Endogenous and synthetic microRNAs stimulate simultaneous, efficient, and localized regulation of multiple targets in diverse species.
Recent studies demonstrated that pattern formation in plants involves regulation of transcription factor families by microRNAs (miRNAs). To explore the potency, autonomy, target range, and functional conservation of miRNA genes, a systematic comparison between plants ectopically expressing pre-miRNAs and plants with corresponding multiple mutant combinations of target genes was performed. We show that regulated expression of several Arabidopsis thaliana pre-miRNA genes induced a range of phenotypic alterations, the most extreme ones being a phenocopy of combined loss of their predicted target genes. This result indicates quantitative regulation by miRNA as a potential source for diversity in developmental outcomes. Remarkably, custom-made, synthetic miRNAs vectored by endogenous pre-miRNA backbones also produced phenocopies of multiple mutant combinations of genes that are not naturally regulated by miRNA. Arabidopsis-based endogenous and synthetic pre-miRNAs were also processed effectively in tomato (Solanum lycopersicum) and tobacco (Nicotiana tabacum). Synthetic miR-ARF targeting Auxin Response Factors 2, 3, and 4 induced dramatic transformations of abaxial tissues into adaxial ones in all three species, which could not cross graft joints. Likewise, organ-specific expression of miR165b that coregulates the PHABULOSA-like adaxial identity genes induced localized abaxial transformations. Thus, miRNAs provide a flexible, quantitative, and autonomous platform that can be employed for regulated expression of multiple related genes in diverse species.
Alvarez
John Paul
JP
Department of Plant Sciences, Weizman Institute of Science, Rehovot, 76100, Israel.
Pekker
Irena
I
Goldshmidt
Alexander
A
Blum
Eyal
E
Amsellem
Ziva
Z
Eshed
Yuval
Y
D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D015536:Down-Regulation; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000502:physiology; D018749:RNA, Plant / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014026:Nicotiana / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D035683:MicroRNAs; D010940:Plant Proteins; D018749:RNA, Plant; D012319:RNA Polymerase II