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Abstract: Metarhizium anisopliae is an entomopathogenic fungus well characterized for the biocontrol of a wide range of plagues. Its pathogenicity depends on the secretion of hydrolytic enzymes that degrade the host cuticle. To identify proteins involved in the infection process and in host specify, immunoproteomic analysis was performed using antiserum produced against crude extract of M. anisopliae cultured in the presence of Rhipicephalus (Boophilus) microplus and Dysdercus peruvianus cuticles. Spots detected using antisera produced against M. anisopliae cultured in cuticles and spore surface proteins, but not with antiserum against M. anisopliae cultured in glucose, were identified so as to give insights about the infection process. An MS/MS allowed the identification of proteases, like elastase, trypsin, chymotrypsin, carboxypeptidase and subtilisin (Pr1A, Pr1I and PR1J), chitinases, DNase I and proline-rich protein. Chymotrypsin and Pr1I were inferred as host specific, being recognized in D. peruvianus infection only. This research represents an important contribution to the understanding the adaptation mechanisms of M. anisopliae to different hosts. [Copyright &y& Elsevier]

Abstract: Differential immunoproteomics was applied to identify proteins secreted by Metarhizium anisopliae induced by the Rhipicephalus microplus cuticle. In addition, IgG anti-spore surface proteins were used for searching for proteins possibly involved in early stages of fungus versus tick infection. LC-MS/MS of differentially secreted proteins led to the identification of proteases (carboxypeptidase and Pr1A), chitinase, carboxylic acid transport and proline-rich protein. Differential immunoproteomics strategy facilitated the detection and the identification of new proteins related to M. anisopliae host–pathogen interaction and could be used in further works to identify novel proteins related to other microbial infection systems. [Copyright &y& Elsevier]

Although Metarhizium anisopliae is one of the most studied fungal biocontrol agents, its infection mechanism is far from being completely understood. Using multidimensional protein identification technology (MudPIT), we evaluated the differential secretome of M. anisopliae E6 induced by the host Rhipicephalus microplus cuticle. The proteomic result showed changes in the expression of 194 proteins after exposure to host cuticle, such as proteins involved in adhesion, penetration, stress and fungal defense. Further, we performed a comparative genomic distribution of differentially expressed proteins of the M. anisopliae secretome against another arthropod pathogen, using the Beauveria bassiana ARSEF2860 protein repertory. Among 47 analyzed protein families, thirty were overexpressed in the M. anisopliae E6 predicted genome compared to B. bassiana. An in vivo toxicity assay using a Galleria mellonella model confirmed that the M. anisopliae E6 secretome was more toxic in cattle tick infections compared to other secretomes, including B. bassiana with cattle ticks and M. anisopliae E6 with the insect Dysdereus peruvianus , which our proteomic results had also suggested. These results help explain molecular aspects associated with host infection specificity due to genetic differences and gene expression control at the protein level in arthropod-pathogenic fungi. [ABSTRACT FROM AUTHOR]

The bovine tick, Rhipicephalus microplus , is the main ectoparasite of cattle and causes loss of billions of dollars worldwide in lost meat, milk, and leather production, as well as control expenses. In addition to systemically impacting the host during the parasitic act, this parasite is also an important disease vector. Traditionally, the main commercial control of the tick is achieved through application of chemical acaricides, which can leave residues in the meat and milk. Moreover, ticks can become resistant to these chemicals due to their massive and incorrect use. Many alternative methods have been tested including vaccines and natural products from plant origin. However, the efficacy of these treatments is variable and limited, especially when used alone. Arthropod-pathogenic fungi, such as Metarhizium anisopliae , are among the natural microbial agents with promising potential to be used alone or in association with other products, for example with chemical acaricides. This article discusses several aspects of bovine tick control related to the use of M. anisopliae , which is one of the most studied and viable alternative tools for effective tick control. Image 1 • Dozens of tested M. anisopliae isolates able to control the cattle tick. • Field and pen studies proved the biocontrol potential. • Alternative to chemical acaricides and to control multi-resistant tick strains. • Combined use with commercial chemical acaricides. • Tick control on pasture suitable for organic production. [ABSTRACT FROM AUTHOR]