AbstractCitrus stubborn disease (CSD) was originally discovered in California in 1915 and it has been one of the most important problems which affects the citrus industry in the East Mediterranean region of Türkiye since 1950’s. The first studies began in 1965 and were limited to survey and biological indexing until 1980s. Spiroplasma citri as the causal agent of stubborn disease was cultured for the first time from symptomatic citrus plants and other hosts in 1987 in Türkiye. Then polyclonal antisera was produced against local S. citri isolates, one dimensional gel-electrophoresis was used for further characterization and spiroplasmas were observed under scanning and transmission electron microscopes both in infected citrus tissues and also in culture. S. citri was also isolated from the Catharanthus roseus placed in citrus orchards where stubborn disease was detected and Exitianus capicola, collected from the same plots indicating the first evidence of natural possible insect transmission of stubborn disease. In the following years the epidemiological aspects of CSD were investigated in more details and new leafhopper and herbaceous hosts of S. citri were reported. Because of CSD diagnosis is difficult due to low and variable concentrations of S. citri in diseased trees and the random distribution of the pathogen, recently molecular detection techniques like PCR has been used both for diagnostic and genetic diversity studies of local S. citri isolates. The future studies will be focued on functional genomics in host-pathogen interaction using transcriptomic and proteomic approaches to learn more about the mechanisms of the S. citri pathogenicity to develop new diagnostic methods and implement plant protection strategies to control citrus stubborn disease.
Caglayan et al. (Wed,) studied this question.