Persistence and spread of mycoplasma in axenic callus tissue cultures of tobacco (Nicotiana glauca Grah.) in the presence of kinetin and IAA in nutrient medium

Abstract

A technique is described for the establishment of infectious axenic callus cultures originated from stems of tobacco plants suffering from a mycoplasma disease, potato witches' broom. When stem pieces from a diseased tobacco plant (Nicotiana glauca Grah.) are culture on a modified nutrient medium according toMurashige andSkoog (1962) with added kinetin (0.64 mg or 2.56 mg 1 000 ml−1) and IAA (2 mg or 4 mg 1 000 ml−1), the pathogen persists and spreads in the newly formed callus tissue. The presence of the pathogen was proved by implantation of callus slices into stems of tomato plants which indicate the disease very reliably. Reconstituted tobacco plants too recovered the infectious agent of potato witches' broom; 27 plants from the 35 reconstituted plants were diseased. Similar results were obtained with Crimean yellows. Calli were cultured and subcultured from 1 to 18 monthsin vitro and some infectious cultures are maintained and their investigation goes on. We suppose that kinetin plays a very important role for infectivity preservation in callus cultures.