title: The far-upstream regulatory region of RFL is required for its precise spatial-temporal expression for floral development in rice.
abstract: A rice mutant aberrant floral organ 1 (afo1) was identified, showing increased floral organ number, aberrant floral organ identity and loss of floral meristem determinacy. A disruption of sequence integrity at 6292-bp upstream of RFL by a T-DNA insertion led to varied RFL expression patterns in floral meristem and floret in afo1 and caused the mutant phenotype. The LEAFY (LFY) transcription factor and its homologs affect many aspects of plant development, especially floral development. RICE FLORICAULA/LEAFY (RFL), the rice ortholog of LFY, has complicated expression patterns and different functions in floral development. However, the mechanisms regulating the spatial-temporal expression of RFL remain largely unknown. Here, we describe a rice aberrant floral organ 1 (afo1) mutant that was produced by a T-DNA insertion at 6292-bp upstream of the start codon of RFL. This insertion altered the expression of RFL in floral meristem (FM) and floret. The in situ hybridization result showed that, when florets appear, RFL was expressed almost exclusively at the palea/lemma adaxial base adjacent to lodicules in the wild-type panicle. However, in afo1 florets, RFL mRNA signals were detected in the region between lodicule and stamen, and strong signals persisted in FM. The altered pattern of RFL expression in afo1 resulted in enlarged FMs, more floral organs, aberrant floral organ identity, and loss of FM determinacy. Transformation of rice with an RFL construct driven by the 6292-bp upstream genomic sequence re-built the mutant phenotype similar to afo1. The results suggest that the far-upstream region of RFL may contain potential cis element(s) that are critical to define the precise spatial-temporal expression pattern of RFL for its function in floral development.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.|Guangdong Engineering Research Centre for Marine Algal Biotechnology, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Shenzhen University, Shenzhen, 518060, China.
authors.forename: Sulin
authors.initials: S
authors.lastname: Lou
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Shuifu
authors.initials: S
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China.|Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou, 510642, China.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Xiucai
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China.|Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou, 510642, China.|Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, South China Agricultural University, Guangzhou, 510642, China.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Letian
authors.initials: L
authors.lastname: Chen
authors.affiliation: College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Hongxiang
authors.initials: H
authors.lastname: Fu
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China. ygliu@scau.edu.cn.|Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou, 510642, China. ygliu@scau.edu.cn.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China. ygliu@scau.edu.cn.
authors.forename: Yao-Guang
authors.initials: YG
authors.lastname: Liu
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, 510642, China. pcb2000@scau.edu.cn.|Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions, South China Agricultural University, Guangzhou, 510642, China. pcb2000@scau.edu.cn.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China. pcb2000@scau.edu.cn.
authors.forename: Yuanling
authors.initials: Y
authors.lastname: Chen
mesh_terms: D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D018519:Meristem; D008855:Microscopy, Electron, Scanning; D016297:Mutagenesis, Site-Directed; D012275:Oryza / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D010641:Phenotype; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D012045:Regulatory Sequences, Nucleic Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000502:physiology
chemical_list: C111245:FL protein, Oryza sativa; D010940:Plant Proteins; D014157:Transcription Factors
keywords: Far-upstream regulatory element; Floral development; RFL; Rice