Project description:Boreal toads (Anaxyrus boreas boreas) of the Southern Rocky Mountain population are declining due to the introduction of the chytrid fungus Batrachochytrium dendrobatidis (Bd). Boreal toads in Colorado are generally susceptible to Bd infection, but some Bd-tolerant populations persist in parts of the Southern Rocky Mountain and broader Eastern boreal toad population. We conducted a Bd challenge with lab-reared sibling toads from Bd-susceptible Colorado and purportedly Bd-tolerant Utah populations and report on transcriptomic responses to Bd during late infection in skin and liver tissue. Fewer immune genes were expressed in response to Bd in Colorado toads, but with greater upregulation compared to Utah toads, indicating a dysregulated immune response. Signatures of Bd-tolerance in Utah toads included more moderate upregulation in immune gene expression and a significantly enriched suite of gene functions related to innate and adaptive immune responses. Our transcriptomic results support the notion that Utah toads are tolerant to Bd, rather than resistant, carrying Bd loads similar to Colorado yet having a unique transcriptomic profile and presenting minimal clinical signs of chytridiomycosis. We conclude that closely related populations have divergent transcriptomic responses to Bd with a dysregulated immune response in Bd-susceptible toads.
Project description:Analysis of microbial community composition in arctic tundra and boreal forest soils using serial analysis of ribosomal sequence tags (SARST). Keywords: other
Project description:We report the discovery of a beta-glucosidase gene (Pgβglu-1) whose expression underpins natural resistance to a major forest pest, the spruce budworm (SBW) in white spruce (Picea glauca (Voss.) Moench). We performed a microarray experiment to compare resistant (R) and non-resistant (N-R) trees. Pgβglu-1 transcripts levels uniquely were up to 1000 times higher in phenotypically resistant trees and correlated with accumulation of acetophenones compounds that reduce SBW development. These resistance traits were heritable, temporally correlated with the emergence of the most damaging larval stages and were highly variable in the natural population across a large geographic area. The recombinant gene product specifically catalyzed the release of biologically active acetophenones from their glucoside precursors. SBW outbreaks have become more frequent and intense; therefore, the phenotypic diversity resulting from variation in Pgβglu-1 expression may be a key for the adaptability of spruce populations.
Project description:We report the discovery of a beta-glucosidase gene (PgM-NM-2glu-1) whose expression underpins natural resistance to a major forest pest, the spruce budworm (SBW) in white spruce (Picea glauca (Voss.) Moench). We performed a microarray experiment to compare resistant (R) and non-resistant (N-R) trees. PgM-NM-2glu-1 transcripts levels uniquely were up to 1000 times higher in phenotypically resistant trees and correlated with accumulation of acetophenones compounds that reduce SBW development. These resistance traits were heritable, temporally correlated with the emergence of the most damaging larval stages and were highly variable in the natural population across a large geographic area. The recombinant gene product specifically catalyzed the release of biologically active acetophenones from their glucoside precursors. SBW outbreaks have become more frequent and intense; therefore, the phenotypic diversity resulting from variation in PgM-NM-2glu-1 expression may be a key for the adaptability of spruce populations. Transcriptome profiling was carried out with needles from 7 resistant and 7 non-resistant trees (harvested on June 17th, 2010), and 3 samples per tree (n=42) with a custom microarray developed for spruce species and comprising oligonucleotide probes for 23,853 unique P. glauca gene sequences (Raherison et al., 2012).