RESUMO
Cell cycle regulators are crucial for normal endosperm development and seed size determination. However, how the cell cycle related genes regulate endosperm development remains unclear. In this study, we reported a rice Nuclear Factor Y (NF-Y) gene OsNF-YB1, which was also identified as an endosperm-specific gene. Transcriptional profiling and promoter analysis revealed that OsNF-YB1 was highly expressed at the early stages of rice endosperm development (5-7 DAP, days after pollination). Repression of OsNF-YB1 resulted in differential expression of the genes in cell cycle pathway, which caused abnormal seeds with defected embryo and endosperm. Basic cytological analysis demonstrated that the reduced endosperm cell numbers disintegrated with the development of those abnormal seeds in OsNF-YB1 RNAi plants. Taken together, these results suggested that the endosperm-specific gene OsNF-YB1 might be a cell cycle regulator and played a role in maintaining the endosperm cell proliferation.
Assuntos
Proliferação de Células , Endosperma/genética , Oryza/genética , Proteínas de Plantas/genética , Ciclo Celular/genética , Endosperma/citologia , Endosperma/embriologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Microscopia de Fluorescência , Oryza/citologia , Oryza/embriologia , Filogenia , Proteínas de Plantas/classificação , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/genética , Fatores de TempoRESUMO
The endosperm of the cereal crop is an important nutrient source for humans. It also acts as a critical integrator of plant seed growth and development. Despite its importance, the comprehensive understanding in regulating of endosperm development in rice remains elusive. Here, we performed a genomic survey comprising the identification and functional characterization of the endosperm-specific genes (OsEnS) in rice using Affymetrix microarray data and Gene Ontology (GO) analysis. A total of 151 endosperm-specific genes were identified, and the expression patterns of 13 selected genes were confirmed by qRT-PCR analysis. Promoter regions of the endosperm-specific expression genes were analyzed by PLACE Signal Scan Search. The results indicated that some motifs were involved in endosperm-specific expression regulation, and some cis-elements were responsible for hormone regulation. The bootstrap analysis indicated that the RY repeat (CATGCA box) was over-represented in promoter regions of endosperm-specific expression genes. GO analysis indicated that these genes could be classified into 12 groups, namely, transcription factor, stress/defense, seed storage protein (SSP), carbohydrate and energy metabolism, seed maturation, protein metabolism, lipid metabolism, transport, cell wall related, hormone related, signal transduction, and one unclassified group. Taken together, our results provide informative clues for further functional characterization of the endosperm-specific genes, which facilitate the understanding of the molecular mechanism in rice endosperm development.
Assuntos
Endosperma/genética , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Redes e Vias Metabólicas/genética , Oryza/genética , Mapeamento Cromossômico , Endosperma/metabolismo , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Análise de Sequência com Séries de Oligonucleotídeos , Oryza/metabolismo , Regiões Promotoras GenéticasRESUMO
Argonautes (AGOs) play crucial roles in RNAi and related pathways in several species and regulate plant growth and development. However the investigation in rice argonautes (OsAGOs) remains elusive. Here we focused on the expression pattern and co-expression profiles of OsAGO genes. Microarray-based and qRT-PCR expression profiling of 19 OsAGO genes indicated that most OsAGOs expressed specifically and preferentially during stages of reproductive development, and exhibited preferential up-regulation in panicle stages. Six OsAGO genes showed specific up/down-regulation in response to Gibberellin A3 (GA3), Kinetin (KT), or 1-Naphthaleneacetic acid (NAA) treatments. And three OsAGOs presented specific up-regulation in response to light and dark treatments. Ten OsAGOs were co-expressed with Dicer-like (DCL), Double-stranded RNA Binding (DRB) and RNA-dependent RNA polymerase (RDR) genes, which were related with RNA processing including RNAi pathways. Twelve OsAGOs were correlated with 17 kinds of transcription factors involving diverse functions. Four OsAGOs RNAi plants were constructed, the expression level of co-expression genes, including DCL3, DRB2, RDR4 etc., were changed while OsAGOs were down-regulated in RNAi lines, providing experimental evidence for co-expression networks. The results provide new insights in understanding the biological pathways of OsAGO genes, as well as in selecting the candidate genes involved in RNA silencing mechanisms.
