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Dr Katja Jaeger-Wigge

Abstract:

Environmental signal transduction in plants: insights from a new monocot model system. The floral transition is a key developmental decision. Plants integrate multiple environmental cues, including temperature, photoperiod and light quality to flower in the correct season [1]. Previously we have shown in Arabidopsis thaliana that a mobile signal is generated in the leaves in response to long photoperiods and this moves to the apex where it triggers flowering [1-3].   While the control of flowering in dicots, particularly Arabidopsis thaliana, is well understood, the mechanisms underlining floral induction in monocots are less clear. This is because it has been very difficult to study monocots due to their long generation times and large, unsequenced genomes. We are therefore using Brachypodium distachyon to study plant genome by environment interactions since it is an ideal model system with a small sequenced genome and excellent genetics and can be easily transformed.  Within the duration of rotation project we will use forward genetics to identify new players in the flowering pathway of monocots. Interesting mutants will be characterized, and mapping populations generated. Advances in Next-generation sequencing now make it feasible to identify causal mutations within the time frame of a PhD program, which is an enormous advance and presents a great opportunity. Techniques routinely used for mutant analysis include gene expression studies by quantitative RT-PCR, spatial expression analysis by RNA probe in situ hybridisation, transcriptome analysis (RNA Seq) and, where relevant, Chromatin Immunopurification coupled with next-generation sequencing (ChIP Seq).   We shall iteratively test hypotheses for the regulation of  flowering time  in Brachypodium using modelling approaches which we have pioneered in Arabidopsis [4]. The resulting models will be further elaborated to predict the influence of environmental signals like day length and temperature on flowering time behaviour.

References:

  1. Jaeger, K.E., A. Graf, and P.A. Wigge, The control of flowering in time and space. J Exp Bot, 2006. 57(13): p. 3415-8.  
  2. Wigge, P.A., et al., Integration of spatial and temporal information during floral induction in Arabidopsis. Science, 2005. 309(5737): p. 1056-9.  
  3. Jaeger, K.E. and P.A. Wigge, FT protein acts as a long-range signal in Arabidopsis. Curr Biol, 2007. 17(12): p. 1050-4