PHENOLIC METABOLISM IN RESISTANT AND SUSCEPTIBLE PEACH ROOTSTOCKS TO NEMATODE AFTER INOCULATION WITH Meloidogyne incognita

摘要

PAL level and the content of soluble phenols were enhanced in both Rancho Resistant (RR) and GF677, respectively resistant and susceptible peach rootstocks, after inoculation with nematode. RR had a higher peroxidase level than GF677 both before and after inoculation, while in the latter the peroxidase levels increased to a certain extent only at a later stage of nematode infestation. When RR shoots were grafted on GF677, there was a tendency in the reduction of the gall number in GF677 roots, but nophysiological interaction was found in the reciprocal graft. It was hypothesized that the higher content of soluble phenols and PAL level, induced by the nematode attack, was a common feature of both rootstocks; however, in RR it was a higher level of some anionic peroxidase isozymes that halted the nematode development by catalyzing soluble phenols: they promoted nematode development by inhibiting indolacetic acid oxidase which controls the level of IAA.