Cellular Immune Reactions of the Sunn Pest,Eurygaster integriceps, to the Entomopathogenic Fungus,Beauveria bassianaand Its Secondary Metabolites

Abstract

In this study, five morphological types of circulating hemocytes were recognized in the hemolymph of the adult sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), namely prohemocytes, plasmatocytes, granulocytes, adipohemocytes, and oenocytoids. The effects of the secondary metabolites of the entomopathogenic fungus Beauveria bassiana on cellular immune defenses of Eurygaster integriceps were investigated. The results showed that the fungal secondary metabolites inhibited phagocytic activity of E. integriceps hemocytes and hampered nodule formation. A reduction of phenoloxidase activity was also observed. The data suggest that B. bassiana produce secondary metabolites that disable several immune mechanisms allowing the fungus to overcome and then kill its host. This characteristic makes B. bassiana a promising model for biological control of insect pests such as E. integriceps.

Bioefficacy of Alpinia galanga (Zingiberaceae) Rhizome Extracts, (<I>E</I>)<I>-p</I>-Acetoxycinnamyl Alcohol, and (<I>E</I>)<I>-p</I>-Coumaryl Alcohol Ethyl Ether Against Bactrocera dorsalis (Diptera: Tephritidae) and the Impact on Detoxification Enzyme Activities

“…In contrast to the effects of fungal conidia (Lopes et al 2011;Sabry et al 2011;Khalid et al 2012;Nussenbaum et al 2012), researchers have paid more attention to the role of fungal secondary metabolites on host insects in recent years (Sokolova et al 1999;Xia et al 2000;Xia et al 2001;Zibaee et al 2009a;Zibaee et al 2011). Abdul-Wahid et al (2012) reported the pathogenicity of both a spore suspension and metabolite solution of two fungi, Trichoderma harzianum and Fusarium solani, against cockroaches (Periplaneta americana).…”

“…Zibaee et al (2011) suggested that the secondary metabolites produced by B. bassiana disable several immune mechanisms of Eurygaster integriceps, thus helping the fungus to overcome and kill its host. As the enzymatic defense in insects, detoxification enzymes play significant roles in eliminating exotic compounds and maintaining normal physiological functions (Li et al 2007).…”

Cellular immune response of the Asian corn borer, Ostrinia furnacalis (Lepidoptera: Pyralidae), to infection by the entomopathogenic fungus, Beauveria bassiana

“…Upon the inoculation of B. bassiana conidia, haemocytes were recruited for cell-mediated immune reactions such as nodulation, which resulted in the depletion of free circulating haemocytes in the haemolymph. Total haemocyte count losses have also been reported following treatment of Reticulitermes fl avipes with Metarhizium anisopliae, or the shield bug, Eurygaster integriceps Puton (Hemiptera: Scutelleridae) with B. bassiana and its secondary metabolites (Chouvenc et al, 2009;Zibaee et al, 2011). However, the challenge of Oncopeltus fasciatus with Phytomonas serpens induced a signifi cant increase in haemocyte count (Alves e Silva et al, 2013).…”

“…Nodule formation is initiated with the microaggregation of haemocytes, which then leads to the entrapment of large numbers of microorganisms in an extracellular material and ends with the melanization of mature nodules (Lavine & Strand, 2002;Franssens et al, 2006;Zibaee et al, 2011). After Asian corn borer larvae were infected by B. bassiana conidia, nodular structures containing conidia were observed in collected haemolymph (Fig.…”

Evaluating the Efficiency of the Entomopathogenic Fungus Beauveria bassiana to Control the Brown Banded Cockroach Supella longipalpa F.

“…It is known that certain secondary metabolites of entomopathogenic fungi, including destruxins, cyclosporine, and beauverolides, possess functions in impairing the immune response of the host insect, causing death [27]. [28] suggested that the secondary metabolites produced by B. bassiana disable several immune mechanisms of Eurygaster integriceps, thus helping the fungus to overcome and kill its host, as the enzymatic defense in insects, detoxification enzymes play significant roles in eliminating exotic. Table ( 4) indicates the presence of a significant difference in the mortality rate for each stage of the S. longipalpa and to periods after exposure and there are also significant differences between the stages for each of the periods after exposure separately.…”