10.5061/DRYAD.MQ5CT
Chantha, Sier-Ching
McGill University
Herman, Adam C.
McGill University
Platts, Adrian E.
McGill University
Vekemans, Xavier
Schoen, Daniel J.
McGill University
Data from: Secondary evolution of a self-incompatibility locus in the
Brassicaceae genus Leavenworthia
Dryad
dataset
2013
Leavenworthia
Arabidopsis
neo-functionalization
complex character
Dollo's Law
Leavenworthia alabamica
Comparative genomics
Arabidopsis lyrata
S-locus
Brassica
Capsella
Sisymbrium
pollen ligand
outcrossing
self-pollination
Brassicaceae
alignment
receptor kinase
2013-06-05T19:47:47Z
2013-06-05T19:47:47Z
en
https://doi.org/10.1371/journal.pbio.1001560
212540 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Self-incompatibility (SI) is the flowering plant reproductive system in
which self pollen tube growth is inhibited, thereby preventing
self-fertilization. SI has evolved independently in several different
flowering plant lineages. In all Brassicaceae species in which the
molecular basis of SI has been investigated in detail, the product of the
S-locus receptor kinase (SRK) gene functions as receptor in the initial
step of the self pollen-rejection pathway, while that of the S-locus
cysteine-rich (SCR) gene functions as ligand. Here we examine the
hypothesis that the S locus in the Brassicaceae genus Leavenworthia is
paralogous with the S locus previously characterized in other members of
the family. We also test the hypothesis that self-compatibility in this
group is based on disruption of the pollen ligand-producing gene. Sequence
analysis of the S-locus genes in Leavenworthia, phylogeny of S alleles,
gene expression patterns, and comparative genomics analyses provide
support for both hypotheses. Of special interest are two genes located in
a non-S locus genomic region of Arabidopsis lyrata that exhibit domain
structures, sequences, and phylogenetic histories similar to those of the
S-locus genes in Leavenworthia, and that also share synteny with these
genes. These A. lyrata genes resemble those comprising the A. lyrata S
locus, but they do not function in self-recognition. Moreover, they appear
to belong to a lineage that diverged from the ancestral Brassicaceae
S-locus genes before allelic diversification at the S locus. We
hypothesize that there has been neo-functionalization of these
S-locus-like genes in the Leavenworthia lineage, resulting in evolution of
a separate ligand-receptor system of SI. Our results also provide support
for theoretical models that predict that the least constrained pathway to
the evolution of self-compatibility is one involving loss of pollen gene
function.
Lal2/SRK alignment for entire coding sequenceNexus-formatted alignment of
the full coding sequence for SRK and Lal2 sequences included in Figure
2-A. Includes commands used for phylogenetic inference in
mrbayes.lal2_srk_all.nexLal2/SRK alignment for S-domain coding
sequenceNexus-formatted alignment of the S-domain coding sequence for SRK
and Lal2 sequences included in Figure S3-A. Includes commands used for
phylogenetic inference in mrbayes.lal2_srk_sdom.nexLal2/SRK alignment for
coding sequence excluding S-domainNexus-formatted alignment of the coding
sequence excluding the S-domain for SRK and Lal2 sequences included in
Figure S3-B. Includes commands used for phylogenetic inference in
mrbayes.lal2_srk_rest.nex