15th International Conference on Arabidopsis Research - TAIR

T01-085
Patterns of Gene Expression during Arabidopsis
Flower Development
Frank Wellmer(1), Marcio Alves-Ferreira(1, 2), Annick Dubois(1), Jose Luis
Riechmann(1), Elliot M. Meyerowitz(1)
1-California Institute of Technology, Division of Biology, Pasadena, CA 91125, USA
2-Federal University of Rio de Janeiro, Department of Genetics, Rio de Janeiro, Brazil
We are using DNA microarrays to identify genes that are expressed only at
certain stages during flower development or specifically in certain parts of the
flower. These spatially and/or temporally regulated genes may play important
roles in the regulatory processes that pattern the flower or in the differentiation
of the various floral cell types. We have initiated our study by comparing
the gene expression profiles of wild-type flowers with those of mutants that
show homeotic transformations. In these homeotic mutants, certain types of
floral organs are absent or are replaced by other types of organs. By combining
the data sets obtained from these experiments, we were able to identify
a large number of genes that are specifically expressed or are strongly
enriched in one of the four different types of floral organs.
We are also trying to identify the target genes of several of the many
transcription factors that have been implicated in flower development. To this
end, we have generated inducible systems that allow us to do time-course
experiments and to observe changes in gene expression that occur shortly
after the activation of the factors as well as later changes that are presumably
downstream of the primary events.
15 th <strong>International</strong> <strong>Conference</strong> on Arabidopsis Research 2004 · Berlin
T01-086
Novel developmental mutants of Arabidopsis thaliana
Mirza, J. I.(1)
1-Institute of Biology, Bahauddin Zakariya University, Multan, Pakistan
A number of interesting developmental mutants of Arabidopsis thaliana (Ler)
were isolated following mutagenization with ethylmethane sulphonate. These
mutants were initially screened on the basis of resistance to spermine, NAA
or BA, but many of these exhibited no resistance in next generations. The
phenotypes of these mutants included a number of developmental abnormalities
affecting all growth stages from seed germination to seed formation,
such as aberrant seed development, altered seed shape, transparent testa,
vivipary, affected root and/or hypocotyls gravitropism, absence or abundance
of root hair, short root hair, long hypocotyls, 1-3 cotyledons, dwarf or
semi-dwarf stature, spirally-twisted growth of whole shoot, variation in leaf
shape/size, twisting of rosette and cauline leaves, absence of trichomes,
increased number of leaves, inflorescences and lateral branches, reduced
apical dominance, malformed flowers, variation in the number and size of
floral organs, homeotic conversions of floral organs, male or female sterility,
reduced number of stigmatic hair, bifid or sunken stigma, crinkled or clubshaped
to globose siliques, and pendulant or horizontal siliques. The phenotypes
of these mutants are controlled by single recessive nuclear mutations.
Some of the mutants are allelic to existing ones; others appear to be unique.
Consequently, 12 mutant phenotype symbols have been registered with TAIR.
T01 Development 1 (Flower, Fertilization, Fruit, Seed)