Attachment of Pasteuria penetrans Endospores to Meloidogyne spp. Juveniles Affected by Temperatures and the Nematode species

摘要

A greenhouse soil infested with an obligate nematode parasitic bacterium, Pasteuria penetrans, was used to test the effect of temperatures on the endospore attachment to root-knot nematode, Meloidogyne armaria, juveniles (J2). Freshly hatched J2s wereinoculated to the soil in petri dish and incubated under different temperatures of 20°C, 25 °C, 30°C, and 35°C for 7 days. The endospore attachment rates were 100% in all the temperatures, while the number of endospores attached per J2 was highest in 25 °C with 28.3 endospores/J2 followed by 20.2,18.6, and 13.6 in 3 0 °C, 20 °C, and 35 °C, respectively. When the soil was pre-treated under different temperatures before the J2 inoculation, the endospore attachment rates significantly decreased from 60% in room temperature to 25.0,31.7,8.3, 5.0, and 0% after the soil incubation in -30 °C, 4 °C, 40 °C, 50 °C, and 100 °C for 10 days, respectively. The endospore numbers attached per J2 were 3.5, 4.3, 1, 1, and 0 when the soil was pre-treated in-30°C, 4°C, 40 °C, 50°C, and 100 °C, respectively, which were lower than 5.3/J2 of room temperature treated soil. The P. penetrans isolate in the soil showed nematode species-specific endospore attachment characteristics with 100% attachment rate only on M. arenaria J2s while the rates were 0% on M. hapla and M. incognita J2s.