Pathogenicity and other characteristics of the endophytic Beauveria bassiana strain (Bals.) (Hypocreales: Cordycipitaceae)

Abstract

BackgroundAgriculture crops such as tomatoes and wheat are frequently targeted by insect pests which have a significant negative impact on the agricultural economies. The deployment of entomopathogenic fungi (EPF) for the control of the insect pests is an important alternative to synthetic insecticides. The EPF, Beauveria bassiana (Balsamo) Vuillemin, has been reported widely as a suitable biological control agent of many agricultural pests.ResultsIn this study, B. bassiana SS-1 was isolated from local plant crops and its pathogenicity was assessed against the greater wax moth larvae Galleria mellonella (L.). The development of the pathogenic B. bassiana SS-1 on the insect was visualized using scanning electron microscopy (SEM). Results showed the ability of B. bassiana SS-1 to secrete extracellularly the important enzymes essential for insect cuticle penetration. B. bassiana SS1 recorded the maximum mean lipase (5.3 U/ml), protease (32.13 U/ml), and chitinase activities (2.95 U/ml). The endophytic pathogenic fungus B. bassiana SS-1 demonstrated pathogenicity against the fourth instar larvae of G. mellonella showing LC50 at 2.47 × 102 conidia/ml and LC95 at 3.98 × 105 conidia/ml. The SEM results showed physical contact with B. bassiana SS-1 hyphae on the surface of the G. mellonella larvae. Thus, the isolated EPF B. bassiana SS-1, even endophytic, could be a promising biocontrol agent to manage agricultural insect pests.ConclusionThis study provided a comprehensive characterization of the pathogenicity of B. bassiana SS-1 with its microbiological characteristics. Future studies are needed to focus on the detection of highly virulent isolates against different insect pests and to assess their field contribution as a favorable biological control agent.