75 Integrating Membrane Transport with Male Gametophyte ... - TAIR

367 Natural Variation in Inflorescence Replacement in Arabidopsis
Cecile Sano 2 , Martin Bohn 3 , Ken Paige 1 , Thomas Jacobs 2
1
Department of Animal Biology, University of Illinois at Urbana-Champaign, 2 Department of Plant Biology,
University of Illinois at Urbana-Champaign, 3 Department of Crop Sciences, University of Illinois at Urbana-
Champaign
Animals ultimately obtain all their energy from plants. Herbivory therefore imposes an inevitable selection pressure on every
plant species' evolution. Reserving axillary meristems can reduce the fitness cost of losing reproductive structures to browsing
herbivores. When an Arabidopsis plant's primary inflorescence is removed or damaged, axillary buds can replace it by elongating
into axillary inflorescences. This phenomenon has long been known as apical dominance. We have adopted a quantitative genetic
approach in an effort to understand the genetic basis of the Arabidopsis Inflorescence Replacement Program (IRP) and its natural
phenotypic variation. We have begun by scoring the responses to apex removal of a geographically diverse collection of 90
Arabidopsis accessions. The primary inflorescence of each plant was clipped at its base when its first flower opened or when it
reached a height of 4 cm, whichever came first. Parameters scored included: days to flower (DFL), length of primary inflorescence
(APL) at clipping, days to re-flower after clipping (DRF), number of rosette leaves at the time of clipping (LFN), number of axillary
inflorescences 0.3 cm or longer on the day of clipping (ACL), and number of axillary inflorescences (ARF) and the length of each
(AXL) at the day of re-flowering. The day that the first axillary flower was fully opened was designated the day of re-flowering.
A randomized incomplete block design was used. Plot means based on four plants per plot and accession were calculated and
ANOVA, cluster analysis and principal component analysis (PCA) were performed. High heritability was seen for all measured
parameters. The parameter pairs DFL/DRF, DFL/LFN and DRF/LFN were positively correlated. AXL/DFL and ACL/DRF were
negatively correlated. Five major phenotypic clusters were identified within the 90 accessions. Within-cluster PCA suggests that
several distinct IRP strategies are discernable among the 90 accessions, with each IRP strategy composed of a uniquely weighted
combination of measured traits. Our hypothesis of differing IRP strategies across Arabidopsis germplasm is therefore supported by
this analysis. From these 90 accessions, we have selected for intercrossing a subset that represents varying and extreme IRP strategies.
QTL will be mapped for IRP component traits in segregating populations. This analysis will provide insights into the underlying
genetic basis, and its global variation, of an adaptive, and possibly co-evolving suite of traits in Arabidopsis. QTL identified may
also represent novel loci heretofore unidentified by conventional mutant analyses of branching and apical dominance.
368 The Arabidopsis Biological Resource Center – Current Acquisitions and Activities
Randy Scholl, Emma Knee, Luz Rivero, Deborah Crist, Natalie Case, Heather Joesting, Daniel Johnson, Kate
Ludwig, James Mann, Cori Phillips, Garret Posey, Pamela Vivian, Zhen Zhang, LIng Zhou
Arabidopsis Biological Resource Center, Dept. of Plant Cellular and Molecular Biology and Plant
Biotechnology Center, The Ohio State University
The Arabidopsis Biological Resource Center (ABRC) collects, preserves and distributes seed and DNA stocks
of Arabidopsis. ABRC stock information is in the TAIR (maintained by the Carnegie Institution of Washington, with
informatics support from the National Center for Genomic Resources) and stocks can be ordered at (http://arabidopsis.
org).
Seed stocks have been added to our collections in the past year, including: A) 1,900 confirmed, purified T-DNA lines
from J. Ecker; B) purified T-DNA insertion lines from researchers C) ca. 9,000 SAIL T-DNA from Syngenta, D) T-DNA
lines from GABI-Kat; E) RNAi lines from AGRIKOLA, F) mutant lines; G) a recombinant inbred population form J.
Borevitz; and H) miscellaneous transgenic lines. The T-DNA lines of the SALK, SAIL and Wisconsin collections provide
insertions in 25,000+ different Arabidopsis genes.
New DNA stocks added to the collection include: A) sequence-validated open Reading Frame (ORF) clones from J.
Ecker, B) ORF clones from C. Town; C) 1,100 Gateway Expression clones from S. P. Dinesh Kumar, D) multifunctional
vectors that utilize the Gateway TM system and E) Expression clones from different researchers. The present ORF and cDNA
collection represents 15,000+ genes. The SSP and Salk ORF collections have been formatted to plates and revalidated
by end sequencing.
During the past year, ABRC distributed 70,000 seed and 26,600 DNA stocks to researchers. Distribution of T-DNA lines
contribute to the very high number of seeds being sent, and the ORF clones represent the most popular DNA stocks.
ABRC is supported by the National Science Foundation.