Characterization of sunn hemp witches' broom phytoplasma in Myanmar

Abstract

Sunn hemp is a tropical or subtropical plant of the legume family, and used as green manure and lignified fiber. Chlorotic leaves, internodes shortening, reduced sized leaves and shoot proliferation symptoms were observed on sunn hemp in a number of fields around Yezin area, Myanmar. To determine possible association of a phytoplasma with the disease, DNA amplifications were conducted by polymerase chain reaction (PCR) using a universal phytoplasma primer pair, SN910601/SN011119 that amplified 1.8 kb fragments encoding the entire 16S rDNA, the 16S-23S intergenic spacer region and the beginning of 23S rDNA. Phytoplasmal rDNA was amplified in the PCR, indicating that phytoplasma was associated with the disease and designated sunn hemp witches' broom (ShWB) phytoplasma. On the basic of nucleotide sequence analysis of 16S rDNA and phylogenetic analysis, the ShWB phytoplasma was closely related to strains SUNHP from diseased sunn hemp in Thailand which are classified in 16SrII group. Results of putative restriction fragment length polymorphism maps showed that the ShWB phytoplasma belonged to subgroup 16SrII-A. This report is the first observation and molecular characterization on sunn hemp witches' broom phytoplasma in Myanmar.