CORRELATION OF METABOLIC CHANGES OF INFECTED PAULOWNIA TISSUE-CULTUREWITH PWB-MLO PATHOGENIC MECHANISM

Paulownia sp. tissue culture plantlets infected with paulownia witches ' broom mycoplasma-like organism (PWB-MLO) expressed a typical witches ' broom symptom The results determined by transmission electron micros copy and DAPI staining fluorescence microscopy showed that the severit y of the symptom was directly related with MLO concentration in the si eve tubes of the phloem. The results of the analysis of endogenous hor mones and phenolic compounds by HPLC revealed that in all cases, the f ree IAA content of the diseased plant apparently lower than that of th e healthy, and the free IAA concentration had strikingly positive corr elation with catechol concentration changes (r=0.90, n=11). The change s of cytokinin (Z+ZR, iPA), GA(3) and ABA were shown less relation wit h MLO infection. The differences of peroxidase and isoenzyme, IAA oxid ase and phenylanine ammonia lyase (PAL) between the extract of infecte d plants and that of uninfected as well as different effects of NAA an d catechol additions on MS media could further reflect the nature of t he relationship and the interaction among MLOs, catechol and the free IAA concentration.