The S receptor kinase determines self-incompatibility in Brassica stigma.
The self-incompatibility possessed by Brassica is an intraspecific reproductive barrier by which the stigma rejects self-pollen but accepts non-self-pollen for fertilization. The molecular/biochemical bases of recognition and rejection have been intensively studied. Self-incompatibility in Brassica is sporophytically controlled by the polymorphic S locus. Two tightly linked polymorphic genes at the S locus, S receptor kinase gene (SRK) and S locus glycoprotein gene (SLG), are specifically expressed in the papillar cells of the stigma, and analyses of self-compatible lines of Brassica have suggested that together they control stigma function in self-incompatibility interactions. Here we show, by transforming self-incompatible plants of Brassica rapa with an SRK28 and an SLG28 transgene separately, that expression of SRK28 alone, but not SLG28 alone, conferred the ability to reject self (S28)-pollen on the transgenic plants. We also show that the ability of SRK28 to reject S28 pollen was enhanced by SLG28. We conclude that SRK alone determines S haplotype specificity of the stigma, and that SLG acts to promote a full manifestation of the self-incompatibility response.
Takasaki
T
T
Research Institute of Seed Production Co., Ltd., Sendai, Japan. taka@kobe-u.ac.jp
Hatakeyama
K
K
Suzuki
G
G
Watanabe
M
M
Isogai
A
A
Hinata
K
K
D001937:Brassica / Q000201:enzymology / Q000502:physiology*; D006023:Glycoproteins / Q000235:genetics / Q000502:physiology; D006239:Haplotypes; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology; D018514:Plant Structures / Q000502:physiology; D030821:Plants, Genetically Modified; D011058:Pollen / Q000502:physiology; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D012098:Reproduction
D006023:Glycoproteins; D010940:Plant Proteins; C064156:self-incompatibility locus specific glycoprotein, Brassica; D011494:Protein Kinases; C079832:S-receptor kinase