15th International Conference on Arabidopsis Research - TAIR

T04-033
The location of QTL for nutrient stress and heavy
metal tolerance using Stepped Aligned Inbred
Recombinant Strains (STAIRS) in Arabidopsis
thaliana.
Ankush Prashar(1), T. M. Wilkes(1), J. Pritchard(1), M. J. Kearsey(1)
1-School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, U.K.
Nutrients play an important role in plant growth and development. They are
involved in many biochemical and biophysical processes but effects of heavy
metals on plants result in growth inhibition, structural damage and decline
of physiological and biochemical activities as well as function of plants. This
study is aimed at investigating the genetic basis of tolerance to low nutrient
stress and heavy metals in Arabidopsis thaliana and identifying the QTL’s that
regulate this tolerance. Heavy metals may enter plants through transporter
channels for mineral nutrients. Identification of QTLs underlying the tolerance
of low nutrient stress and heavy metals will be useful in selection for multiple
traits which include low nutrient tolerance and hyper accumulation of heavy
metals.
A novel form of NILS (Stepped Aligned Inbred Recombinant Strains) are being
used to differentiate the regions on the chromosome which affect the stress
tolerance in Arabidopsis(Koumprolglou et al, 2002).
Koumproglou et al (2002). The Plant Journal 31(3), 355 ¯ 364.
15 th <strong>International</strong> <strong>Conference</strong> on Arabidopsis Research 2004 · Berlin
T04-034
Characterisation of Integrators of Light Perception to
the Circadian Clock
Elsebeth Kolmos(1), Mark R. Doyle(2), Andras Viczian(3), Joachim Uhrig(4), Richard
M. Amasino(2), Ferenc Nagy(3), Seth J. Davis(1)
1-Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research,
Carl-von-Linne-Weg 10, D-50829 Cologne, Germany
2-Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
3-Institute of Plant Biology, Biological Research Center, P.O. Box 521, H¯6701, Hungary
4-Department of Plant Breeding and Genetics, Max Planck Institute for Plant Breeding Research,
Carl-von-Linne-Weg 10, D-50829 Cologne, Germany
In Arabidopsis thaliana, many metabolic and developmental processes
are circadian regulated. The outputs of the plant circadian system can be
monitored as overt rhythms at genetic, biochemical, and physiological levels.
Entrainment of the plant’s endogenous clock(s) is facilitated by means of light
perception. EARLY FLOWERING 3 (ELF3) and EARLY FLOWERING 4 (ELF4) are
believed to function in clock entrainment by integrating light signals. ELF3
and ELF4 are members of different gene families and the biochemical activity
of the encoded proteins is unknown. The phenotypes of elf3 and elf4 depend
on the light environment and both mutants show photoperiod-insensitive
flowering time as well circadian arrhythmicities. We isolated allelic series of
both ELF3 and ELF4 to obtain a gradient of mutants, including possible subtle
and gain-of-function alleles. These new mutant alleles are the basis for our
characterisation of ELF3 and ELF4. Molecular and physiological screens,
such as expression profiling of circadian-output genes and hypocotylelongation
assays, are carried out under specific light regimes. In parallel,
phylogenetics of ELF3 and ELF4 is applied to provide a link between aminoacid
conservation and functional significance of various protein domains. We
study biochemical modes-of-action of ELF3 and ELF4 using yeast two-hybrid
screens, which provide candidates of protein-protein interactions. Preys were
selected based on a circadian connection and/or flowering time. Protein
domains involved in interaction will be studied using site-directed mutagenesis
of elf3 and elf4. Interestingly, we selected EARLY FLOWERING 20 (EF20)
as an ELF4-interacting candidate. The ef20 mutant is under short-day growth
a long-hypocotyl and early-flowering mutant. This implicates EF20 in ELF4
signalling. Collectively, these genetic studies should place ELF3, ELF4, and
their interaction partners in appropriate signalling pathways.
T04 Interaction with the Environment 1 (Abiotic)