First Report of ‘Candidatus Phytoplasma trifolii’ Associated with Witches’ Broom Disease of Rauwolfia serpentina from Northeast Region of India

Abstract

HomePlant DiseaseVol. 103, No. 7First Report of ‘Candidatus Phytoplasma trifolii’ Associated with Witches’ Broom Disease of Rauwolfia serpentina from Northeast Region of India PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of ‘Candidatus Phytoplasma trifolii’ Associated with Witches’ Broom Disease of Rauwolfia serpentina from Northeast Region of IndiaM. K. Kalita, G. P. Rao, Madhupriya, and A. K. GogoiM. K. KalitaBiswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali, Assam 784176, IndiaSearch for more papers by this author, G. P. Rao†Corresponding author: G. P. Rao; E-mail Address: gprao_gor@rediffmail.comhttp://orcid.org/0000-0003-1057-7826Division of Plant Pathology, ICAR–Indian Agricultural Research Institute, Pusa Campus, New Delhi 110 012, IndiaSearch for more papers by this author, MadhupriyaDivision of Plant Pathology, ICAR–Indian Agricultural Research Institute, Pusa Campus, New Delhi 110 012, IndiaSearch for more papers by this author, and A. K. GogoiBiswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali, Assam 784176, IndiaSearch for more papers by this authorAffiliationsAuthors and Affiliations M. K. Kalita1 G. P. Rao2 † Madhupriya2 A. K. Gogoi1 1Biswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali, Assam 784176, India 2Division of Plant Pathology, ICAR–Indian Agricultural Research Institute, Pusa Campus, New Delhi 110 012, India Published Online:18 May 2019https://doi.org/10.1094/PDIS-01-19-0150-PDNAboutSectionsSupplemental ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Rauwolfia serpentina Benth ex. Kutz (sarpagandha) also known as snakeroot or serpentine root, belongs to the family Apocynaceae, well known for its medicinal properties to treat and cure many human diseases. During November 2016, phytoplasma-suspected typical symptoms of little leaf, dwarfing, and profuse auxiliary proliferation and ultimately severe witches’ broom symptoms were noticed on R. serpentina plants in the medicinal and herbal garden of Biswanath College of Agriculture, Assam Agricultural University, Biswanath Chariali, Assam (26.7233′N, 93.1364′E), India. The disease incidence was recorded as 12% under field conditions by visual observation of symptomatic versus nonsymptomatic plants. Fresh samples (both symptomatic and asymptomatic in triplicate) were collected and DNA was extracted, which was used as a template for direct and nested polymerase chain reaction assays primed by phytoplasma universal primer pairs of 16S rDNA region (P1/P7 followed by R16F2n/R16R2n), using previously described conditions (Schneider et al. 1997) and secA gene primer pair (SecAfor1/SecArev3 followed by SecAfor1/SecArev2) (Hodgetts et al. 2008). Approximately 1.2-kb and 480-bp amplified products were obtained, which were sequenced bidirectionally to obtain maximum length of sequence, and the consensus sequences were deposited in the GenBank with accession numbers MG721532 for 16S rRNA gene and MG721533 for secA gene. Pairwise sequence comparison of 16S rDNA and secA gene sequences of R. serpentina phytoplasma isolate revealed 99 to 100% sequence identities with strains of ‘Candidatus Phytoplasma trifolii’. The MEGA6-constructed neighbor-joining phylogenetic analysis and virtual restriction fragment length polymorphism analysis using 17 restriction enzymes of 16S rRNA gene sequences allowed affiliating the R. serpentina phytoplasma-India strain with 16SrVI-D subgroup strains with a similarity coefficient of 1.0 (Hiruki and Wang 2004). The 16S rRNA and secA gene sequences comparison confirmed the close association of phytoplasma strain associated with R. serpentina with 16SrVI-D subgroup phytoplasmas. Earlier, 16SrVI-D subgroup phytoplasma has been reported associated with various vegetables and horticultural crops in India (Rao et al. 2017). Phytoplasma diseases have been reported in over 200 medicinal plants worldwide (Marcone 2016). To the best of our knowledge, this is the first report of the association of 16SrVI-D subgroup phytoplasma strain causing little leaf, witches’ broom, and stunting symptoms on R. serpentina plant, which is an important medicinal plant species in India and has a large area under cultivation in different parts of India. Because the 16SrVI-D group phytoplasma has been reported on a new host, R. serpentina, in addition to many crop plants and weeds, the studies on the disease epidemiology and common insect vectors would be helpful in developing management strategies.The author(s) declare no conflict of interest.