engleski

Biochemical and epigenetic changes in phytoplasma-recovered periwinkle after indole-3-butyric acid treatment

Phytoplasmas cause deregulation of developmentally important genes in infected hosts and disturb the normal transport through the phloem causing numerous physiological and biochemical changes including the changes in plant growth regulators balance. This fact was the basis for the idea to try to eliminate phytoplasmas by treating infected plants with auxins. In vitro grown Catharanthus roseus shoots infected with different ‘Candidatus Phytoplasma’ strains were treated with two auxins. Tested plant growth regulators, indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA), induced remission of symptoms (recovery) in all phytoplasma-infected plants (Perica et al., FEMS Microbiol. Lett., 268, 171-177. 2007 ; Perica, J. Appl. Microbiol., 105, 1826-1834. 2008 ; Ćurković-Perica, Chem. Croat. Acta 81, 641-646. 2008). The time period and concentration of the auxin needed to induce recovery was dependent on the ‘Candidatus Phytoplasma’ strains and the type of auxin. IBA-treatment eliminated ‘Ca. P. asteris’ (strain HYDB) from the host while two other strains, ‘Ca. P. ulmi’ (strain EY-C) and ‘Ca. P. solani’ (strain SA-I) persisted in the host tissue despite the obvious recovery of infected plants. To elucidate the possible mechanism of host recovery and ‘Ca. P. asteris’ elimination from C. roseus shoots caused by IBA treatment, H2O2 and related enzymes, endogenous auxin levels and general methylation levels were measured and compared for infected, non-infected and recovered periwinkles. Differences in methylation of the plant host genome after the treatment with IBA revealed that epigenetic changes might be responsible for the elimination of ‘Ca. P. asteris’ from the infected periwinkle. At the moment, a similar experiment is conducted on Vitis vinifera.

auxin; genom methylation; phytoplasma; recovery

nije evidentirano