Molecular identification of phytoplasmas associated with little leaf disease of brinjal in Andhra Pradesh and Telangana states of India

Abstract

Brinjal little leaf (BLL) is a very important phytoplasma disease in India that causes severe economic losses every year. During 2020, symptoms of little leaf and witches’ broom were observed in brinjal plants grown in the farmer fields at Kadapa, Andhra Pradesh and Mahabubnagar district, Telangana states. Four symptomatic and two symptomless plants collected from the surveyed places of both states were subjected to DNA extraction and used as template in nested PCR assays with universal phytoplasma 16S rRNA primers. Amplification of about 1.25 kb product with primers R16F2n/R2 was obtained only from symptomatic BLL plants and the positive control, but not from asymptomatic plants. Pair wise sequence comparison and phylogenetic analyses of 16S rRNA gene sequences of these phytoplasma strains confirmed that the phytoplasmas from Mahabubnagar district in Telangana were ‘Candidatus Phytoplasma trifolii’-related strains, while those from Kadapa, Andhra Pradesh, were related to Ca. P australasia’. Further virtual RFLP analysis of 16S rDNA sequences allowed the classification of these strains into 16SrVI-D and 16SrII-D subgroups, respectively.