THE First REPORT OF PASTEURIA SPP. ATTACHING HETERODERA GLYCINES IN CHINA
PASTEURIA SPP. ATTACHING HETERODERA GLYCINES IN CHINA
DELIANG PENG and DONGSHENG ZHANG
Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100094, P.R. China
Background and objectves
Pasteuria spp. the mycelial and endospore-forming bacterial obligate parasites of plant-parasitic nematodes, have been demonstrated as effective biological control agents of plant nematodes in greenhouse and microplot experiments and in the field (1). These organisms have been found on a variety of nematode hosts and in many different climates and environmental conditions throughout the world. Thses organisms current consist of three species, Pasteuria penetrans (Thorne) Sayre & Starr which primarily parasites root-knot nematodes, Meloidogyne incognita (Kofoid & White) Chitwood; P. thomei Starr & Sayre, is specific mainly to root-lesion nematodes, Pratylenchus brachyurus Godfrey; andP.nishizawae . The third species of this bacterial parasite, parasitizes the adult female of Heterodera and Globodera. The soybean cyst nematode, Heterodera glycines Ichnohe, is widespread in North China. Recently, population densities of H. glycines declined in Shandong province, China and endospores of a Pasteuria spp. were observed on second-stage juveniles (J2). In this report, we describe the first natural occurrence of Pasteuria spp. on H.glycines and our preliminary observations on the morphology.
Material and methods
Soil samples were collected from fields on Nanwangzhu village, Jiaozhou city, Shandong province, China in October, 1995. Second-stage juveniles and other vermiform nematodes were extracted, killed with gentle heat and fixed in 4% formalin, processed to glycerine by a slow method and mounted in anhydrous glycerine and measured.
Results and conclusion
Population densities of H. glycines, race 7, were found to decline, two to seven endospores of Pasteuria spp. were observed to attach second-stage juveniles (J2) of H. glycines but endospores were not found attached to other genera, including Aphelenchus, Helicotylenchus, Tylenchorynchus and Pratylenchus, were not encumbered with endospores. More surveys of Pasteuria spp. from different crops from Northeast, Southwest, and North China revealed isolates of Pasteuria spp. attached to PararotylenchusHelicotylenchus spp.Rotylenchus spp., but not Heterodera glycines.
1 Sayre, R.M.,et al. 1988. Proc. Helminthol. Soc. Wash. 55 :28-49.
2.Sayre, R. M.,et.al. 1991. Res. Microbiol. 142:551-564.