Reconstructing the diversification of subtilisins in the pathogenic fungus Metarhizium anisopliae

Bagga, Savita; Hu, Gang; Screen, Steven E.; Leger, Raymond J. St.

doi:10.1016/j.gene.2003.09.031

Cited by 131 publications

(124 citation statements)

References 40 publications

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“…For genes encoding secreted products (hydrophobins, subtilisins, chitinases, etc. ), nucleotide identities between orthologs in Ma324 and Ma2575 range from 93% to 98%, with the most closely matching sequences at functional domains (3,17,37). The findings presented in this study reinforced these data, showing that ϳ6.7% of Ma2575 genes were absent or highly divergent in Ma324.…”

Section: Discussionsupporting

confidence: 83%

Comparative Genomics Using Microarrays Reveals Divergence and Loss of Virulence-Associated Genes in Host-Specific Strains of the Insect PathogenMetarhizium anisopliae

et al. 2009

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Many strains of Metarhizium anisopliae have broad host ranges, but others are specialists and adapted to particular hosts. Patterns of gene duplication, divergence, and deletion in three generalist and three specialist strains were investigated by heterologous hybridization of genomic DNA to genes from the generalist strain Ma2575. As expected, major life processes are highly conserved, presumably due to purifying selection. However, up to 7% of Ma2575 genes were highly divergent or absent in specialist strains. Many of these sequences are conserved in other fungal species, suggesting that there has been rapid evolution and loss in specialist Metarhizium genomes. Some poorly hybridizing genes in specialists were functionally coordinated, indicative of reductive evolution. These included several involved in toxin biosynthesis and sugar metabolism in root exudates, suggesting that specialists are losing genes required to live in alternative hosts or as saprophytes. Several components of mobile genetic elements were also highly divergent or lost in specialists. Exceptionally, the genome of the specialist cricket pathogen Ma443 contained extra insertion elements that might play a role in generating evolutionary novelty. This study throws light on the abundance of orphans in genomes, as 15% of orphan sequences were found to be rapidly evolving in the Ma2575 lineage.It is difficult to trace and reconstruct the evolutionary processes of diversification and radiation of species. In particular, genes that contribute to ecological diversification and the nature of the evolutionary forces acting during this process are poorly understood, partly because genes directly involved in ecological attributes are hard to identify (13). This is not the case with fungi, as they have genes encoding secreted products with specific environmental adaptations, e.g., scavenging nutrients and penetrating host barriers. During its pathogenic life cycle the ubiquitous insect pathogen Metarhizium anisopliae secretes a formidable array of hydrolytic enzymes, antimicrobial compounds, and toxins. These properties, plus its experimental tractability, have made M. anisopliae a common research subject and model system for studying pathogenicity and for developing useful products for medicine, agriculture, and biotechnology (33).The phylogeny of the Metarhizium genus has been well characterized (12). It is a largely clonal organism (4), containing subtypes with wide host ranges (e.g., M. anisopliae var. anisopliae Ma2575) and subtypes that, like M. anisopliae var. acridum Ma324 (used for locust control), show specificity for certain locusts, beetles, crickets, homopterans, etc., and are unable to infect other insects (5). While some specialized lineages, such as M. anisopliae var. acridum, are phylogenetically distant from generalist strains, implying evolutionarily conserved host use patterns, closely related strains can also differ greatly in host range and requirements for germination (16,40,42). Evidence that most specialists arose from generalis...

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Section: Discussionsupporting

confidence: 83%

Comparative Genomics Using Microarrays Reveals Divergence and Loss of Virulence-Associated Genes in Host-Specific Strains of the Insect PathogenMetarhizium anisopliae

et al. 2009

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“…Tandem duplication of Pr1 and expansion in subsets of subtilisin-like enzymes in pathogenic fungi may reflect adaptations to host ranges 75 while no comparable diversification of trypsin-like proteinases was found. The latter may confer only in those fungi selective functions that express them in high levels and possibly pre-adapt them to a parasitic life style.…”

Section: Coevolution Between Fungal Proteinases and Host Proteinase Imentioning

confidence: 93%

“…Indeed, all three proteinase types produced by M. anisopliae, the subtilisin-like serine proteinase Pr1, the trypsin-like serine proteinase Pr2, and the thermolysin-like metalloproteinase, occur in a variable number of isoforms which determine host range of different strains. 73,75,76 On the other hand we can predict loss or at least controlled expression of genes encoding secreted proteinases that are mostly inhibited by host molecules because the resources of bacterial or fungal pathogens are smaller than those of the infected host which has usually a remarkably higher biomass. Secretion of proteinases whose activities match that of host proteinase inhibitors would waste resources.…”

Section: Coevolution Between Fungal Proteinases and Host Proteinase Imentioning

confidence: 99%

Coevolution between pathogen-derived proteinases and proteinase inhibitors of host insects

Vilcinskas¹

2010

Virulence

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Virulence is thought to coevolve as a result of reciprocal selection between pathogens and their hosts. This paper focuses on coevolution between microbial proteinases operating as virulence factors and host defense molecules of insects. Owing to shorter generation times and smaller genomes, microbes exhibit a high evolutionary adaptability in comparison with their hosts. Indeed, the latter can only compete with pathogens if they evolve mechanisms providing a comparable genetic plasticity. Gene or domain duplication and shuffling by recombination is the driving force behind the countermeasures in host defense effectors. Recent literature provides evidence for both diversifications of fungal proteinases involved in pathogenesis and expansion host proteinase inhibitors subsets contributing to insect innate immunity. For example, the pathogen-associated spectrum of proteolytic enzymes encompasses thermolysin-like metalloproteinases that putatively promoted the evolution of corresponding host inhibitors of these virulence factors which complement the insect repertoire of antimicrobial defense molecules. Beyond mutual diversification of effector molecules coevolution resulted also in sophisticated molecular adaptations of host insects such as sensing and feedback-loop regulation of microbial metalloproteinases and corresponding countermeasures of pathogens providing evasion of host immunity induced by these virulence factors

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“…Recent studies based on the analysis of expressed sequence tag (EST) revealed the expression of several subtilisin-like proteases by M. anisopliae during growth on insect cuticle (FREIMOSER et al, 2003). These different subtilisins may play different roles in pathogenicity increasing the scale of adaptability to the host, or having different survival functions in several habitats under extreme ecological conditions (BAGGA et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Production of cuticle-degrading proteases by Nomuraea rileyi and its virulence against Anticarsia gemmatalis

et al. 2010

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Reconstructing the diversification of subtilisins in the pathogenic fungus Metarhizium anisopliae

Cited by 131 publications

References 40 publications

Comparative Genomics Using Microarrays Reveals Divergence and Loss of Virulence-Associated Genes in Host-Specific Strains of the Insect PathogenMetarhizium anisopliae

Comparative Genomics Using Microarrays Reveals Divergence and Loss of Virulence-Associated Genes in Host-Specific Strains of the Insect PathogenMetarhizium anisopliae

Coevolution between pathogen-derived proteinases and proteinase inhibitors of host insects

Production of cuticle-degrading proteases by Nomuraea rileyi and its virulence against Anticarsia gemmatalis

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