PLANT-PARASITE-ENDOPHYTIC BACTERIA TRIANGLE: THE MICROBIOME OF PARASITIC WEED AND ITS HOST

Phelipanche and Orobanche species (broomrapes) are holoparasitic plants that connect to the vascular systems of their hosts, allowing the transfer of various substances including a possible exchange of endophytic bacteria that inhabit the internal tissues of both plants. To shed light on the microbial aspects of the parasitic interaction between Phelipanche aegyptiaca and its host, tomato, we characterized the endophytic composition in both plants before and after attachment. Endophyte communities of the parasitic weed were significantly different from that of the nonparasitized tomato root but no significant differences were observed between the parasite and its host, parasitized tomato root, suggesting bacterial exchange between these two plants. Endophytic community composition of P. aegyptiaca stages showed a clear shift from gram negative to gram positive bacteria during the development of the parasitic weed. Endophytic bacteria isolates were examined for their ability to secrete substances that may affect the dynamics of host – parasite interaction (pectin degrading enzymes - possibly facilitating parasite penetration to its host, and inhibitory substances – possibly protecting the host against its parasite). The current study focuses on the bacterial aspect of host – parasite interaction and highlights the potential of exploiting alternative environmentally friendly approaches for parasitic weed control.