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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Crop Diseases, Pests and Genetics Research » Research » Publications at this Location » Publication #410315
Research Project: Identifying Vulnerabilities in Vector-host-pathogen Interactions of Grapevine and Citrus Pathosystems to Advance Sustainable Management Strategies

Location: Crop Diseases, Pests and Genetics Research

Title: Research update on Citrus yellow vein clearing virus in California

Author
item Sun, Yongduo
item Yokomi, Raymond

Submitted to: Citrograph
Publication Type: Trade Journal
Publication Acceptance Date: 12/4/2023
Publication Date: 3/4/2024
Citation: Sun, Y., Yokomi, R.K. 2024. Research update on Citrus yellow vein clearing virus in California. Citrograph. 15(2):30-33.

Interpretive Summary: Citrus yellow vein clearing virus (CYVCV) is a newly introduced citrus virus that was detected in urban citrus trees in the City of Tulare, California in 2022. The research objective of our project are to characterize this strain CYVCV and determine its mode of transmission. CYVCV was graft inoculated to a citrus host range and all cultivars were successfully infected and supported virus replication. CYVCV was highly symptomatic in lemons and sour oranges but remained asymptomatic in the other cultivars tested. The full-length genome of the California strain of CYVCV was sequenced and compared to other full-length and coat protein gene sequences from a worldwide genome database. Genomic analysis showed that California CYVCV isolates formed a unique group apart from the other isolates and shared a common ancestry with Indian CYVCV isolates. The spirea and cotton aphid both transmitted CYVCV and vector tests with the citrus whitefly are underway. An infectious clone of CYVCV CA1 was developed as a tool to accelerate our research on CYVCV.

Technical Abstract: Citrus yellow vein clearing virus (CYVCV) is an invasive citrus pathogen detected in the U.S. for the first time in California in 2022. Spread of the exotic CYVCV to commercial citrus orchards is a threat to California’s citrus industry, as it has been associated with a 20-80% loss of lemon production in areas of China. Infection with CYVCV was reported in urban citrus trees in the city of Tulare. This update describes research aiming to characterize CYVCV and determine its origin and mode of transmission in California. CYVCV was graft inoculated to different citrus plants. All cultivars were successfully infected and supported virus replication. Of the cultivars tested, signs of CYVCV infection were observed in lemons and sour oranges. The genetic blueprint, or genome, of the California strain of CYVCV (CYVCV CA1) was obtained and compared to other genetic data from a worldwide database. Genomic analysis showed that CYVCV from California formed a unique group apart from other isolates and shared a common ancestry with CYVCV isolates from India. The spirea and cotton aphids transmitted CYVCV CA1 to susceptible citrus plants. Similar transmission studies are underway with the citrus whitefly. Our research was accelerated by the creation of a CYVCV CA1 variant that allows detailed studies to understand how this emerging virus infects citrus plants in the U.S.