BREAKDOWN OF SELF-INCOMPATIBILITY IN THE PERENNIAL ARABIDOPSIS LYRATA (BRASSICACEAE) AND ITS GENETIC CONSEQUENCES

Evolution ◽  
2005 ◽  
Vol 59 (7) ◽  
pp. 1437 ◽  
Author(s):  
Barbara K. Mable ◽  
Alexander V. Robertson ◽  
Sara Dart ◽  
Christina Di Berardo ◽  
Laura Witham
2021 ◽  
Vol 22 (13) ◽  
pp. 6990
Author(s):  
Shinsuke Yasuda ◽  
Risa Kobayashi ◽  
Toshiro Ito ◽  
Yuko Wada ◽  
Seiji Takayama

Self-incompatibility (SI) is conserved among members of the Brassicaceae plant family. This trait is controlled epigenetically by the dominance hierarchy of the male determinant alleles. We previously demonstrated that a single small RNA (sRNA) gene is sufficient to control the linear dominance hierarchy in Brassica rapa and proposed a model in which a homology-based interaction between sRNAs and target sites controls the complicated dominance hierarchy of male SI determinants. In Arabidopsis halleri, male dominance hierarchy is reported to have arisen from multiple networks of sRNA target gains and losses. Despite these findings, it remains unknown whether the molecular mechanism underlying the dominance hierarchy is conserved among Brassicaceae. Here, we identified sRNAs and their target sites that can explain the linear dominance hierarchy of Arabidopsis lyrata, a species closely related to A. halleri. We tested the model that we established in Brassica to explain the linear dominance hierarchy in A. lyrata. Our results suggest that the dominance hierarchy of A. lyrata is also controlled by a homology-based interaction between sRNAs and their targets.


Evolution ◽  
2005 ◽  
Vol 59 (7) ◽  
pp. 1437-1448 ◽  
Author(s):  
Barbara K. Mable ◽  
Alexander V. RobertsonSara Dart ◽  
Christina Di Berardo ◽  
Laura Witham

2019 ◽  
Author(s):  
Yan Li ◽  
Mark van Kleunen ◽  
Marc Stift

AbstractAs the first step towards the evolution of selfing from obligate outcrossing, identifying the key mutations underlying the loss of self-incompatibility is of particular interest. However, our current knowledge is primarily based on sequence-based comparisons between selfing species and their self-incompatible relatives, which makes it hard to distinguish causal from secondary mutations. To by-pass this problem, we inferred the genetic basis of the loss of self-incompatibility by intercrossing plants from twelve geographically interspersed outcrossing and selfing populations of North-American Arabidopsis lyrata and determining the breeding system of 1,580 progeny. Self-incompatibility was not restored after crosses between different self-compatible populations. Equal frequencies of self-compatible and self-incompatible progeny emerged from crosses between parents with different breeding systems. We propose a two-locus genetic model for the loss of self-incompatibility in which specific S-locus haplotypes (S1 and S19) are associated with loss of self-incompatibility through their interaction with an unlinked modifier.


2006 ◽  
Vol 88 (1) ◽  
pp. 45-56 ◽  
Author(s):  
AKIRA KAWABE ◽  
BENGT HANSSON ◽  
ALAN FORREST ◽  
JENNY HAGENBLAD ◽  
DEBORAH CHARLESWORTH

