15th International Conference on Arabidopsis Research - TAIR

T07-009
Arabidopsis thaliana P450 transcript profiling and
functional genomics
Hui Duan(1), Shahjahan Ali(1), Sanjeewa Rupasinghe(1), Natanya Civjan(2), Jyothi
Thimmapuram(3), Lei Liu(3), Mark Band(3), Stephen Sligar(2), Daniele Werck-
Reichhart(4), Mary A. Schuler(1)
1-Department of Cell & Structural Biology, University of Illinois, Urbana, IL USA
2-Department of Biochemistry, University of Illinois, Urbana, IL USA
3-W.M. Keck Center for Comparative and Functional Genomics, University of Illinois, Urbana, IL
USA
4-Institute of Plant Molecular Biology, CNRS, Strasbourg, France
In plants, P450s function in the biosynthesis of lignins, pigments, defense
compounds, fatty acids, hormones and growth regulators as well as in the
metabolism of herbicides, insecticides and pollutants. Towards defining the
function of the 272 P450 genes existing in Arabidopsis, we have analyzed
microarrays containing gene-specific elements for 265 P450s, 40 biochemical
pathway markers and 322 physiological function markers for constitutively
expressed and chemically inducible P450 transcripts. This analysis has
highlighted a number of P450 transcripts expressed in most, if not all tissues,
under normal growth conditions and detailed the array of P450 transcripts
expressed in response to plant signaling molecules (JA, SA), fungal defense
activators (BTH) and environmental stresses (mannitol, cold). Together, these
analyses detail the unique and overlapping responses of P450 and biochemical
pathway loci to internal and external chemical cues. Heterologous
expression of P450s and P450 reductases in baculovirus-insect cell systems
have allowed us to co-incorporate these endoplasmic reticulum localized
enzymes into a soluble nanodisc system that is suitable for substrate binding
and turnover analysis as well as sorting and characterization of other membrane-bound
proteins. Molecular models have been developed for a number
of P450s whose substrate binding capacities have been defined by these
approaches.
15 th <strong>International</strong> <strong>Conference</strong> on Arabidopsis Research 2004 · Berlin
T07-010
P, A and L boxes do it together: A statistical approach
for the investigation on stress inducible cis-elements
in Arabidopsis
Kenneth Berendzen(1), Dierk Wanke(1, 2), Kurt Stüber(1), Björn Hamberger(1, 3)
1-Max-Planck-Institut for Plant Breeding Research and Yield Physiology; Carl-von-Linné Weg 10;
D-50829 Köln - Germany
2-Universität zu Köln; Lehrstuhl II; AG Harter; Gyrhofstr. 15; D-50931 Köln - Germany
3-University of British Columbia; Department of Botany; Vancouver, B.C.;
In the model plant A. thaliana, phenylpropanoid metabolism feeds the
biosynthesis from simple hydroxycinnamic acids, as soluble and wall-bound
phenolics, to lignin-precursors and complex flavonoids, isoflavonoids, and
anthocyanins. These products play important roles in plant structure and development,
as well as defense responses against biotic and abiotic stresses.
The enzymatic steps involved in the biosynthesis of phenylpropanoids are
increasingly well understood. Many of the corresponding genes have been
cloned, but knowledge about cis-acting elements mediating the response to
regulatory factors that orchestrate rapid, coordinated induction of phenylpropanoid
is sparse.
Boxes P and L , together with a frequent but variable co-occurring box A
may be involved in coordinated expression, were initially identified by in vivo
footprinting as UV and elicitor-responsive regions in the PAL1 gene promoter
of parsley.
Here we show that the recently identified At4CL4 gene promoter also
contains both P and L boxes at TATA proximal positions. Remarkably, these
two boxes occur in the same order as in the At4CL1¯3 and the initially studied
Pc4CL1¯2 gene promoters.
Genome wide scrutinizing of available promoter regions with MotifMapper
(www.motifmapper.de) helped identifying these boxes in many genes of the
phenolpropanoid pathway. Moreover, other promoters containing common
elements like the P, A or L-boxes putatively underlay similar regulation by the
same upstream transcription factors.
T07 Metabolism (Primary, Secondary, Cross-Talk and Short Distance Metabolite Transport)