Originally published as Genetics Published Articles Ahead of Print on January 21, 2007.
Genetics, Vol. 175, 1965-1973, April 2007, Copyright © 2007
doi:10.1534/genetics.106.069393
Epigenetic Mechanisms for Breakdown of Self-Incompatibility in Interspecific Hybrids
June B. Nasrallah*,1,
Pei Liu*,
Susan Sherman-Broyles*,
Renate Schmidt
and
Mikhail E. Nasrallah*
* Department of Plant Biology, Cornell University, Ithaca, New York 14853 and
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466 Gatersleben, Germany
1 Corresponding author: Department of Plant Biology, 228 Plant Science Bldg., Cornell University, Ithaca, NY 14853.
E-mail: jbn2{at}cornell.edu
As a major agent of rapid speciation, interspecific hybridization has played an important role in plant evolution. When hybridization involves species that exhibit self-incompatibility (SI), this prezygotic barrier to self-fertilization must be overcome or lost to allow selfing. How SI, a normally dominant trait, is lost in nascent hybrids is not known, however. Here we demonstrate that hybrid self-fertility can result from epigenetic changes in expression of the S-locus genes that determine specificity in the SI response. We analyzed loss of SI in synthetic hybrids produced by crossing self-fertile and self-incompatible species in each of two crucifer genera. We show that SI is lost in the stigmas of A. thalianalyrata hybrids and their neo-allotetraploid derivatives and in the pollen of C. rubellagrandiflora hybrids and their homoploid progenies. Aberrant processing of S-locus receptor kinase gene transcripts as detected in Arabidopsis hybrids and suppression of the S-locus cysteine-rich protein gene as observed in Capsella hybrids are two reversible mechanisms by which SI might break down upon interspecific hybridization to generate self-fertile hybrids in nature.
Related articles in Genetics:
- ISSUE HIGHLIGHTS
Genetics 2007 175: 0.
[Full Text]
Copyright © 2007 by the Genetics Society of America.