Beta-Glycosidases from Meloidogyne incognita and M. javanica.

B-glycosidases have been implicated in plant pathogenesis by numerous authors (6,8,9,10). B-glucosidase from Pratylenchus penetrans was reported to hydrolyse HCN from a cyanogenic glucoside (amygdalin) during pathogenesis of peach roots (7), and the activity of B-glucosidase from preparasitic larvae of Heterodera rostochiensis has been correlated with the ability to parasitize resistant potato lines (13). Currently, data is not available on the types and amounts of B-glycosidase activity associated with root-knot nematodes. Objectives of this study, therefore, were to determine the types of B-glycosidase activities associated with Meloidogyne incognita (Kofoid and White 1919) Chitwood 1949 and M. javanica (Treub 1895) Chitwood 1949 and to compare these enzyme activities to those associated with host root tissues. Nematode populations were reared on Lycopersicon esculentum Mill. 'Rutgers' under greenhouse conditions (24 + 4 C). Adult females were obtained from root tissue 40 d after inoculation as described by Hussey (2). Preparasitic second-stage larvae were collected as described by Vrain (12). Root tissue consisted of excised root-knot galls from tomato 35 d after inoculat ion of M. javanica and root apices (terminal 2 cm) from uninoculated plants of similar age. Crude homogenates of nematode samples were prepared as described by Hussey et al. (3). Nematodes were surface sterilized with 0.1% chlorhexidine acetate then rinsed three times with cold, sterile 0.01 M PO4 buffer (pH 7.5) containing 0.85 NaCI and 0.001 M MgClv Samples were homogenized