Vasconcellea cauliflora – a new natural host of cucumber mosaic virus

Abstract

Vasconcellea 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.