S-RNase gene of Nicotiana alata is expressed in developing pollen.
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.
Dodds
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PN
Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Parkville, Victoria, Australia.
Bönig
I
I
Du
H
H
Rödin
J
J
Anderson
M A
MA
Newbigin
E
E
Clarke
A E
AE
D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D017343:Genes, Plant; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D010947:Plants, Toxic; D011058:Pollen / Q000201:enzymology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D012260:Ribonucleases / Q000235:genetics*; D014026:Nicotiana / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D014158:Transcription, Genetic
D018076:DNA, Complementary; D012333:RNA, Messenger; D012260:Ribonucleases