National Plant Phenomics Centre

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  • Determining phenological patterns associated with the onset of senescence in a wheat MAGIC mapping population

    Determining phenological patterns associated with the onset of senescence in a wheat MAGIC mapping population

    Camargo-Rodriguez, A., Mott, R., Kim, J. T., Bentley, A., Mackay, I. J., Gardner, K., Doonan, J. & Corke, F. 30 Sep 2016 In : Frontiers in Plant Science. 7, 1540

    Abstract:

    The appropriate timing of developmental transitions is critical for adapting many crops to their local climatic conditions. Therefore, understanding the genetic basis of different aspects of phenology could be useful in highlighting mechanisms underpinning adaptation, with implications in breeding for climate change. For bread wheat (Triticum aestivum), the transition from vegetative to reproductive growth, the start and rate of leaf senescence and the relative timing of different stages of flowering and grain filling all contribute to plant performance. In this study we screened under Smart house conditions a large, multi-founder “NIAB elite MAGIC” wheat population, to evaluate the genetic elements that influence the timing of developmental stages in European elite varieties. This panel of recombinant inbred lines was derived from eight parents that are or recently have been grown commercially in the UK and Northern Europe. We undertook a detailed temporal phenotypic analysis under Smart house conditions of the population and its parents, to try to identify known or novel Quantitative Trait Loci associated with variation in the timing of key phenological stages in senescence. This analysis resulted in the detection of QTL interactions with novel traits such the time between “half of ear emergence above flag leaf ligule” and the onset of senescence at the flag leaf as well as traits associated with plant morphology such as stem height. In addition, strong correlations between several traits and the onset of senescence of the flag leaf were identified. This work establishes the value of systematically phenotyping genetically unstructured populations to reveal the genetic architecture underlying morphological variation in commercial wheat.

    http://journal.frontiersin.org/article/10.3389/fpls.2016.01540/full

  • eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and is Modulated by Phosphorylatio

    eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and is Modulated by Phosphorylation

    Bush, M. S., Pierrat, O., Nibau, C., Mikitova, V., Zheng, T., Corke, F. M. K., Vlachonasios, K., Mayberry, L. K., Browning, K. S. & Doonan, J. Sep 2016 In : Plant Physiology. 172, 1, p. 128-140 13 p.

    Abstract:

    eIF4A is a highly conserved RNA-stimulated ATPase and helicase involved in the initiation of mRNA translation. Previously, we found that eukaryotic initiation factor (eIF) 4A interacts with cyclin dependent kinase A (CDKA), the plant ortholog of mammalian CDK1. Here we show that this interaction occurs only in proliferating cells where the two proteins co-associate with 5′-cap-binding protein complexes, eIF4F or the plant specific eIFiso4F. CDKA phosphorylates eIF4A on a conserved threonine residue (T164) within the RNA-binding motif 1b “TPGR”. In vivo, a phospho-null (APGR) variant of the Arabidopsis eIF4A1 protein retains the ability to functionally complement a mutant (eif4a1) plant line lacking eIF4A1, whereas a phosphomimetic (EPGR) variant fails to complement. The phospho-null variant (APGR) rescues the slow growth rate of roots and rosettes, together with the ovule abortion and late flowering phenotypes. In vitro, wild type recombinant eIF4A1 and its phospho-null variant both support translation in cell free wheat germ extracts dependent upon eIF4A, but the phosphomimetic variant does not support translation and was also deficient in ATP hydrolysis and helicase activity. These observations suggest a mechanism whereby CDK phosphorylation has the potential to down regulate eIF4A activity and thereby affect translation.