Attachment of endospores of Pasteuria penetrans to males and juveniles of Meloidogyne spp.

Abstract

Abstract The attachment of endospores to Meloidogyne spp. males and second stage juveniles (J2) was evaluated in two different in vitro assays of seven isolates of Pasteuria penetrans from Florida, USA. In the first assay, endospores of all seven isolates adhered to J2 but not males of M. arenaria race 1. In the second assay, two isolates differed in the specificity of spore attachment to J2 of six Meloidogyne spp. Isolate B4, from Pratylenchus scribneri, showed a similar degree of attachment to J2 of M. arenaria race 2, M. javanica (two populations) and to M. incognita race 3, but did not attach to males of seven species. Isolate P100, from Meloidogyne sp., had high rates of attachment to M. javanica from Rio Grande do Sul State and to M. paranaensis, but lower rates to M. arenaria and M. javanica from Parana State. These data indicate that attachment ability depends not only on the Meloidogyne species but also on the particular population of a species. The high rate of attachment to male but not J2 M. hapla indicates that endospore attachment may also depend upon nematode stage, species, race and population and on Pasteuria isolate. Germinated endospores attached to male M. hapla were examined by scanning electron microscopy but few had successfully penetrated the cuticle. Adhesion des endospores de Pasteuria penetrans aux males et juveniles de Meloidogyne spp. - L'adhesion des spores de Pasteuria penetrans aux males et juveniles de deuxieme stade (J2) de Meloidogyne spp. a ete evaluee lors de deux differents tests in vitro comprenant sept isolats de P. penetrans provenant de Floride, USA. Lors du premier test les endospores des sept isolats ont adhere aux J2 mais non aux males de M. arenaria race 1. Lors du second test deux isolats se sont distingues quant a la specificite de l'adhesion de leurs spores aux J2 de six des especes de Meloidogyne. L'isolat B4, provenant de Pratylenchus scribneri, montre un taux d'adhesion similaire vis-a-vis des J2 de M. arenaria race 2, M. javanica (deux populations) et M. incognita race 3, mais n'adhere aux males d'aucune des sept especes. L'isolat P 100, provenant de Meloidogyne sp., Montre un taux d'adhesion eleve vis-a-vis tant de M. javanica provenant de l'Etat de Rio Grande del Sul que de M. paranensis mais ce taux est faible vis-a-vis de M. arenaria et M. javanica originaires de l'Etat du Parana. Ces donnees indiquent que la faculte d'adhesion depend non seulement de l'espece de Meloidogyne en cause mais egalement de la population particuliere de cette espece. Le taux eleve d'adhesion vis-a-vis des males, mais non des J2, de M. hapla indique que cette adhesion peut dependre du stade de developpement du nematode, de son espece, race ou population ainsi que de l'isolat lui-meme de P. penetrans. Les endospores fixees aux males de M. hapla, et ayant germe, ont ete examinees en microscopie electronique a balayage: peu d'entre elles avaient reussi a traverser la cuticule.