title: EF8 is involved in photoperiodic flowering pathway and chlorophyll biogenesis in rice.
abstract: A DTH8/Ghd8 allele suppresses flowering by altering the expression patterns of the 'florigen' genes, but also negatively regulates chlorophyll biogenesis. Flowering time is a critical agronomic trait determining the growing season, regional adaptation and yield potential in rice (Oryza sativa L.). We characterized a mutant named early flowering 8 (ef8) selected from an ethyl methanesulfonate (EMS)-treated population of indica cultivar 93-11. It showed earlier flowering, less grains per main panicle and slightly darker green leaves than the wild-type 93-11 under natural long-day conditions, but was not significantly different from 93-11 under natural short-day conditions. We isolated the Early Flowering 8 (EF8) gene by map-based cloning. EF8 encodes a putative HAP3 subunit of the CCAAT-box-binding transcription factor, which is localized to the nucleus. EF8 was expressed in various tissues, especially in leaves, with a rhythmic expression pattern. Our data showed that EF8 delayed flowering time under long-day conditions by altering the rhythmic expression patterns of 'florigen' genes Hd3a and RFT1. We also found that EF8 negatively regulates the expression of chlorophyll biosynthetic genes to reduce the chlorophyll content. Our data indicate that EF8 plays an important role in rice photoperiodic flowering pathway as well as yield potential and chlorophyll biogenesis and will be an important target for rice breeding programs.
authors.affiliation: State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, 210095, China, fengzhiming88@163.com.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Feng
authors.forename: Long
authors.initials: L
authors.lastname: Zhang
authors.forename: Chunyan
authors.initials: C
authors.lastname: Yang
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Jia
authors.initials: J
authors.lastname: Lv
authors.forename: Yilin
authors.initials: Y
authors.lastname: Chen
authors.forename: Xi
authors.initials: X
authors.lastname: Liu
authors.forename: Shijia
authors.initials: S
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.forename: Jianmin
authors.initials: J
authors.lastname: Wan
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D003001:Cloning, Molecular; D060405:Florigen / Q000378:metabolism; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D009154:Mutation; D012275:Oryza / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D017440:Photoperiod; D020161:Physical Chromosome Mapping; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D060405:Florigen; D010940:Plant Proteins; D002734:Chlorophyll