Isolation And Identification Of Pasteuria Penetrans

Root-knot nematodes, which affect the majority of arable and vegetable crops, are likely to become increasingly important pests around the world. As the hyperparasite of root-knot nematodes Meloidogyne spp., Pasteuria penetrans has a great potential to be developed as a biocontrol agent.In order to obtain resources of Pasteuria penetrans,76 roots and corresponding soil samples were collected from 19 different plants in Hainan, China.Six strains, numbered PPh01-PPh06, were isolated from 76 samples according to light microscopy. The host nematodes were related to Meloidogyne incognita, Meloidogyne javaniva, Meloidogyne arenaria and Meloidogyne enterolobii, and host plants related pepper and bananas, soil type related to sandy loam and loam.Three methods of wall-breaking including grinding menthod, quartz sand-beating method and ultrasonic crushing treatment were adopted to break endospore wall in this paper. Results showed that quartz sand-beating method was the best one.Transmission electron microscopy (TEM) showed the six strains to be morphologically similar with Pasteuria penetrans. A phylogenetic tree was constructed with Mega 4.0 from sequences available in GenBank and of six strains from this study, it showed that six stains formed two distinct groups, strains PPh01 and PPh06 gathered to the same group with Pasteuria penetrans. The similar indentity was 99% Between the two strans and Pasteuria penetransT; the other 4 strains stayed in another group, and shared shared 97% similar indentity with Pasteuria penetransT, which are probably a new group within Pasteuria.In order to detect Pasteuria penetrans in soils, We had improved the soil DNA extraction method, and the Pasteuria-specific PCR primers 617f/1166r was used for the detection of Pasteuria penetrans in soil. Results revealed Fastprep cell disrupt method was the prime one, its detection limits for soil DNA were 1000 Pasteuria penetrans endospores (g soil)-1...