engleski

Change of exogenously supplemented plant growth regulator causes recovery of phytoplasma-infected periwinkles

Phytoplasmas (genus ‘ Candidatus Phytoplasma’ ) from the class Mollicutes, are wall-less, non-helical, endocellular prokaryotes that inhabit plant phloem and insects. These bacteria with reduced genome cause numerous economically important diseases infecting several hundred plant species worldwide. Since phytoplasmas cannot be cultivated on artificial media, they are usually maintained in Catharanthus roseus shoots grown in vitro on MS medium supplemented with benzylaminopurine (BA). In such a system, phytoplasmas are present in a high titer.The aim of our research was to examine the influence of indole-3-butyric acid (IBA) on C. roseus shoots infected with three different phytoplasma strains. A change from BA to IBA supplemented in the medium supported plant growth, photosynthesis and remission of symptoms in all phytoplasma-infected shoots, but had no effect on the presence of two phytoplasma strains in tested tissues. However, after the 4th subculture, HYDB phytoplasma strain was undetectable in more than 60% of the tested shoots. After one year of IBA treatment, HYDB-infected periwinkle shoots were retransferred to the medium supplemented with BA. Some of the shoots showing remission of symptoms during the IBA treatment permanently recovered from the infection and remained negative when tested for phytoplasma presence. This is the first report on differential influence of plant growth regulators on phytoplasma-infected plants.

indole-3-butyric acid; phytoplasma; plant tissue culture

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