Histopathological analysis of roots of vitis vinifera cultivar cabernet sauvignon infected with meloidogyne ethiopica

Root tissues of grapevine cv. Cabernet Sauvignon from the locality of El Huique (VI Región, Chile), parasitized by M. ethiopica, were analyzed to evaluate the host-parasite association. Root segments with and without galls were fixed and processed following conventional techniques for optical microscopy. Galls in central and lateral positions relative to the root axis were observed. Central galls showed increase in the diameter of the central cylinder due to the presence of hyperplastic tissue. In addition, in this zone the nematode induced the formation of giant cells that were observed at different development stages: initial, differentiated and non-functional. Giant cells were embedded in the widest rays of secondary xylem, disrupting and reducing this tissue as well as the vascular cambium. In lateral galls, the central cylinder of the roots had hyperplastic tissue containing cavities communicated with the root periphery. The histopathological reaction observed in roots showed the susceptibility of the grape cv. Cabernet Sauvignon to the local M. ethiopica population.