Open AccessComparative Genomics Using Microarrays Reveals Divergence and Loss of Virulence-Associated Genes in Host-Specific Strains of the Insect PathogenMetarhizium anisopliae
Author(s) -
Sibao Wang,
Andreas Leclerque,
Monica PavaRipoll,
Weiguo Fang,
Raymond J. St. Leger
Publication year - 2009
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.00058-09
Subject(s) - biology , genome , gene , metarhizium anisopliae , comparative genomics , genetics , virulence , metarhizium , lineage (genetic) , horizontal gene transfer , genomics , gene family , host (biology) , conidium
Many strains ofMetarhizium 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 specialistMetarhizium 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.