title: Soybean miR172c targets the repressive AP2 transcription factor NNC1 to activate ENOD40 expression and regulate nodule initiation.
abstract: MicroRNAs are noncoding RNAs that act as master regulators to modulate various biological processes by posttranscriptionally repressing their target genes. Repression of their target mRNA(s) can modulate signaling cascades and subsequent cellular events. Recently, a role for miR172 in soybean (Glycine max) nodulation has been described; however, the molecular mechanism through which miR172 acts to regulate nodulation has yet to be explored. Here, we demonstrate that soybean miR172c modulates both rhizobium infection and nodule organogenesis. miR172c was induced in soybean roots inoculated with either compatible Bradyrhizobium japonicum or lipooligosaccharide Nod factor and was highly upregulated during nodule development. Reduced activity and overexpression of miR172c caused dramatic changes in nodule initiation and nodule number. We show that soybean miR172c regulates nodule formation by repressing its target gene, Nodule Number Control1, which encodes a protein that directly targets the promoter of the early nodulin gene, ENOD40. Interestingly, transcriptional levels of miR172c were regulated by both Nod Factor Receptor1α/5α-mediated activation and by autoregulation of nodulation-mediated inhibition. Thus, we established a direct link between miR172c and the Nod factor signaling pathway in addition to adding a new layer to the precise nodulation regulation mechanism of soybean.
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China.
authors.forename: Youning
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Lixiang
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China.
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Zou
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Cai
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Senlei
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China.
authors.forename: Yinping
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: Centre for Integrative Legume Research, University of Queensland, Brisbane St. Lucia, Queensland 4072, Australia.
authors.forename: Brett J
authors.initials: BJ
authors.lastname: Ferguson
authors.affiliation: Centre for Integrative Legume Research, University of Queensland, Brisbane St. Lucia, Queensland 4072, Australia.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Gresshoff
authors.affiliation: Key State Laboratory of Plant Cell and Chromosome Engineering, Center of Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, Hebei 050021, China xli@genetics.ac.cn.
authors.forename: Xia
authors.initials: X
authors.lastname: Li
mesh_terms: D001483:Base Sequence; D020369:Bradyrhizobium / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D055170:Plant Root Nodulation / Q000235:genetics*; D053204:Root Nodules, Plant / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017423:Sequence Analysis, RNA; D015398:Signal Transduction; D013025:Glycine max / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D035683:MicroRNAs; D014157:Transcription Factors