Transcriptional insights of citrus defense response against Diaporthe citri.

Citrus melanose, caused by Diaporthe citri, is one of the most important and widespread fungal diseases of citrus. Previous studies demonstrated that the citrus host was able to trigger the defense response to restrict the spread of D. citri. However, the molecular mechanism underlying this defense response has yet to be elucidated. Here, we used RNA-Seq to explore the gene expression pattern at the early (3 days post infection, dpi) and late (14 dpi) infection stages of citrus leaves in response to D. citri infection, and outlined the differences in transcriptional regulation associated with defense responses. The functional enrichment analysis indicated that the plant cell wall biogenesis was significantly induced at the early infection stage, while the callose deposition response was more active at the late infection stage. CYP83B1 genes of the cytochrome P450 family were extensively induced in the callus deposition-mediated defense response. Remarkably, the gene encoding pectin methylesterase showed the highest upregulation and was only found to be differentially expressed at the late infection stage. Genes involved in the synthesis and regulation of phytoalexin coumarin were effectively activated. F6'H1 and S8H, encoding key enzymes in the biosynthesis of coumarins and their derivatives, were more strongly expressed at the late infection stage than at the early infection stage. Collectively, our study profiled the response pattern of citrus leaves against D. citri infection and provided the transcriptional evidence to support the defense mechanism.

The Genome Sequence of the Citrus Melanose Pathogen Diaporthe citri and Two Citrus-Related Diaporthe Species.

Melanose disease is one the most widely distributed and economically important fungal diseases of citrus worldwide. The causative agent is the filamentous fungus Diaporthe citri (syn. Phomopsis citri). Here, we report the genome assemblies of three strains of D. citri, namely strains ZJUD2, ZJUD14, and Q7, which were generated using a combination of PacBio Sequel long-read and Illumina paired-end sequencing data. The assembled genomes of D. citri ranged from 52.06 to 63.61 Mb in genome size, containing 15,977 to 16,622 protein-coding genes. We also sequenced and annotated the genome sequences of two citrus-related Diaporthe species, D. citriasiana and D. citrichinensis. In addition, a database for citrus-related Diaporthe genomes was established to provide a public platform to access genome sequences, genome annotation and comparative genomics data of these Diaporthe species. The described genome sequences and the citrus-related Diaporthe genomes database provide a useful resource for the study of fungal biology, pathogen-host interaction, molecular diagnostic marker development, and population genomic analyses of Diaporthe species. The database will be updated regularly when the genomes of newly isolated Diaporthe species are sequenced. The citrus-related Diaporthe genomes database is freely available for nonprofit use at zjudata.com/blast/diaporthe.php.

Nigrospora oryzae Causing Leaf Spot Disease on Chrysanthemum × morifolium Ramat and Screening of Its Potential Antagonistic Bacteria.

Chrysanthemum × morifolium Ramat. is a famous perennial herb with medicinal, edible, and ornamental purposes, but the occurrence of plant diseases can reduce its value. A serious disease that caused leaf spots in C. morifolium appeared in 2022 in Tongxiang City, Zhejiang Province, China. The C. morifolium leaves with brown spots were collected and used for pathogen isolation. By completing Koch's postulates, it was proven that the isolate had pathogenicity to infect C. morifolium. It was determined that the pathogen isolated from chrysanthemum leaves was Nigrospora oryzae, through morphology and a multilocus sequence analysis method using a combination of the internal transcribed spacer gene (ITS), beta-tubulin gene (TUB2), and translation elongation factor 1-alpha gene (TEF1-α). This is the first report of C. morifolium disease caused by N. oryzae in the world. Through dual culture assay on PDA plates, 12 strains of bacteria with antagonistic effects were selected from 231 strains from the C. morifolium phyllosphere, among which Bacillus siamensis D65 had the best inhibitory effect on N. oryzae growth. In addition, the components of a strain D65 fermentation broth were profiled by SPME-GC-Q-TOF analysis, providing a foundation for further application and research of biological control.

[Therapeutic mechanism of bleomycin A5 on infancy hemangioma: an experimental study].