We have increased the density of genetic markers on the Arabidopsis lyrata chromosomes AL6 and AL7 corresponding to the A. thaliana chromosome IV, in order to determine chromosome rearrangements between these two species, and to compare recombination fractions across the same intervals. We confirm the two rearrangements previously inferred (a reciprocal translocation and a large inversion, which we infer to be pericentric). By including markers around the centromere regions of A. thaliana chromosomes IV and V, we localize the AL6 centromere, and can localize the breakpoints of these chromosome rearrangements more precisely than previously. One translocation breakpoint was close to the centromere, and the other coincided with one end of the inversion, suggesting that a single event caused both rearrangements. At the resolution of our mapping, apart from these rearrangements, all other markers are in the same order in A. lyrata and A. thaliana. We could thus compare recombination rates in the two species. We found slightly higher values in A. thaliana, and a minimum estimate for regions not close to a centromere in A. lyrata is 4–5 centimorgans per megabase. The mapped region of AL7 includes the self-incompatibility loci (S-loci), and this region has been predicted to have lower recombination than elsewhere in the genome. We mapped 17 markers in a region of 1·23 Mb surrounding these loci, and compared the approximately 600 kb closest to the S-loci with the surrounding region of approximately the same size. There were significantly fewer recombination events in the closer than the more distant region, supporting the above prediction, but showing that the low recombination region is very limited in size.


Evolution ◽  
2010 ◽  
Vol 64 (12) ◽  
pp. 3495-3510 ◽  
Author(s):  
John Paul Foxe ◽  
Marc Stift ◽  
Andrew Tedder ◽  
Annabelle Haudry ◽  
Stephen I. Wright ◽  
...  

2020 ◽  
Author(s):  
Stuart R. Macgregor ◽  
Hyun Kyung Lee ◽  
Hayley Nelles ◽  
Daniel C. Johnson ◽  
Tong Zhang ◽  
...  

AbstractSuccessful reproduction in the Brassicaceae is mediated by a complex series of interactions between the pollen and the pistil, and some species have an additional layer of regulation with the self-incompatibility trait. While the initial activation of the self-incompatibility pathway by the pollen S-locus protein11/S-locus cysteine-rich peptide and the stigma S Receptor Kinase is well characterized, the downstream mechanisms causing self-pollen rejection are still not fully understood. In previous studies, we had detected the presence of autophagic bodies with self-incompatible pollinations in Arabidopsis lyrata and transgenic A. thaliana lines, but it was not known if autophagy was essential for self-pollen rejection. Here, we investigated the requirement of autophagy in this response by crossing mutations in the essential AUTOPHAGY7 (ATG7) gene into two different transgenic self-incompatible A. thaliana lines in the Col-0 and C24 accessions. By using these previously characterized transgenic lines that express A. lyrata and A. halleri self-incompatibility genes, we demonstrated that disrupting autophagy can weaken their self-incompatible responses in the stigma. When the atg7 mutation was present, an increased number of self-incompatible pollen were found to hydrate and form pollen tubes that successfully fertilized the self-incompatible pistils. Additionally, we confirmed the presence of GFP-ATG8a labelled autophagosomes in the stigmatic papillae following self-incompatible pollinations. Together, these findings support the requirement of autophagy in the self-incompatibility response and add to the growing understanding of the cellular events that take place in the stigma to reject self-pollen.One Sentence SummaryIn self-incompatible transgenic Arabidopsis thaliana lines, autophagy is an integral part of the cellular responses in the stigma to efficiently block fertilization by self-incompatible pollen.


Genetics ◽  
2001 ◽  
Vol 158 (1) ◽  
pp. 387-399 ◽  
Author(s):  
Mikkel H Schierup ◽  
Barbara K Mable ◽  
Philip Awadalla ◽  
Deborah Charlesworth

Abstract We study the segregation of variants of a putative self-incompatibility gene in Arabidopsis lyrata. This gene encodes a sequence that is homologous to the protein encoded by the SRK gene involved in self-incompatibility in Brassica species. We show by diallel pollinations of plants in several full-sib families that seven different sequences of the gene in A. lyrata are linked to different S-alleles, and segregation analysis in further sibships shows that four other sequences behave as allelic to these. The family data on incompatibility provide evidence for dominance classes among the S-alleles, as expected for a sporophytic SI system. We observe no division into pollen-dominant and pollen-recessive classes of alleles as has been found in Brassica, but our alleles fall into at least three dominance classes in both pollen and stigma expression. The diversity among sequences of the A. lyrata putative S-alleles is greater than among the published Brassica SRK sequences, and, unlike Brassica, the alleles do not cluster into groups with similar dominance.


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