title: MicroRNA393 is involved in nitrogen-promoted rice tillering through regulation of auxin signal transduction in axillary buds.
abstract: Rice tillering has an important influence on grain yield, and is promoted by nitrogen (N) fertilizer. Several genes controlling rice tillering, which are regulated by poor N supply, have been identified. However, the molecular mechanism associated with the regulation of tillering based on N supply is poorly understood. Here, we report that rice microRNA393 (OsmiR393) is involved in N-mediated tillering by decreasing auxin signal sensitivity in axillary buds. Expression analysis showed that N fertilizer causes up-regulation of OsmiR393, but down-regulation of two target genes (OsAFB2 and OsTB1). In situ expression analysis showed that OsmiR393 is highly expressed in the lateral axillary meristem. OsmiR393 overexpression mimicked N-mediated tillering in wild type Zhonghua 11 (ZH11). Mutation of OsMIR393 in ZH11 repressed N-promoted tillering, which simulated the effects of limited N, and this could not be restored by supplying N fertilizer. Western blot analysis showed that OsIAA6 was accumulated in both OsmiR393-overexpressing lines and N-treated wild type rice, but was reduced in the OsMIR393 mutant. Therefore, we deduced that N-induced OsmiR393 accumulation reduces the expression of OsTIR1 and OsAFB2, which alleviates sensitivity to auxin in the axillary buds and stabilizes OsIAA6, thereby promoting rice tillering.
authors: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors: Xiang
authors: X
authors: Li
authors: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors: Kuaifei
authors: K
authors: Xia
authors: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Zhen
authors: Z
authors: Liang
authors: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Kunling
authors: K
authors: Chen
authors: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors: Caixia
authors: C
authors: Gao
authors: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors: Mingyong
authors: M
authors: Zhang
mesh_terms: D005308:Fertilizers; D007210:Indoleacetic Acids / Q000378:metabolism*; D018519:Meristem / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism*; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D005308:Fertilizers; D007210:Indoleacetic Acids; D035683:MicroRNAs; D018749:RNA, Plant; D009584:Nitrogen