Monoclonal antibodies for the detection of Tagetes witches' broom agent [Tagetes patula L. - Tagetes erecta L.]

English. Tagetes Witches'Broom disease (TWB) was first recorded in Italy in 1958, and in 1972 a phytoplasma was associated with the disease. Infected Tagetes patulus plants were used as source of inoculum for phytoplasma transmission to Catharanthus roseus. The phytoplasma was also back-transmitted from C. roseus to T. patulus and T. erectus by dodder. Three monoclonal antibodies (Mabs) were obtained against the TWB agent (TWBa); all belonging to subclass IgG1. Using ELISA and DIBA (dot immunobinding assay) it was possible to detect TWBa in experimentally inoculated periwinkle and Tagetes, and in naturally infected Tagetes. The specificity of the Mabs was also evaluated by ELISA checking 30 phytoplasmas isolated on perwinkle from different herbaceous and woody plants. Serological correlation was observed only between TWBa and a phytoplasma isolated from a yellows-infected grapevine

Italian. La malattia degli scopazzi del tagete (TWB) e' stata segnalata in Italia nel 1958, e nel 1972 un fitoplasma e' stato associato alla fitopatia. Piante di Tagetes patulus infette sono state usate come sorgente d'inoculo per la trasmissione del fitoplasma a piante di Catharanthus roseus. Il fitoplasma e' stato inoltre trasmesso di ritorno da C. roseus a T. patulus e a T. erectus usando la cuscuta. Sono stati ottenuti 3 anticorpi monoclonali (Mabs) specifici per l'agente di TWB (TWBa), tutti appartengono alla sottoclasse IgG1. I tre Mabs, in ELISA indiretto, in DAS-ELISA e in DIBA (dot-immunobinding assay) hanno permesso di diagnosticare TWBa sia in pervinca e tagete inoculati sperimentalmente, sia in tageti con infezione naturale. La specificita' dei Mabs e' stata valutata in ELISA indiretto con 30 fitoplasmi, isolati su pervinca da diverse piante erbacee ed arboree. Correlazione sierologica e' stata osservata solo tra TWBa ed un fitoplasma isolato da vite affetta da giallume