ANALISIS HISTOPATOLOGICO EN TUBERCULOS DE DOS VARIEDADES DE PAPA ANDINA (SOLANUM TUBEROSUM SUBSP. ANDIGENUM) INFECTADAS POR ESPECIES DEL GENERO MELOIDOGYNE
Tordable, M. del C., P. Lax and M. E. Doucet. 2008. Histopathological analysis of tubers of two varieties of Andean potato (Solanum tuberosum subsp. andigenum) infected by species of the genus Meloidogyne. Nematropica 38:95-103. Histological alterations induced by Meloidogyne javanica alone and in combination with M. incognita were studied in tubers of Andean potato (Solanum tuberosum subsp. andigenum) 'Collareja' and 'Tuni' from Argentina, respectively. No galls were observed on the surface of the infected tubers. Nematodes colonized the cortical parenchyma causing the formation of brown spots associated with mature females with their egg masses. Nematodes induced hyperplasia of the parenchyma. Some cells showed hypertrophy and modified their cytological characteristics to generate the giant cells. Although the tuber qualitative damage and histological alterations were similar in both varieties, it was possible to observe a hypersensitive reaction in 'Collareja' tubers. This reaction consisted of formation of thick walls, reinforced and impermeabilized by suberin deposits in the cells surrounding the nematode female, eggs masses and juveniles. This reaction may have prevented the subsequent reinfection by the nematode second-stage juveniles. The cytology of the giant cells, as well as the abun-dance of juveniles and females located in the tubers of the 'Tuni' variety, suggests a more susceptible host response.