Investigation of the defense genes expression of Phenylalanine Ammoniumase and Peroxidase in interaction with Neem extract of and Meloidogyne javanica nematodes in tomato

The aim of this research was to investigate the effects of different concentrations of Azadirachta indica )neem( aqueous extract on the expression of the encoding genes of the two phenylalanine ammonialysis and peroxidase enzymes in tomato (Matin and Early Urbana cultivars) in the interaction with root knot nematode caused by Meloidogyne javanica. The tomato seedlings were inoculated in the 4-6 leafed stages with different concentrations of the neem extract and then incubated with the pathogen. The plants sampling were at six time points (0, 12, 24, 96, 192 and 288 hours) after pathogen inoculation. The gene expression of the defense enzymes was investigated using the Real-time PCR techniques. In both cultivars, the gene expression of POX and PAL enzymes in the combined treatment of the pathogen nematode and the aqueous neem extract had increasing trend with significant difference with the control. In Matin cultivar, the increase of the gene expression was higher and faster than of Early Urbana cultivar, so that the expression of PAL and POX genes in this cultivar was 18.2 and 14.5 times more than the control. In the early Urbana cultivar, the highest rate of PAL gene expression was observed at 19.2 hours and was 7.5 times, and in the case of POX gene at 96 hours and 3.9 times when it was compared with control. In greenhouse experiments, the nematode pathogenicity indexes showed a significant decrease compared with the Early Urbana cultivar. According to the results, in order to protect the plant against the invasions of the patients, the expression of the defensive genes should be increased at the earliest stages after the inoculation of the patient. Early increase in expression of genes in the seedlings treated with neem extract seems to be a justifiable phenomenon in the plant resistance to the pathogenic agent.