Pasteuria

Abstract: The effect of nematode population density at the time of application and formulations of in vitro-produced Pasteuria spp. endospores on the final population density of Belonolaimus longicaudatus was studied in an 84-d-long pot bioassay. The experiment utilized a factorial design consisting of 30 or 300 B. longicaudatus /100 cm3 of sandy soil and three formulations of in vitro-produced Pasteuria spp. endospores (nontreated, granular, or liquid). No differences were observed in percent endospore attachment between nematode inoculum levels during either trial. Granular and liquid formulations of in vitro-produced endospores suppressed nematode population densities by 22% and 59% in the first trial and 20% and 63% in the second, respectively compared with the nontreated control. The liquid formulation increased percent endospore attachment by 147% and 158%, respectively, compared with the granular formulation. The greatest root retention by the host plant was observed at the lower B. longicaudatus inoculation level following application of the liquid formulation. While both the granular and liquid formulations reduced B. longicaudatus population densities in the soil, the liquid spore suspension was most effective.

Abstract: The bacteria Pasteuria spp. have been identified as among the most promising of several microbial organisms currently under investigation as biological control agents of plant-parasitic nematodes. As part of our goal to develop methods to discriminate isolates of Pasteuria penetrans with different host preferences, we investigated the potential of developing antibody probes to identify endospores of different isolates of P. penetrans. Polyclonal IgY antibodies were raised in chickens against endospores of P. penetrans isolates P20 and P100. Hens were injected with P20 or P100 endospore suspensions and boosted at 14 days. Anti-spore titers were determined with ELISA on yolk extracts of individual eggs as a function of time. The highest titers were found in eggs produced at 22 to 35 days after initial injections. Yolk extracts showing the highest titers were combined and processed to provide partially purified IgY preparations. SDS-PAGE and immunoblot analyses identified protein antigens with Mr values of 23-24, 46, and 57-59 KDa common to both P20 and P100 endospores. One protein antigen with an Mr value of 62 KDa was unique to the PI00 endospores. The IgY antibodies reduced the attachment of Pasteuria endospores to their nematode hosts, indicating antibody interaction with antigens on the endospore surface that are involved in the recognition and attachment processes.