The Transcriptome Analysis Of Early-infected Meloidogyne Incognita By Pasteuria Penetrans

Meloidogyne spp. is a kind of plant-parasitic nematodes and distributed widely. It is very serious harm to crops, and includes Meloidogyne incognita, Meloidogyne javanica, Meloidogyne arenaria and Meloidigyne hapla. But in our country, Meloidogyne incognita distributed most widely and the greatest harmful to crops. Pasteuria Penetrans is a class of obligate hyperparasite to Meloidogyne spp.. It can adsorbe on the surface of the nematode and enter its body. In the body, Pasteuria Penetrans can produce a large number of bacteria and wrest the nutrition of nematode. At the same time, Meloidogyne incognita can not get enough nutrition and appeared abnormal development. Thus, the number of nematodes reduced. So it is widely recognized as an effective biocontrol bacteria that prevented of Meloidogyne spp..In order to investigate the influence of Pasteuria penetrans on the changes of survival of Meloidogyne incognita and the expression of genes at the beginning of adsorption, we adsorpted Meloidogyne incognita with Pasteuria penetrans in the laboratory and observed the changes of survival of Meloidogyne incognita and the expression of genes.First, we purified Meloidogyne spp. collected from wild with single egg and identified it with molecular biology methods. Then Meloidogyne incognita was adsorpted by Pasteuria penetrans in vitro. We observed Meloidogyne incognita with microscope every day, counted the number of death Meloidogyne incognita within12days. The total RNA of Meloidogyne incognita was extracted at the third day after Meloidogyne incognita was adsorpted for transcriptome sequencing. The genes that differentially expressed were compared and the regulatory pathways were analyzed after sequencing. Finally, three genes that selected randomly from two groups of differentially expressed were verified by real time quantitative PCR.Results showed that the survival of Meloidogyne incognita infected by Pasteuria penetrans reduced. The results of transcriptome sequencing shows that the experimental group had a total of445genes changed compared with the control group, of which406genes up-regulated and39genes down-regulated.We had found that the up-regulated genes of differentially expressed significantly enriched in biosynthesis of unsaturated fatty acid, the down-regulated genes of differentially expressed were significantly enriched in metabolism of xenobiotics by cytochrome P450pathway with the analysis and comparison on the basis of KEGG database. In order to verify the reliability of this method, six genes that selected randomly from the differentially expressed had been confirmed. The results indicated that the expressions of the six genes were consistent between the real time PCR and transcriptome sequencing.Pasteuria penetrans could reduce the survival of Meloidogyne incognita at the beginning of adsorption. The screened up-regulated genes of differentially expressed by transcriptome sequencing enriched in biosynthesis of unsaturated fatty acid. The activation of this pathway could improve the immune function of Meloidogyne incognita and help to prevent Pasteuria penetrans. However the screened reduction genes of differentially expressed were significantly enriched in metabolism of xenobiotics by cytochrome P450pathway. This suggested that in order to infect Meloidogyne incognita and parasitic in the body, Pasteuria penetrans reduced the expression of genes in metabolism of xenobiotics by cytochrome P450pathway at the beginning of adsorption. So, the innate immune and detoxification mechanisms of Meloidogyne incognita was suppressed and interference by this method.