Archivio Journal of Plant Pathology

Abstract:

Codiaeum variegatum (garden-grown croton species), a member of the family Euphorbiaceae. is native to southern India, Sri Lanka, Indonesia, Malaysia, and the western Pacific Ocean islands, where it grows in open forests and scrub. In August 2013, leaf yellows and witches' brooms symptoms were observed on C. variegatum plants grown at Lucknow (Uttar Pradesh, India) and Sitamadhi (Bihar, India). Three symptomatic samples from each locations were tested for phytoplasma detection using the universal primer P1/P7 (Deng and Hiruki, 1991;Schneider et al., 1995) in a first round, then primers R16F2n/R16R2 in nested PCR assays (Gundersen and Lee, 1996). Products of ca. 1.8 kb and 1.2 kb, respectively, were amplified from all symptomatic samples. Six amplicons of ca. 1.2 kb were directly sequenced from both the ends and found 99% identical to each others. One representative 16Sr DNA C. variegatum phytoplasma sequence form each location was deposited in GenBank under the accession Nos KJ161308 (Lucknow) and KJ161309 (Sitamadhi). Both tphytoplasma isolates shared maximum 16S rDNA sequence identity (99%) among themselves and with several isolates of Candidatus Phytoplasma asteris (16SrI group) from different parts of the world. Results of phylogenetic analyses of 1.25 kb 16Sr DNA products from Lucknow and Sitamadhi isolates revealed that the Lucknow isolate clustered together with strains of 16SrI-D subgroup, whereas the Sitamadhi isolate clustered with 16Sr I-B member strains of reference isolates in GenBank. Candidatus Phytoplasma asteris has been associated with diseased Croton spp. from Colombia (Perilla et al., 2012; HG764351) but, to the best of our knowledge it has never been reported from India.