaf to old leaf after the juvenile stage. However, the miR156-targeted rice SQUAMOSA-promoter binding-like (SPL) transcription factors were either dominantly expressed in young leaves or not changed over the time of leaf growth. A comparison of the transcriptomes of early-emerged old leaves and later-emerged young leaves from wild-type and miR156 overexpression (miR156-OE) rice lines found that expression levels of 3,008 genes were affected in miR156-OE leaves. Analysis of temporal expression changes of these genes suggested that miR156 regulates gene expression in a leaf age-dependent manner, and miR156-OE attenuated the temporal changes of 2,660 genes. Interestingly, seven conserved plant microRNAs also showed temporal changes from young to old leaves, and miR156-OE also attenuated the temporal changes of six microRNAs. Consistent with global gene expression changes, miR156-OE plants resulted in dramatic changes including precocious leaf maturation and rapid leaf/tiller initiation. Our results indicate that another gradient of miR156 is present over time, a gradual increase during leaf growth, in addition to the gradual decrease during shoot growth. Gradually increased miR156 expression in the leaf might be essential for regulating the temporal expression of genes involved in leaf development.
authors.affiliation: National Key Laboratory for Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Kabin
authors.initials: K
authors.lastname: Xie
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Shen
authors.forename: Xin
authors.initials: X
authors.lastname: Hou
authors.forename: Jialing
authors.initials: J
authors.lastname: Yao
authors.forename: Xianghua
authors.initials: X
authors.lastname: Li
authors.forename: Jinghua
authors.initials: J
authors.lastname: Xiao
authors.forename: Lizhong
authors.initials: L
authors.lastname: Xiong
mesh_terms: D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D019441:Plant Epidermis / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome
chemical_list: D035683:MicroRNAs; D010940:Plant Proteins; D018749:RNA, Plant; D014157:Transcription Factors