Characterization of phytoplasmas related to peanut witches'-broom and stolbur groups associated with alfalfa diseases in Iran

摘要

In the central and south eastern provinces of Iran, alfalfa plants showing phytoplasma diseases-like symptoms categorized into three major types, namely witches'-brooms, little leaf and yellowing, were observed during 2008 and 2009. Phytoplasmas weredetected by PCR assays using phytoplasma universal primer pair P1/P7 followed by nested PCR using primer pair R16F2n/R16R2. PCR results confirmed the phytoplasma infection in symptomatic alfalfa plants. Restriction fragment length polymorphism (RFLP) andsequence analysis of partial 16S rRNA gene from the Iranian alfalfa phytoplasmas indicated that phytoplasmas of the 16SrII and 16SrXII groups were associated with alfalfa witches'-broom and alfalfa yellows, respectively, while phytoplasmas of the 16SrII-D subgroup are associated with alfalfa little leaf disease. This research is the first study to report stolbur phytoplasmas as causal agents of alfalfa yellows and 16SrII-D phytoplasmas as causal agents of alfalfa little leaf diseases in Iran.