Vasconcellea cauliflora – a new natural host of cucumber mosaic virus

AbstractVasconcellea cauliflora plants exhibiting chlorotic spots, mottling and mosaic with yellowing on leaves were observed in Pune, India in October 2020. The disease incidence was 16%. The samples were screened for cucumber mosaic virus (CMV), papaya ringspot virus, tobacco mosaic virus and zucchini yellow mosaic virus using ELISA. Sap inoculation on healthy V. cauliflora plants using CMV positive DAS-ELISA samples reproduced field symptoms. The transmission upon mechanical inoculation was 100%. For further confirmation, RT-PCR was carried out using CMV coat protein gene specific primers. Amplicons of expected size (c. 650 bp) were obtained in all symptomatic and sap inoculated samples. No amplification was observed in the asymptomatic samples. BLASTn analysis revealed that the amplicon sequence shares more than 99% identity with CMV isolates and in phylogenetic analysis it clustered with CMV IB isolates. This is the first record of V. cauliflora as a natural host of CMV worldwide.Keywords: Highland papayaDAS-ELISART-PCRVasconcellea caulifloraCMVIndia AcknowledgementsThe authors thank the Director, ICAR – IARI, New Delhi and Head, ICAR-IARI, Regional Station, Pune for providing lab facilities.Authors’ contributionsRV and ST carried out sample collection. RV and SSK carried out mechanical inoculation. SSK performed DAS-ELISA. AV performed RNA extraction and two step RT-PCR assay. ST and AV submitted the sequence to GenBank and carried out phylogenetic analysis. RV, ST and AV prepared the manuscript.Disclosure statementThe authors have no conflicts of interest.