title: Sequence and ionomic analysis of divergent strains of maize inbred line B73 with an altered growth phenotype.
abstract: Maize (Zea mays) is the most widely grown crop species in the world and a classical model organism for plant research. The completion of a high-quality reference genome sequence and the advent of high-throughput sequencing have greatly empowered re-sequencing studies in maize. In this study, plants of maize inbred line B73 descended from two different sets of seed material grown for several generations either in the field or in the greenhouse were found to show a different growth phenotype and ionome under phosphate starvation conditions and moreover a different responsiveness towards mycorrhizal fungi of the species Glomus intraradices (syn: Rhizophagus irregularis). Whole genome re-sequencing of individuals from both sets and comparison to the B73 reference sequence revealed three cryptic introgressions on chromosomes 1, 5 and 10 in the line grown in the greenhouse summing up to a total of 5,257 single-nucleotide polymorphisms (SNPs). Transcriptome sequencing of three individuals from each set lent further support to the location of the introgression intervals and confirmed them to be fixed in all sequenced individuals. Moreover, we identified >120 genes differentially expressed between the two B73 lines. We thus have found a nearly-isogenic line (NIL) of maize inbred line B73 that is characterized by an altered growth phenotype under phosphate starvation conditions and an improved responsiveness towards symbiosis with mycorrhizal fungi. Through next-generation sequencing of the genomes and transcriptomes we were able to delineate exact introgression intervals. Putative de novo mutations appeared approximately uniformly distributed along the ten maize chromosomes mainly representing G:C -> A:T transitions. The plant material described in this study will be a valuable tool both for functional studies of genes differentially expressed in both B73 lines and for research on growth behavior especially in response to symbiosis between maize and mycorrhizal fungi.
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraβe 3, Stadt Seeland, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Mascher
authors.affiliation: Botanical Institute, Cologne Biocenter, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Zülpicherstrasse 47b, Cologne, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Gerlach
authors.affiliation: Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraβe 31, Regensburg, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Gahrtz
authors.affiliation: Botanical Institute, Cologne Biocenter, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Zülpicherstrasse 47b, Cologne, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Bucher
authors.affiliation: Department of Cytogenetics and Genome Analysis, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstraβe 3, Stadt Seeland, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Scholz
authors.affiliation: Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraβe 31, Regensburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dresselhaus
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D023281:Genomics; D059014:High-Throughput Nucleotide Sequencing; D018895:Microsatellite Repeats / Q000235:genetics; D038821:Mycorrhizae / Q000235:genetics / Q000472:pathogenicity; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D003313:Zea mays / Q000235:genetics* / Q000382:microbiology