Development of Cloned DNA Probes for Phytoplasma Associated with Loofah Witches’ Broom

Abstract

AbstractDNA was isolated from periwinkle (Catharanihus roseus) infected with a phytoplasma that originated in loofah witches’ broom affected by loofah. Cloned DNA inserts from six LfWB‐phytoplasma specific recombinant plasmids were not only labelled with digoxigenin, but also used as probes. Probes hybridized with DNA derived from LfWB‐phytoplasma affected periwinkle and loofah, but not with DNA from healthy plants or plants infected with phytoplasmas associated with elm yellows, red bird cactus, peanut witches’ broom, paulownia witches’ broom, Ipomoea obscura witches’ broom, aster yellows (two isolates), and sweet potato witches’ broom obtained with DNA from different phytoplasmas experimentally maintained in periwinkle. The probes could detect LfWB‐phytoplasma DNA with as little as 16 ng and 32 ng of DNA from periwinkle and loofah, respectively. The method proposed herein provides a means for specifically detecting and identifying of loofah witches’ broom phytoplasma, as well as confirming the notion that this phytoplasma represents a distinct strain cluster,