Kakizaki Tomohiro, Takada Yoshinobu, Ito Akiko, Suzuki Go, Shiba Hiroshi, Takayama Seiji, Isogai Akira, Watanabe Masao
Faculty of Agriculture, Iwate University, Morioka, 020-8550 Japan.
Plant Cell Physiol. 2003 Jan;44(1):70-5. doi: 10.1093/pcp/pcg009.
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.
自交不亲和性（SI）通过排斥来自具有相同S表型的植物的花粉来防止自花受精。芸苔属的SI系统由单个位点S上的多个等位基因进行孢子体控制，并且在柱头和花粉中都观察到S单倍型之间的显性关系。我们之前已经在白菜型油菜中鉴定出五种不同的II类S单倍型。在这里，我们对其中四种II类S单倍型的S杂合子与其各自的亲本S纯合子进行了测交，并在花粉方面观察到了线性显性关系。为了确定这种关系是如何被控制的，我们使用相应的SP11克隆作为探针，对六个S杂合子及其各自的亲本S纯合子进行了RNA凝胶印迹分析。在所有六个S杂合子中，来自显性单倍型的SP11被大量表达，而来自隐性单倍型的SP11则受到抑制。因此，花粉方面SI表型的线性显性关系是由SP11的表达调控的。
