Diverse phytoplasmas associated with maize bushy stunt disease in Peru

Corn plants showing symptoms of midribs chlorosis, and leaf reddening, short internodes, ear proliferation, and plant growth reduction were collected in Peru from fields in nine localities in the provinces of Huancayo, Chupaca, and Jauja in the Junin region, and tested to verify phytoplasma presence and identity. Primers amplifying the phytoplasma ribosomal 16S and ribosomal protein genes were used. The phytoplasma presence was detected in symptomatic samples from all the surveyed areas. The sequencing of the obtained amplicons indicated the presence of 'Candidatus Phytoplasma asteris' and 'Ca. P. pruni'-related strains. A BLASTn search of sequenced genes showed that the two 'Candidatus Phytoplasma' strains identified in corn shares 100% and 99.82% identity with the 'Ca. P. asteris' strains from maize and 99.92% and 99.55% with 'Ca. P. pruni'-related strains, respectively. The RFLP analyses allowed to enclose these phytoplasma strains in the 16SrI-B and 16SrIII-J subgroups; however, the two phytoplasmas were, in some cases, present in mixed infection. The 16SrIII-J phytoplasma is for the first time reported associated with the maize bushy stunt disease and this represent a relevant information for the disease epidemiology towards its appropriate management in the affected area.

Automated summary

Corn plants in Peru with multiple symptoms were found to be infected by 'Candidatus Phytoplasma' strains related to aster and pruni. The presence of these phytoplasmas in maize and their association with the maize bushy stunt disease provide important information for disease management.