Transcriptome and hormone profiling reveals Eucalyptus grandis defence responses against Chrysoporthe austroafricana
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Date
Authors
Mangwanda, Ronishree
Myburg, Alexander Andrew
Naidoo, Sanushka
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
BACKGROUND : Eucalyptus species and interspecific hybrids exhibit valuable growth and wood properties that make
them a highly desirable commodity. However, these trees are challenged by a wide array of biotic stresses during
their lifetimes. The Eucalyptus grandis reference genome sequence provides a resource to study pest and pathogen
defence mechanisms in long-lived woody plants. E. grandis trees are generally susceptible to Chrysoporthe austroafricana,
a causal agent of stem cankers on eucalypts. The aim of this study was to characterize the defence response of E. grandis
against C. austroafricana.
RESULTS : Hormone profiling of susceptible and moderately resistant clonal E. grandis genotypes indicated a reduction in
salicylic acid and gibberellic acid levels at 3 days post inoculation. We hypothesized that these signaling pathways may
facilitate resistance. To further investigate other defence mechanisms at this time point, transcriptome profiling was
performed. This revealed that cell wall modifications and response to oxidative stress form part of the defence responses
common to both genotypes, whilst changes in the hormone signaling pathways may contribute to resistance.
Additionally the expression of selected candidate defence response genes was induced earlier in moderately resistant
trees than in susceptible trees, supporting the hypothesis that a delayed defence response may occur in the susceptible
interaction.
CONCLUSION : The ability of a host to fine-tune its defence responses is crucial and the responses identified in this study
extends our understanding of plant defence, gained from model systems, to woody perennials.
Description
Additional file 1: Table S1. Summary of statistics obtained for
transcriptome profiling of TAG5 and ZG14 challenged with
C. austroafricana.
Additional file 2: Table S2. Summary of significantly differentially expressed genes and their annotations identified from Eucalyptus grandis TAG5 and ZG14.
Additional file 3: Figure S1. Molecular function GO terms that are over-represented in TAG5 and ZG14. a – GO terms within the upregulated dataset. b – GO terms within the down-regulated dataset (all terms for this dataset are shown). The y-axis represents the –log2(q-value) and the x-axis represents the GO terms within the datasets. Light and dark grey bars are ZG14 and TAG5 respectively.
Additional file 4: Figure S2. Cellular component GO terms that are over-represented in TAG5 and ZG14. a – GO terms within the upregulated dataset. b – GO terms within the down-regulated dataset. The y-axis represents the –log2(q-value) and the x-axis represents the GO terms within the datasets. Light and dark grey bars are ZG14 and TAG5 respectively.
Additional file 5: Table S3. List of differentially expressed genes that are common between the susceptible (ZG14) and moderately resistant (TAG5) host.
Additional file 2: Table S2. Summary of significantly differentially expressed genes and their annotations identified from Eucalyptus grandis TAG5 and ZG14.
Additional file 3: Figure S1. Molecular function GO terms that are over-represented in TAG5 and ZG14. a – GO terms within the upregulated dataset. b – GO terms within the down-regulated dataset (all terms for this dataset are shown). The y-axis represents the –log2(q-value) and the x-axis represents the GO terms within the datasets. Light and dark grey bars are ZG14 and TAG5 respectively.
Additional file 4: Figure S2. Cellular component GO terms that are over-represented in TAG5 and ZG14. a – GO terms within the upregulated dataset. b – GO terms within the down-regulated dataset. The y-axis represents the –log2(q-value) and the x-axis represents the GO terms within the datasets. Light and dark grey bars are ZG14 and TAG5 respectively.
Additional file 5: Table S3. List of differentially expressed genes that are common between the susceptible (ZG14) and moderately resistant (TAG5) host.
Keywords
Eucalyptus stem canker, Gibberellic acid, Hormone signalling, Plant defence, RNA-sequencing, Salicylic acid
Sustainable Development Goals
Citation
Mangwanda, R, Myburg, AA & Naidoo, S 2015, 'Transcriptome and hormone profiling reveals Eucalyptus grandis defence responses against Chrysoporthe austroafricana', BMC Genomics, vol. 16, no. 1, pp. 1-13.