Internuclear gene silencing in Phytophthora infestans.
Transformation of the diploid oomycete plant pathogen Phytophthora infestans with antisense, sense, and promoter-less constructs of the coding sequence of the elicitin gene inf1 resulted in transcriptional silencing of both the transgenes and the endogenous gene. Since heterokaryons obtained by somatic fusion of an inf1-silenced transgenic strain and a wild-type strain displayed stable gene silencing, inf1 silencing is dominant and acts in trans. Inf1 remained silenced in nontransgenic homokaryotic progeny from the silenced heterokaryons, thereby demonstrating that the presence of transgenes is not essential for maintaining the silenced status of the endogenous inf1 gene. These findings support a model reminiscent of paramutation and involving a trans-acting factor that is capable of transferring a silencing signal between nuclei.
van West
P
P
Laboratory of Phytopathology, Wageningen Agricultural University Graduate School of Experimental Plant Sciences, The Netherlands. p.vanwest@abdn.ac.uk
Kamoun
S
S
van 't Klooster
J W
JW
Govers
F
F
D020418:Algal Proteins; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016375:Antisense Elements (Genetics) / Q000235:genetics; D015139:Blotting, Southern; D002459:Cell Fusion / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism; D017077:Culture Media, Conditioned; D019175:DNA Methylation; D004252:DNA Mutational Analysis; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D018628:Gene Dosage; D005786:Gene Expression Regulation; D010838:Phytophthora / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010944:Plants / Q000382:microbiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011506:Proteins; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism; D017384:Sequence Deletion / Q000235:genetics; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014170:Transformation, Genetic; D019076:Transgenes / Q000235:genetics
D020418:Algal Proteins; D000900:Anti-Bacterial Agents; D016375:Antisense Elements (Genetics); D017077:Culture Media, Conditioned; D005656:Fungal Proteins; D011506:Proteins; D012333:RNA, Messenger; D015534:Trans-Activators; C085101:elicitin, Phytophthora