Abstract
Root-knot nematode (Meloidogyne spp.) is widespread throughout the world and directly responsible for heavy damages in numerous economic crops. Indirectly, they are responsible for the environmental contamination resulting from using chemical nematicides. Therefore, 3 types of algal alginates (Colpomenia sinuosa, Turbinaria turbinate and Cystoseira myrica), in addition to sodium alginate were tested against the M. javanica (Treub) Chitwood infecting eggplant (Solanum melongena L.) under greenhouse conditions. Fourier Transform Infra-Red (FTIR) analysis of alginate extracted from algae and commercial alginate showed very small variation among the functional groups and the presence of the very weak band corresponding to sulfate functional group in sodium alginate (standard). All types of alginates significantly reduced development and reproduction of the nematode compared to untreated infected plants (that is mean: control with nematode only without adding any treatments). The results of C. myrica treatment surpassed the other alginate treatments in reducing nematode criteria. On the other hand, increasing of eggplant growth parameters was noticed for all treatments. Changes in the pattern of DNA profile in eggplant samples in all alginate treatments compared to healthy plants were documented, using RAPD Marker, while little changes were observed using EST markers. The results suggest that the infection of eggplant with M javanica and most of alginate treatments cause DNA profile change with different degrees compared to the treatment of chemical control with the nematicide oxamyl. Noteworthy, the lowest effect of the alginate application of DNA change could be obtained from using either the alginate extracted from the alga T. turbinata or sodium alginate treatments, except when using primer OPR2 which showed the highest changes in the pattern of DNA profile.