A phytoplasma representative of a new subgroup 16SrI-Z associated with Bunchy Top Symptoms (BTS) on papaya in Cuba

Phytoplasmas are associated with two papaya diseases in Cuba, Papaya Bunchy Top (PBT) and Bunchy Top Symptoms (BTS), which decrease fruit production. Assessment of the 16S ribosomal DNA by nested PCR, conventional RFLP, sequencing, and in silico RFLP analyses allowed the identification of a new phytoplasma subgroup designated BTSp-16SrI-Z associated with BTS disease in the eastern region of the country. BTSp-16SrI-Z subgroup was detected in 60.42 % of the surveyed plants with crown leaf chlorosis and necrosis of the young leaves. Results confirmed that this phytoplasma strain was consistently associated with the observed BTS symptoms, implying new epidemiological constraints for the disease management