Development and pathogenicity analysis of full-length infectious cDNA clones of citrus yellow mottle-associated virus in citrus plants

Citrus yellow mottle-associated virus(CiYMaV)belonging to the subgenus Mandarivirus within the genus Potexvirus,was first identified in 2018 from Pakistan(CiYMaV-PK),where it is endemic in several regions.Here,three full-length cDNA clones(pCiYMaV-FL-1,pCiYMaV-FL-18,and pCiYMaV-FL-22)corresponding to the genomic RNA of CiYMaV were constructed and then agroinfiltrated on Chandler pummelo(Citrus grandis)seedlings using the vacuum infiltration method.All the inoculated plants developed severe vein yellowing,leaf mottling,and dwarfing symptoms by 40 days post-infiltration(dpi).The results of a direct tissue blot immunoassay and reverse transcription polymerase chain reaction detection showed 94.7–100%infection rates of pCiYMaV-FL at 60 dpi.Despite there being no observed difference among the three clones in the severity of symptom,pCiYMaV-FL-22 showed the highest accumulation levels of viral RNA and coat proteins.Moreover,pCiYMaV-FL-22 successfully infected seven other citrus varieties and induced symptoms in five of them.Transmission electron microscopy identified the presence of filamentous virus particles in extracts from systemic leaves of the plants infected with pCiYMaV-FL-22 at 6-months post-infiltration.Taken together,the results indicate that Koch's postulates were fulfilled for CiYMaV in citrus plants.This is the first report of full-length infectious cDNA clones of CiYMaV,and thus,the data provide a basis for further study of the molecular mechanisms of virus infection and the development of a viral vector to express foreign genes in citrus plants.

Prognostic significance of epidermal growth factor-like domain 7 in pancreatic cancer

BACKGROUND： Recent studies have shown the clinical significance of epidermal growth factor-like domain 7（EGFL7）in a variety of cancers. However, the relationship between EGFL7 and the prognosis of pancreatic cancer（PC） remains unclear. The present study was undertaken to investigate the role of EGFL7 in the prognosis of PC.METHODS： The expression of EGFL7 in nine PC cell lines was first determined by Western blotting analysis. Tissue microarray-based immunohistochemical staining was performed in paired formalin-fixed paraffin-embedded tumor and non-tumor samples from 83 patients with PC. Finally,correlations between EGFL7 expression and clinicopathological variables as well as overall survival were evaluated.RESULTS： EGFL7 was widely expressed in all PC cell lines tested.EGFL7 expression in tumor tissues was significantly higher than that in non-tumor tissues（P0.040）. In addition, univariate analysis revealed that high EGFL7 expression in tumor tissues was significantly associated with poor overall survival,accompanied by several conventional clinicopathological variables, such as gender, histological grade and lymph node metastasis. In a multivariate Cox regression test, EGFL7 expression was identified as an independent marker for longterm outcome of PC.CONCLUSION： Our data showed that EGFL7 is extensively expressed in PC and that EGFL7 is associated with poor prognosis.