Histopathological analysis of peanut roots (Arachis hypogaea) attacked by Meloidogyne arenaria.

TORDABLE, M. DEL C.; SUAREZ, S.; LAX, P.; PEDELLINI, R.; DOUCET, M.E

Coimbra

Congreso; XLIII Reunión Anual de la Organización de Nematólogos de los Trópicos Americanos (ONTA).; 2011

Organización de Nematólogos de los Trópicos Americanos (ONTA).

Peanut plants cv Granoleico severely attacked by Meloidogyne arenaria were recently detected at the Módulo Experimental FMA (Fundación Maní Argentino)-INTA General Cabrera (province of Córdoba, Argentina). Root samples (galled and non-galled) were fixed in FAA, processed and analyzed using conventional optical microscopy techniques. Galls were round, less than 3 mm in diameter, and had numerous egg masses on them. Some galls had several lateral roots. In the central cylinder, feeding sites (FS) were observed embedded in vascular tissues, which were reduced, displaced and showing atypical arrangement. In galls containing more than one female (up to four were found, each associated with its FS), these alterations were more severe. The body of females occupied part of the cortex, damaging surrounding cells. FS were composed of a variable number of giant cells (up to six) that developed from cells of vascular tissues. Cells showed marked hypertrophy (up to 200 µm measured at the major axis), dense cytoplasm, nucleus division (several nuclei arranged in clusters per cell) and development of internal cell wall ingrowths in sectors adjacent to the xylem. Juveniles of the nematode were observed in diverse zones of the galls. The peanut cultivar showed to be very susceptible to M. arenaria.