The resistance of tomato plants (Solanum Lycopersicum L.) to M. incognita, M. javanica and M. arenaria, provided by the presence of Mi gene, does not include the species M. enterolobii (=M. mayaguensis). The aim of this study was to verify the anatomical changes caused by M. enterolobii in the root system of rootstocks from tomato plants with Mi resistance gene ('Magnet' and 'Helper M') and to compare these changes with those caused by M. javanica. The anatomical observations of roots were done with the aid of a light microscope and the most relevant aspects were photographed. Based on counts and measurements of the size of feeding sites and giant cells, the data were analyzed by using the statistical method of Cluster Analysis. The emergence of nurse cells stimulated by M. enterolobii was observed for both tomato rootstocks between 10 and 17 days after inoculation (DAI). The number and the area of feeding sites and giant cells were smaller at 17 DAI than at 24 DAI. On the latter occasion (24 DAI), there were feeding sites established by the presence of several multinucleate nurse cells with thick cell walls and dense and granular cytoplasm. Vascular tissues were compressed and disorganized; there was also hypertrophy of cortical parenchyma cells. Roots inoculated with M. javanica did not show anatomical changes.
Nurse cells; Histopathology; Nematology
