Linear dominance relationship among four class-II S haplotypes in pollen is determined by the expression of SP11 in Brassica self-incompatibility.
Self-incompatibility (SI) prevents self-fertilization by rejecting pollen from plants with the same S phenotype. The Brassica SI system is controlled sporophytically by multiple alleles at the single locus, S, and dominance relationships among S haplotypes are observed in both stigma and pollen. We have identified previously five different class-II S haplotypes in Brassica campestris. Here, we performed test-crosses between S heterozygotes and their respective parental S homozygotes for four of these class-II S haplotypes, and observed a linear dominance relationship on the pollen side. To determine how this relationship is controlled, we performed RNA gel blot analyses for six S heterozygotes and their respective parental S homozygotes using the corresponding SP11 clone as a probe. In all six S heterozygotes, SP11 derived from a dominant haplotype was predominantly expressed, and SP11 derived from a recessive haplotype was repressed. Thus, the linear dominance relationship of the SI phenotype on the pollen side is regulated by the expression of SP11.
Kakizaki
Tomohiro
T
Faculty of Agriculture, Iwate University, Morioka, 020-8550 Japan.
Takada
Yoshinobu
Y
Ito
Akiko
A
Suzuki
Go
G
Shiba
Hiroshi
H
Takayama
Seiji
S
Isogai
Akira
A
Watanabe
Masao
M
D001937:Brassica / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D005298:Fertility / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005799:Genes, Dominant / Q000235:genetics; D006239:Haplotypes / Q000235:genetics*; D006579:Heterozygote; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011058:Pollen / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D010940:Plant Proteins; C431526:SP11 protein, Brassica