engleski

Effect of phytoplasmas on rooting efficiency of the periwinkle host

Recovery, as a remission of symptoms in phytoplasma- infected plants, which may or may not involve elimination of the pathogen from the host, can be induced in periwinkle shoots by the supplement of indole-3-butyric acid (IBA). After prolonged IBA treatment efficiency of rooting was compared for healthy shoots ; recovered shoots with a high titer of phytoplasma strains EY-C and SA-I ; and recovered shoots in which upon the IBA-treatment HYDB phytoplasma strain was undetectable or present in a low titer. On the medium with the same concentration of IBA, number of rooted shoots decreased with statistical significance, following the trend: healthy shoots >HYDB strain recovered shoots>EY-C and SA-I recovered shoots. Furthermore, after the rooting experiment, HYDB phytoplasma was detected in all the tested unrooted shoots while among the rooted periwinkles only 20% were positive. These results correlate for the first time the presence and the titer of phytoplasmas with the efficiency of rooting of periwinkle host. Since auxines are phytohormones involved in the initiation and emergence of adventitious roots, reduced rooting efficiency may reflect the reduced levels or disturbed transport of auxin/auxins in phytoplasma-infected periwinkles.

antiphytoplasmal activity; auxin; bacteria

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