Genome Sequence of a New Carnation Small Viroid-Like RNA, CarSV-1

Area of Science:

• Plant virology
• RNA genomics
• Molecular biology

Background:

• Viroid-like RNAs are small, circular, non-protein-coding RNA molecules that replicate independently in host plants.
• Carnations (Dianthus caryophyllus) are economically important ornamental plants susceptible to various viral and viroid-like pathogens.
• Previous research has identified Carnation Spanish Satellite Virus (CarSV), a well-studied viroid-like RNA in carnations.

Purpose of the Study:

• To report the genome sequence of a newly identified circular viroid-like RNA from carnation leaves.
• To characterize the genomic features of this new RNA and compare it to known viroid-like RNAs.
• To investigate its potential co-occurrence with other carnation viruses.

Main Methods:

• Genome sequencing of the isolated RNA from infected carnation leaves.
• Bioinformatic analysis to determine genome structure, size, and sequence similarity.
• Comparative genomics to assess relatedness to known viroid-like RNAs, including CarSV.
• Co-infection analysis with other known carnation viruses.

Main Results:

• A novel circular viroid-like RNA, designated CarSV-1, was identified and its complete genome sequence determined.
• CarSV-1 exhibits 62% sequence similarity to the previously characterized CarSV.
• The CarSV-1 genome contains complete hammerhead consensus sequences, indicative of self-cleavage activity.
• CarSV-1 was found to co-occur with known carnation viruses, such as Carnation Mottle Virus (CarMV).

Conclusions:

• A new viroid-like RNA, CarSV-1, has been discovered in carnations, expanding the known viroid-like RNA diversity in this host.
• The genomic characteristics of CarSV-1 suggest a functional hammerhead ribozyme essential for its replication cycle.
• The co-occurrence of CarSV-1 with other carnation viruses highlights the complex viral landscape affecting carnation health and productivity.