Evaluation of the Efficacy of Arbuscular Mycorrhizal Fungi in Enhancing Resistance of Lycopersicon esculentum Roots Against Fusarium oxysporum Wilt Disease

Abstract

   The objective of this investigation was to study the effects of amixture of three arbuscular mycorrhizal species : Glomus etunicatum , G. leptotichum and Rhizophagus intraradices on the induced resistance of Lycopersicon esculentum roots infected with Fusarium oxysporum f.sp.lycopersici which is causal agent of wilt in the presence of organic matter peatmose (O). The work was achieved in aplastic house ( Shed) using pot culture planted for 10 weeks. Results indicated significant increase of all mycorrhizal colonization parameters ( F% , M% , m% , a% , A% ) . Highest percentage of mycorrhization was detected in roots infected with the pathogen 4 weeks after mycorrhizal colonization . On the other hand least colonization was shown in the dual inoculation treatment when both organisms were added together at the beginning of plantation . Mycorrhization resulted in significant reduction of disease severity in all treatments compared to the control ones. , and the trio treatment (O×F.o.l.×M) showed the highest reduction in percentage of disease severity after 4 weeks of infection with the pathogen . Moreover , mycorrhizal colonization significantly increase the activity of antioxidant enzymes tested ( SOD , POD , CAT , PAL , PPO , GPOX ) in infected roots , Highest enzymes activity was recorded in dual treatments ( F.o.l. × M ) followed by the trio treatment (O×F.o.l.×M) . On the other hand all treatments amended with organic matter resultrd in signifant  reduction  off all enzymes activity tested.