Mixed infection of phytoplasma and begomovirus associated with leaf curling and witches’ broom disease of Zinnia elegans in India

Abstract

Zinnia elegans belonging to the asteraceae family is a flowering annual summer plant and is native to Mexico. Symptoms of excessive leaf curling, little leaf, stunting and witches’ broom were observed on Z. elegans in Tripura state of India during 2016–2017. PCR assays using phytoplasma universal primer pairs P1/P7 and R16F2n/R16R2 and tomato leaf curl virus coat protein specific primers yielded specific amplifications of ~ 1.25 kbp and ~ 800 bp, respectively from the symptomatic zinnia leaf samples. Sequence comparison, phylogenetic and virtual RFLP analysis of 16S rRNA gene sequences of zinnia isolate confirmed the presence of ‘Candidatus Phytoplasma asteris’ (16SrI-B subgroup). Further coat protein sequence comparison and phylogenetic tree analysis of coat protein gene confirmed association of begomovirus with zinnia symptomatic samples and identified it as a strain of tomato leaf curl virus. Our results confirmed a mixed infection of ‘Ca. P. asteris’ and begomovirus with zinnia leaf curl and witches’ broom symptoms.