title: The Evolution of Photoperiod-Insensitive Flowering in Sorghum, A Genomic Model for Panicoid Grasses.
abstract: Of central importance in adapting plants of tropical origin to temperate cultivation has been selection of daylength-neutral genotypes that flower early in the temperate summer and take full advantage of its long days. A cross between tropical and temperate sorghums [Sorghum propinquum (Kunth) Hitchc.×S. bicolor (L.) Moench], revealed a quantitative trait locus (QTL), FlrAvgD1, accounting for 85.7% of variation in flowering time under long days. Fine-scale genetic mapping placed FlrAvgD1 on chromosome 6 within the physically largest centiMorgan in the genome. Forward genetic data from "converted" sorghums validated the QTL. Association genetic evidence from a diversity panel delineated the QTL to a 10-kb interval containing only one annotated gene, Sb06g012260, that was shown by reverse genetics to complement a recessive allele. Sb06g012260 (SbFT12) contains a phosphatidylethanolamine-binding (PEBP) protein domain characteristic of members of the "FT" family of flowering genes acting as a floral suppressor. Sb06g012260 appears to have evolved ∼40 Ma in a panicoid ancestor after divergence from oryzoid and pooid lineages. A species-specific Sb06g012260 mutation may have contributed to spread to temperate regions by S. halepense ("Johnsongrass"), one of the world's most widespread invasives. Alternative alleles for another family member, Sb02g029725 (SbFT6), mapping near another flowering QTL, also showed highly significant association with photoperiod response index (P = 1.53×10 (-)  (6)). The evolution of Sb06g012260 adds to evidence that single gene duplicates play large roles in important environmental adaptations. Increased knowledge of Sb06g012260 opens new doors to improvement of sorghum and other grain and cellulosic biomass crops.
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia.
authors.forename: Hugo E
authors.initials: HE
authors.lastname: Cuevas
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia.
authors.forename: Chengbo
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, Fujian Province, China School of Plant Sciences, iPlant Collaborative, University of Arizona.
authors.forename: Haibao
authors.initials: H
authors.lastname: Tang
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia.
authors.forename: Prashant P
authors.initials: PP
authors.lastname: Khadke
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia.
authors.forename: Sayan
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Soil and Crop Sciences, Texas A&M University, College Station Department of Agronomy, National Taiwan University, Taipei, Taiwan.
authors.forename: Yann-Rong
authors.initials: YR
authors.lastname: Lin
authors.affiliation: Department of Agronomy and Horticulture, University of Nebraska, Lincoln.
authors.forename: Zhengxiang
authors.initials: Z
authors.lastname: Ge
authors.affiliation: Department of Agronomy and Horticulture, University of Nebraska, Lincoln.
authors.forename: Thomas
authors.initials: T
authors.lastname: Clemente
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India.
authors.forename: Hari D
authors.initials: HD
authors.lastname: Upadhyaya
authors.affiliation: International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India.
authors.forename: C Thomas
authors.initials: CT
authors.lastname: Hash
authors.affiliation: Plant Genome Mapping Laboratory, University of Georgia Department of Soil and Crop Sciences, Texas A&M University, College Station paterson@uga.edu.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Paterson
mesh_terms: D000483:Alleles; D005075:Biological Evolution; D002874:Chromosome Mapping / Q000379:methods; D032461:Chromosomes, Plant; D002523:Edible Grain / Q000235:genetics; D019143:Evolution, Molecular; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D020440:Gene Duplication; D017343:Genes, Plant; D023281:Genomics / Q000379:methods; D008957:Models, Genetic; D017440:Photoperiod; D010940:Plant Proteins / Q000235:genetics; D006109:Poaceae / Q000235:genetics; D040641:Quantitative Trait Loci; D045868:Sorghum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D010940:Plant Proteins
keywords: FT domain; Sorghum halepense (“Johnsongrass”); conversion; flowering; photoperiod; single gene duplication.