15th International Conference on Arabidopsis Research - TAIR

T01-083
Identification of Genes Required for Embryo
Development in Arabidopsis
Iris Tzafrir(1), Allan Dickerman(2), Colleen Sweeney(1), Steven Hutchens(1),
Sandrine Casanova(1), Amy Fesler(1), Clay Holley(1), John McElver(3, 4), George
Aux(3), David Patton(3), David Meinke(1)
1-Department of Botany, Oklahoma State University, Stillwater, OK 74078, USA
2-Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
3-Syngenta Biotechnology, Inc., Research Triangle Park, NC 27709, USA
4-BASF Plant Science, Research Triangle Park, NC 27709, USA
A long-term goal of Arabidopsis research is to define the minimal gene set
needed to produce a viable plant with a normal phenotype under diverse
conditions. This will require both forward and reverse genetics along with novel
strategies to characterize multigene families and redundant biochemical
pathways. Here we describe an initial dataset of 250 EMB genes required for
normal embryo development in Arabidopsis. This represents the first largescale
dataset of essential genes in a flowering plant. Analysis of these genes
has been the primary objective of our NSF 2010 Project (www.seedgenes.
org). When compared with 550 genes with other knockout phenotypes,
EMB genes are enriched for basal cellular functions, deficient in transcription
factors and signaling components, have fewer paralogs, and are more likely
to have counterparts among essential genes of yeast and worm. EMB genes
also represent a valuable source of plant-specific proteins with unknown
functions required for growth and development. Many of the estimated
500-1000 EMB genes in Arabidopsis have nevertheless escaped detection
to date. Based on sequence comparison with essential genes in other model
eukaryotes, we have identified 244 candidate EMB genes without paralogs
that represent promising targets for reverse genetics. Salk lines containing
insertions within these genes are currently being screened for seed defects.
These efforts should facilitate the recovery of additional genes required for
embryo development in Arabidopsis.
Funded by the NSF 2010 Program and the S.R. Noble Foundation.
T01 Development 1 (Flower, Fertilization, Fruit, Seed)
T01-084
Disruption of abh1, the Arabidopsis mRNA cap
binding protein, causes early flower development by
affecting the transcript abundance of photoperiod
and vernalization pathway regulators.
Josef M. Kuhn(1), Julian I. Schroeder(1)
1-Division of Biological Sciences, Section of Cell and Developmental Biology, University of California
San Diego, 9500 Gilman Drive, La Jolla, California 92093-116, USA
ABH1 encodes the large subunit of a dimeric Arabidopsis mRNA cap binding
complex (CBP80) and its mutation in the Col ecotype causes ABA-hypersensitive
regulation of seed germination, stomatal closing and cytosolic calcium
increases in guard cells (Hugouvieux et al., 2001, Cell 106, 477-487).
Abh1 disruption in the C24 ecotype also results in ABA hypersensitive seed
germination and stomatal closure. Moreover, abh1 plants in the C24 ecotype
exhibit an early flowering phenotype under long day and short day growth
conditions. Both mutant and wildtype plants respond to stepwise prolonged
cold treatment by gradually reducing rosette leaf numbers to an equal
quantity at the time of flowering. A semi quantitative RT-PCR approach on
RNA isolated from untreated and cold treated plants identified changes in the
transcript abundance of key regulators of flowering time in the photoperiod
and vernalization pathways. Intron specific RT-PCR analyses revealed no
significant influence of abh1 on pre mRNA maturation processes of flowering-associated
MADS box transcription factors. A model for abh1 effect on
flowering time will be presented, in which modulation of transcript levels of
positive and negative regulators affect the flowering promotion network.
15 th <strong>International</strong> <strong>Conference</strong> on Arabidopsis Research 2004 · Berlin