A cluster of NIF transcriptional regulators with divergent patterns of spore-specific expression in Phytophthora infestans.
Seven genes encoding putative nuclear LIM interactor-interacting factors (NIFs) from Phytophthora infestans were characterized. Four exhibited spore-specific expression and clustered within 20kb, and three hyphal forms were also identified. Pi-nifS mRNA accumulated during sporulation, and Pi-nifC1, Pi-nifC2, and Pi-nifC3 mRNA during zoosporogenesis. By expressing fusions with the beta-glucuronidase reporter gene in transformants, promoter fragments determining patterns of transcription specific to sporangia formation or zoosporogenesis were identified. Such studies also indicated that Pi-nifS was expressed at a late stage of sporulation. Pi-nifC1, Pi-nifC2, and Pi-nifC3 induction involved inositol-trisphosphate signaling based on studies with 2-aminoethoxydiphenylborate and U-73122, was independent of verapamil-sensitive signals, and required the same cool temperatures that trigger zoosporogenesis. In contrast, warmer temperatures favoring direct sporangial germination caused Pi-nifS mRNA to rapidly decay, while verapamil increased mRNA levels. The divergent expression and clustering of the spore-specific genes may help reveal how genomes and developmental pathways evolved within the genus.
Tani
Shuji
S
Department of Plant Pathology, University of California, Riverside, CA 92521, USA.
Kim
Kyoung Su
KS
Judelson
Howard S
HS
D000595:Amino Acid Sequence; D000818:Animals; D004271:DNA, Fungal / Q000737:chemistry / Q000302:isolation & purification; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005966:Glucuronidase / Q000235:genetics; D025301:Hyphae / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D010838:Phytophthora / Q000235:genetics* / Q000502:physiology; D012331:RNA, Fungal / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013172:Spores, Fungal / Q000235:genetics* / Q000502:physiology; D014158:Transcription, Genetic
D004271:DNA, Fungal; D012331:RNA, Fungal; D012333:RNA, Messenger; D005966:Glucuronidase