Upload
griselda-osborne
View
216
Download
1
Tags:
Embed Size (px)
Citation preview
Abstract
Auxin Evo-Devo: Genetic and Genomic Approaches to Understanding the Role of Auxin in Shoot Development
Auxin regulates nearly every aspect of plant growth and development. A better understanding of auxin’s function is therefore fundamentally important to basic plant biology and crop improvement. Previous research has demonstrated both conservation and diversification of auxin’s role in maize and Arabidopsis. This project will further our understanding of how auxin regulates shoot development, emphasizing maize shoot organogenesis. To identify additional genes functioning in auxin-mediated organogenesis, we are characterizing 147 maize mutants with distinctive vegetative and reproductive developmental defects. Together with previously characterized mutants, we have mapped 71 mutants to 40 locations in the maize genome. Eight of these loci had been cloned previously, and an additional six genes have been cloned on this project. Many of these genes encode proteins required for auxin biosynthesis, transport, and response. Preliminary phylogenetic analyses of 15 gene families have illustrated complex relationships amongst monocot and eudicot clades. Reverse genetic efforts guided by these phylogenetic relationships have confirmed 18 insertions in 12 genes. Further phylogenetic, functional and comparative expression analyses will test the conservation and diversification of auxin action mechanisms in all flowering plants.
Arabidopsis Maize Protein Function
taa1 vanishing tassel 2 (vt2)Tryptophan amino-
transferaseAuxin biosynthesis
yucca (yuc)sparse inflorescence1
(spi1)Flavin mono-oxygenase Auxin biosynthesis
pinformed1 (pin1) ZmPIN1a,b,c Auxin efflux carrier Auxin Transport
pinoid (pid) barren inflorescence2 (bif2)Serine threonine protein
kinaseAuxin Transport
naked pins in yucca (npy)
ZmNPY BTB-POZ-NPH3 Auxin signaling?
monopteros (mp) Zmmp2/10 Auxin Response Factor Auxin signal transduction
Aux/IAA ZmAux/IAAAux/IAA transcription
factorAuxin signal transduction
topless (tpl) ramosa enhancer2 (rel2)Transcriptional co-
repressorAuxin signal transduction
Rox1 barren stalk1 (ba1)bHLH transcription
factorAuxin response
? barren stalk2 (ba2)Protein interaction
domainAuxin response
nip5;1 tassel-less1 (tls1) Major intrinsic protein Membrane transport
bor1 rotten ear1 (rte1) Efflux transporter Membrane transport
thi1 tassel-less3 (tls3) Thiazole biosynthesis Thiamine biosynthesis
Mutants with a pin phenotype in Arabidopsis and a barren phenotype in maize
Arabidopsis Maize
AcknowledgementsWe thank Gerry Neuffer and the Maize Inflorescence Project for generating the mutants, the Maize Coop for providing the seed, Lu Gao, Mitzi Wilkening and Pat Schnable at Iowa State University for Sequenom analysis. This research was supported by the National Science Foundation grant number IOS 0820729/1114484.
Auxin is essential for shoot development
Jacob R. Withee1, Paula C. McSteen1, Simon T. Malcomber2, Andrea Gallavotti3, Yunde Zhao4, Naomi Altman5, Reka Albert6
1 Division of Biological Sciences, University of Missouri. Columbia, MO 65211. 2 Department of Biological Sciences, California State University. Long Beach, CA, 90840. 3 The Waksman Institute of Microbiology, Rutgers University. Piscataway, NJ 08854. 4 Section of Cell and Developmental Biology, University of California, San Diego. La Jolla, CA 92093. 5 Department of Statistics, The Pennsylvania State University. University Park, PA 16802. 6 Department of Physics, The Pennsylvania State University. University Park, PA 16802.
Reverse genetics: Confirmed Mu insertions
• Relative, qualitative gene expression for maize vt2 gene family determined from in silico analysis
• The vt2 and TAA1 clades are broadly expressed• Duplicate genes are expressed at a lower level• ZmTAR1/OsTAR1 clade is endosperm and seed specific
TAR1TAA1
TAR2
TAR3
vt2
ZmTAR1
ZmTAR1 dup
vt2 dup
TAR4
OsTAR1
ZmTAR3 ZmTAR4
vt2
du
p
Zm
TA
R1
du
p
spi d
up
yuc1
0/1
1
bif2
du
p
bif2
pa
ralo
g
bif2
pa
ralo
g
Zm
PIN
1a
mp
2
mp
10
Au
xIA
A
NP
Y1
a0
1
2
3
Functional genomics of maize barren mutants
• Genetic analysis of 147 EMS-induced barren mutants (in progress)• Mapped mutants using Sequenom MassArray SNP detection (71 completed, 22 in progress)• Allelism test and sequence (in progress, 15 confirmed or cloned)• Map-based cloning of 10-15 mutants (6 cloned, 12 in progress)
Map location of 40 barren* mutants in maize (blue have been cloned, dark blue cloned on this project)
ba2Ba-ub*
blast
1 2 3 4 5 6 7 8 9 10
rte1
kn1
Bif3
ba2
lg2Baub*
Dvd1
Bif1
baf1rel2
ba1
tls1
bif2
spi1
tls3
br-ub
bif*
Bif4
br*
tls2
bl*
te1
bif*
tls6
tls4
bl*
dw*
vt*
smp*
ub*
bl*
smp*
bif*
tls5
tls3
bif*
br-ub*
Mutants being cloned
vanishing tassel 2 (vt2) phylogeny and gene expression patterns
OsTAR2
OsTAR3OsTAR4
Coleoptile or Hypocot
yl
Root
Seedlin
g
SAM/Veg
. Meristem
Internode/
Stem
Immatur
e Leaves
Mature Leaves
Inflorescenc
e Meristem
Panicle/ Inflorescenc
e
Flower
s
Tassel
Anthers or
Floral
Organs
Ear
Silks/
Stigma
Husk
LeafFruit
Seed
Endosperm
Embryo
Highly expressed
Not expressed
bif*
an1
tls7
bl*ba*
vt2
vt2 spi1 bif2 PIN ARF1 AUX/IAA
NPY
Auxin Biosynthesis Auxin Transport Auxin Signal Transduction