OBJECTIVE: To investigate the therapeutic mechanism of Bleomycin A5 on infancy hemangioma. METHODS: After intralesional injection of Bleomycin A5 into the tumor of animal model of infancy hemangioma, the variation of tumor form was and the variation of tumor structure were observed using light microscope and electron microscope, the variation of tumor gene expression spectra was also tested by DNA microarray technique. RESULTS: After treatment, the tumor gradually shrunk, hardened, disappeared one month later. The tumor lost appearance of infancy hemangioma and replaced by lamellar collagen fibers and cellular nucleus scattered in the fibers, and almost all cells were necrotic and dissolved. Under electron microscope, only large stretches of dissolved cell could be seen without intact cells and blood vessels, but apoptotic cells and bodies could also be found. The results of DNA microarray analysis showed that 9 genes associated with apoptosis (murine double minute 2, heat-labile enterotoxin B subunit, lymphotoxin B receptor, tumor necrosis factor ligand superfamily 7, tumor necrosis factor receptor superfamily 21, tumor necrosis factor receptor superfamily 1A, myeloid cell leukemia-1, caspase3), 13 genes associated with cell proliferation and cell cycle (cell division cycle27, cell division cycle37, CDC28 protein kinase 1B, cycling B1, cullin 2, cullin 3, cullin 4A, growth arrest and DNA damage-inducible 45A, meiotic recombination 11 homolog B, forkhead box M1, minichromosome maintenance 7, antigen identified by monoclonal antibody ki 67, proliferating cell nuclear antigen), and 11 genes associated with cellular stress and toxic reaction (glutathione peroxidase 1, metallothioneins, superoxide dismutase-1, heat shock protein A1A, heat shock protein A2, heat shock protein A4, heat shock protein A5, heat shock protein 9B, heat shock protein CA, macrophage migration inhibitory factor, plasminogen activator inhibitor)were up or down regulated more than 2 folds in tumors treated with Bleomycin A5 compared with controls. CONCLUSIONS: The therapeutic effect of Bleomycin A5 on infancy hemangioma is the synthetic results of multiple factors. Bleomycin A5 could not only induce apoptosis and inhibit cell proliferation, but also depressed the ability of cell stress and toxic reaction.

[Effect of bleomycin A5 on the hemangioma-derived endothelial cell line XTPS-1].

OBJECTIVE: To investigate the effect of bleomycin A5 on the hemangioma-derived endothelial cell line XTPS-1. METHODS: Hemangioma-derived endothelial cell line XTPS-1 was cultured with different concentration of bleomycin A5 (1000, 100, 10, 1, 0 mg/L), and then the survival rate was measured by methyl thiazolyl terazolium (MTT), the variation of cell morphology was observed using inverted phase contrast microscope and electron microscope, the variation of cell cycle and apoptosis rate were measured using flow cytometry. RESULTS: After 24 hours culture the cell survival rate was (92.96 ± 3.66)% and (99.86 ± 0.12)% in lower saturation group (10 and 1 mg/L), but (34.08 ± 3.11)% and (43.28 ± 2.88)% in higher saturation group (1000 and 100 mg/L). The difference between them was more significant (P < 0.01). Lower saturation of bleomycin A5 (10 and 1 mg/L)could induce apoptosis but had almost no cytotoxic effect. Higher saturation of bleomycin A5 (1000 and 100 mg/L) not only induced apoptosis, but also had strong cytotoxic effect, which was concentration dependent. CONCLUSIONS: bleomycin A5 could induce apoptosis, inhibit cell proliferation and has direct cytotoxic effect.

[Establishment of human infancy hemangioma-derived endothelial cell line XPTS-1 and animal model of human infancy hemangioma].

OBJECTIVE: To establish an immortalized human infancy hemangioma-derived endothelial cell line (HemEC) and animal model of human infancy hemangioma. METHODS: Hemangioma-derived endothelial cells from specimen of human infancy hemangioma were cultured in vitro and monocloed, and then its growth curve was made, karyomorphism of chromosome analyzed, morphologic characteristics observe, factor VIII related antigen identified by immunohistochemical method.Vascular endothelial growth factor receptor 2 (VEGFR-2) was detected by flow cytometry. HemEC were inoculated subcutaneously in athymic mouse to establish animal model of infancy hemangioma. The animal model was observed closely and its pathological characteristic was also studied. RESULTS: The cultural cells grew active, and immortalized spontaneously when they were subcultured on sixteenth generation. This cell line was cultivated for more than 70 times within one year and in good condition after freezing and resuscitating once and again, and had the morphologic character of HemEC. The cell population doubling time was 22 h. Factor VIII and VEGFR-2 were expressed positively. Karyo type analysis of the cell line showed abnormal diploid with the modal chromosomal number varying between diploid and triploid. The cell line was then named XPTS-1. The animal model of infancy hemangioma was successfully established and its character of histopathology was similar with that of infancy hemangioma. CONCLUSIONS: The cell line of HemEC was successfully established and immortalized spontaneously, and had the morphologic and biological character of HemEC. The animal model of infancy hemangioma was successfully established and showed the character of histopathology similar with that of infancy hemangioma.