Dodds P N, Bönig I, Du H, Rödin J, Anderson M A, Newbigin E, Clarke A E
Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Parkville, Victoria, Australia.
Plant Cell. 1993 Dec;5(12):1771-82. doi: 10.1105/tpc.5.12.1771.
In the solanaceous plant Nicotiana alata, self-incompatibility is controlled by a single, multiallelic locus (S locus) expressed in both pollen and pistil. Previously, we have shown cosegregation between alleles of the S locus and alleles of a gene that encodes a glycoprotein with ribonuclease activity (S-RNase). Furthermore, expression of the S-RNase gene is apparently confined to the pistil and is correlated with the onset of self-incompatibility. In this paper, we report that the S-RNase gene is also expressed at low levels in developing pollen. A transcript in developing pollen hybridized to a cDNA encoding the S2-RNase allele of the parent plant and did not hybridize to cDNAs encoding other S-RNase alleles. Two cDNAs for the S2-RNase were cloned from a library derived from anthers of a plant homozygous for the S2 allele and both corresponded to the coding sequence of the S2-RNase. The product of the S-RNase gene was detected by immunocytochemistry in the intine of mature, hydrated pollen grains. These results are interpreted in the light of current knowledge of the structure of the S locus.
在茄科植物烟草中，自交不亲和性由一个单一的多等位基因位点（S位点）控制，该位点在花粉和雌蕊中均有表达。此前，我们已经证明S位点的等位基因与一个编码具有核糖核酸酶活性糖蛋白的基因（S-RNase）的等位基因之间存在共分离现象。此外，S-RNase基因的表达显然局限于雌蕊，并且与自交不亲和性的开始相关。在本文中，我们报道S-RNase基因在发育中的花粉中也有低水平表达。发育中的花粉中的一种转录本与编码亲本植物S2-RNase等位基因的cDNA杂交，而不与编码其他S-RNase等位基因的cDNA杂交。从一个对于S2等位基因纯合的植物的花药文库中克隆出了两个S2-RNase的cDNA，二者均与S2-RNase的编码序列相对应。通过免疫细胞化学方法在成熟的、水合的花粉粒的内壁中检测到了S-RNase基因的产物。根据目前对S位点结构的了解对这些结果进行了解释。
