Blue-White Colony Selection of Virus-Infected Isogenic Recipients Based on a Chrysovirus Isolated from Penicillium italicum
Mycoviruses have been found to infect more than 12 species of Penicillium, but have not been isolated from Penicillium italicum (P. italicum). In this study, we isolated and characterized a new double-stranded RNA (dsRNA) virus, designated Penicillium italicum chrysovirus 1 (PiCV1), from the citrus pathogen P. italicum HSPi-YN1. Viral genome sequencing and molecular characterization indicated that PiCV1 was highly homologous to the previously described Penicillium chrysogenum virus. We further constructed the mutant HSPi-YN1ΔpksP defective in the polyketide synthase gene (pksP), which is involved in pigment biosynthesis, and these mutants formed albino (white) colonies. Then we applied hyphal anastomosis method to horizontally transmit PiCV1 from the white virus-donors (i.e., HSPi-YN1 mutants) to wild-type recipients (i.e., P. italicum strains HSPi-CQ54, HSPi-HB4, and HSPi-HN1), and the desirable PiCV1-infected isogenic recipients, a certain part of blue wild-type strains, can be eventually selected and confirmed by viral genomic dsRNA profile analysis. This blue-white colony screening would be an easier method to select virus-infected P. italicum recipients, according to distinguishable color phenotypes between blue virus-recipients and white virus-donors. In summary, the current work newly isolated and characterized PiCV1, verified its horizontal transmission among dually cultured P. italicum isolates, and based on these, established an effective and simplified approach to screen PiCV1-infected isogenic recipients.
KeywordsPenicillium italicum chrysovirus 1 (PiCV1) pksP knockout White-blue colony screening Isogenic recipients Horizontal transmission
This work was supported by the National Natural Science Foundations of China (No. 31371893), the Natural Science Fund of Hubei Province (No. 2018CFB676) and the Project of Hubei Key Laboratory of Genetic Regulation and Integrative Biology (Grant No. GRIB20184).
DL and YY conceived this study, acquired project funding, revised to complete final version of manuscript, and supervised all research activities. TZ and NL designed experiments and completed the data analysis. QC, YC, BT and GL performed most of the experiments. TZ wrote the paper draft. All authors read and approved the final manuscript.
Compliance with Ethics Standards
Conflict of interest
The authors declare that they have no competing interests.
Animal and Human Rights Statement
This article does not contain any studies with human or animal subjects performed by any of the authors.
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