Emerging incidence and diversity analysis of sugarcane grassy shoot phytoplasma in western Uttar Pradesh, India

A survey conducted during 2017–2020 in Meerut, Muzaffarnagar and Saharanpur districts of Uttar Pradesh, India revealed the presence of symptoms of sugarcane grassy shoot (SCGS) disease with high incidence in the major commercial sugarcane varieties. Symptomatic along with asymptomatic sugarcane leaves were examined for phytoplasma detection by polymerase chain reaction (PCR) assays, using specific nested 16S rRNA primers (P1/P7 and R16RF2n/R16R2). The nested-PCR assays confirmed 61 out of 94 sugarcane samples as phytoplasma positive. The phylogenetic study revealed that these sugarcane phytoplasma strains showed the closest relationship with the ‘Candidatus Phytoplasma oryzae’. Ribosomal group identification through in silico RFLP analysis demonstrated that SCGS phytoplasma strains sequenced from Meerut belongs to 16SrXI-B subgroup. These results confirmed the emergence of SCGS disease in the major sugarcane varieties in the three districts of western of Uttar Pradesh, which are the major sugarcane growing areas in India. This finding needs immediate attention and provide clear indications to the farmers, for the use of hot water treated propagation materials, replacement with resistant varieties and overall adoption of improved and specific agronomic practices for the disease management.