The Function Of Lecanicillium Lecanii And Its Proteins Against Myzus Persicae And Galleria Mellonella Larvae

Green peach aphid,Myzus persicae?Sulzer??Hemiptera:Aphididae?,is an important cosmopolitan pest of many Solanaceous crops including tomato.The entomopathogenic fungus Lecanicillium lecanii?Zimmerman??Hypocreales:Clavicipitaceae?has a great potential to control this aphid pest.In this work,we compared three isolates of entomopathogenic fungus L.lecanii formerly identified as Verticillium lecanii?V-2,V-3 and V-5?in different forms?conidia,filtrate,Binary combination?conidia+filtrtate?and partially purified protein?to evaluate the virulence potential against M.persicae,and also tested the role of partially purified protein in the defense response of tomato plant against M.persicae.Furthermore,we isolated a cuticle degrading chitinase from L.lecanii using in silico techniques and tested the activity against Galleria mellonella larvae.The main results were summarized as follows;?1?Virulence potential against M.persicae was tested with different bioassay materials.In conidial bioassay,V-3 showed maximum aphid mortality?95%?and V-5 showed the lowest mortality?70%?at the highest concentration?1×10⁸ conidia/ml?at 8^th-day post-treatment whereas,in filtrate bioassay,98%mortality was achieved in V-3,and recorded mortality up-to 74%in V-5.Similarly,in the binary combination of fungal conidia 1×10⁸ conidia per ml and its filtrate,combination?V-3×V-3?revealed the highest M.persicae mortality 91%.The results revealed that V-3 isolate had the most virulent and its filtrate application is the most effective against M.persicae.?2?Different concentrations of partially purified protein,viz;0,2,4 and 6 mg mL^-1,with 10 replications for each treatment was used for bioassay.The results indicated the all protein concentrations could induce resistance to survivorship and fecundity of M.persicae.The highest concentration(6 mg mL^-1)showed minimum aphid survival?46%?at 7^th-day post-treatment.Similarly,minimum and maximum mean fecundity rates were recorded for the highest protein concentration and control(i.e.1.5 and 2.4 nymphs day^-1 female^-1,respectively).Gene expression analyses revealed that partially purified protein of L.lecanii strongly upregulated the SA associated genes?i.e.PR1,BGL2 and PAL?and moderately upregulated the JA associated genes?i.e.LOX,AOS and AOC?in tomato plants as compared to the control plants.Collectively,these findings demonstrate that the partially purified elicitor protein extracted from L.lecanii induced resistance against M.persicae in tomato plants,suggesting the L.lecanii elicitor protein maybe act as potential biological pest management tool against aphids and other sap-feeding pests.?3?The recombinant protein chit1 was purified by a His-Trap HP column and tested for activity against Galleria mellonella larvae by directly injecting in to the haemocoel with different protein concentration?200,250,300,350,400,450 and 500?g/ml?.The bioassay result showed that purified chit1 protein killed G.mellonella larvae effectively and mortality percentage depends on protein concentrations.The highest concentration revealed 95%mortality after 7 days.Thus,the results revealed that fungal protein can be used as an effective biological tool for the management of pests.