Australian Centre for Plant Functional Genomics publications

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Browsing Australian Centre for Plant Functional Genomics publications by Author "Able, J."

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    Genomics approaches to identify meiotic genes in wheat
    (2004) Sutton, T.; Whitford, R.; Baumann, U.; Able, J.; Lazo, G.; Langridge, P.; Plant & Animal Genomes Conference (12th : 2004 : San Diego, Calif.); Australian Centre for Plant Functional Genomics (ACPFG)
    In contrast to the recent advancements made in meiotic gene discovery for plants such as Arabidopsis, the progress for wheat has been difficult, hampered principally by a large, polyploid genome. We report here on genomics approaches to identify and characterise genes involved in meiosis in wheat. The first approach used comparative genetics to define the genic content of the 3DS region deleted in the pairing homoeologous mutant ph2a (a deletion mutant at the Ph2 locus). More than 200 genes linked to Ph2 have been identified, several as candidates for the Ph2 gene(s). The degree of synteny at the gene level in wheat and rice across the region analysed has been established in detail and the extent of the deleted segment in ph2a clarified. Furthermore, the spatial transcriptional characteristics of genes linked to Ph2 have been analysed using data from wheat expressed sequence tag (EST) databases in combination with recently developed analysis software. The second approach used a cDNA microarray derived from an anther library to examine gene expression in a temporal series experiment from pre-meiosis to the tetrad stage of meiotic development. We report on these results and their relevance to meiotic and anther developmental processes.
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    Identification of transposons, retroelements, and a gene family predominantly expressed in floral tissues in chromosome 3DS of the hexaploid wheat progenitor Aegilops tauschii
    (Springer-Verlag, 2007) Whitford, R.; Baumann, U.; Sutton, T.; Gumaelius, L.; Wolters, P.; Tingey, S.; Able, J.; Langridge, P.
    A multigene family expressed during early floral development was identified on the short arm of wheat chromosome 3D in the region of the Ph2 locus, a locus controlling homoeologous chromosome pairing in allohexaploid wheat. Physical, genetic and molecular characterisation of the Wheat Meiosis 1 (WM1) gene family identified seven members that localised within a region of 173-kb. WM1 gene family members were sequenced and they encode mainly type Ia plasma membrane-anchored leucine rich repeat-like receptor proteins. In situ expression profiling suggests the gene family is predominantly expressed in floral tissue. In addition to the WM1 gene family, a number of other genes, gene fragments and pseudogenes were identified. It has been predicted that there is approximately one gene every 19-kb and that this region of the wheat genome contains 23 repetitive elements including BARE-1 and Wis2-1 like sequences. Nearly 50% of the repetitive elements identified were similar to known transposons from the CACTA superfamily. Ty1-copia, Ty3-gypsy and Athila LTR retroelements were also prevalent within the region. The WM1 gene cluster is present on 3DS and on barley 3HS but missing from the A and B genomes of hexaploid wheat. This suggests either recent generation of the cluster or specific deletion of the cluster during wheat polyploidisation. The evolutionary significance of the cluster, its possible roles in disease response or floral and early meiotic development and its location at or near the Ph2 locus are discussed.
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    Microarray expression analysis of meiosis and microsporogenesis in hexaploid bread wheat
    (BioMed Central Ltd., 2006) Crismani, W.; Baumann, U.; Sutton, T.; Shirley, N.; Webster, T.; Spangenberg, G.; Langridge, P.; Able, J.
    Background: Our understanding of the mechanisms that govern the cellular process of meiosis is limited in higher plants with polyploid genomes. Bread wheat is an allohexaploid that behaves as a diploid during meiosis. Chromosome pairing is restricted to homologous chromosomes despite the presence of homoeologues in the nucleus. The importance of wheat as a crop and the extensive use of wild wheat relatives in breeding programs has prompted many years of cytogenetic and genetic research to develop an understanding of the control of chromosome pairing and recombination. The rapid advance of biochemical and molecular information on meiosis in model organisms such as yeast provides new opportunities to investigate the molecular basis of chromosome pairing control in wheat. However, building the link between the model and wheat requires points of data contact. Results: We report here a large-scale transcriptomics study using the Affymetrix wheat GeneChip® aimed at providing this link between wheat and model systems and at identifying early meiotic genes. Analysis of the microarray data identified 1,350 transcripts temporally-regulated during the early stages of meiosis. Expression profiles with annotated transcript functions including chromatin condensation, synaptonemal complex formation, recombination and fertility were identified. From the 1,350 transcripts, 30 displayed at least an eight-fold expression change between and including pre-meiosis and telophase II, with more than 50% of these having no similarities to known sequences in NCBI and TIGR databases. Conclusion: This resource is now available to support research into the molecular basis of pairing and recombination control in the complex polyploid, wheat.