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Transcriptome profiling of the rice blast fungus during invasive plant infection and in vitro stresses.

Mathioni SM, Beló A, Rizzo CJ, Dean RA, Donofrio NM - BMC Genomics (2011)

Bottom Line: We identified 4,973 genes that were differentially expressed in at least one of the in planta and in vitro stress conditions when compared to fungal mycelia grown in complete medium, which was used as reference.Functional categorization of the 55 induced genes revealed that most were either related to carbon metabolism, membrane proteins, or were involved in oxidoreduction reactions.The 129 repressed genes showed putative roles in vesicle trafficking, signal transduction, nitrogen metabolism, or molecular transport.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA.

ABSTRACT

Background: Rice blast is the most threatening disease to cultivated rice. Magnaporthe oryzae, its causal agent, is likely to encounter environmental challenges during invasive growth in its host plants that require shifts in gene expression to establish a compatible interaction. Here, we tested the hypothesis that gene expression patterns during in planta invasive growth are similar to in vitro stress conditions, such as nutrient limitation, temperature up shift and oxidative stress, and determined which condition most closely mimicked that of in planta invasive growth. Gene expression data were collected from these in vitro experiments and compared to fungal gene expression during the invasive growth phase at 72 hours post-inoculation in compatible interactions on two grass hosts, rice and barley.

Results: We identified 4,973 genes that were differentially expressed in at least one of the in planta and in vitro stress conditions when compared to fungal mycelia grown in complete medium, which was used as reference. From those genes, 1,909 showed similar expression patterns between at least one of the in vitro stresses and rice and/or barley. Hierarchical clustering of these 1,909 genes showed three major clusters in which in planta conditions closely grouped with the nutrient starvation conditions. Out of these 1,909 genes, 55 genes and 129 genes were induced and repressed in all treatments, respectively. Functional categorization of the 55 induced genes revealed that most were either related to carbon metabolism, membrane proteins, or were involved in oxidoreduction reactions. The 129 repressed genes showed putative roles in vesicle trafficking, signal transduction, nitrogen metabolism, or molecular transport.

Conclusions: These findings suggest that M. oryzae is likely primarily coping with nutrient-limited environments at the invasive growth stage 72 hours post-inoculation, and not with oxidative or temperature stresses.

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Gene expression profiles of known pathogenicity genes in M. oryzae during in vitro and in planta treatments. Induction/repression of known pathogenicity genes in M. oryzae subjected to in vitro stresses (TS, PQ, MM, MM-C, and MM-N) or inoculated in rice (R) or barley (B) leaves. Literature reference for each gene: MAS3 (Mathioni and Donofrio, unpublished); MPG1 [45]; ACI1 [60]; CUT2 [47]MoFLP1[48]; T4HN reductase [61]; PTH11 [62]; SPM1 [7]; ATG7 [63]; MgAOX [64].
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Figure 4: Gene expression profiles of known pathogenicity genes in M. oryzae during in vitro and in planta treatments. Induction/repression of known pathogenicity genes in M. oryzae subjected to in vitro stresses (TS, PQ, MM, MM-C, and MM-N) or inoculated in rice (R) or barley (B) leaves. Literature reference for each gene: MAS3 (Mathioni and Donofrio, unpublished); MPG1 [45]; ACI1 [60]; CUT2 [47]MoFLP1[48]; T4HN reductase [61]; PTH11 [62]; SPM1 [7]; ATG7 [63]; MgAOX [64].

Mentions: We examined the data set for known pathogenicity genes. Given that we chose a time-point more indicative of invasive growth (72 hpi), we did not expect to find many genes solely associated with pre-penetration and penetration since these events are complete by 24 hpi. However, nine pathogenicity genes were identified with common expression profiles in rice or barley and at least one other condition (Figure 4). All of the genes, with the exception of the MgAOX gene (MGG_12936.6), which encodes an alternative oxidase and is only induced during the in vitro conditions, were induced in one or both plant hosts along with MM-C and/or MM-N. The expression profiles for MPG1 (MGG_10315.6) and SPM1 (MGG_03670.6) support their previous roles in both virulence and growth during nitrogen limitation [7,17]. CUT2 (MGG_09100.6) was the only pathogenicity gene that is uniquely induced during in planta growth in both rice and barley at 72 hpi.


Transcriptome profiling of the rice blast fungus during invasive plant infection and in vitro stresses.

Mathioni SM, Beló A, Rizzo CJ, Dean RA, Donofrio NM - BMC Genomics (2011)

Gene expression profiles of known pathogenicity genes in M. oryzae during in vitro and in planta treatments. Induction/repression of known pathogenicity genes in M. oryzae subjected to in vitro stresses (TS, PQ, MM, MM-C, and MM-N) or inoculated in rice (R) or barley (B) leaves. Literature reference for each gene: MAS3 (Mathioni and Donofrio, unpublished); MPG1 [45]; ACI1 [60]; CUT2 [47]MoFLP1[48]; T4HN reductase [61]; PTH11 [62]; SPM1 [7]; ATG7 [63]; MgAOX [64].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3037901&req=5

Figure 4: Gene expression profiles of known pathogenicity genes in M. oryzae during in vitro and in planta treatments. Induction/repression of known pathogenicity genes in M. oryzae subjected to in vitro stresses (TS, PQ, MM, MM-C, and MM-N) or inoculated in rice (R) or barley (B) leaves. Literature reference for each gene: MAS3 (Mathioni and Donofrio, unpublished); MPG1 [45]; ACI1 [60]; CUT2 [47]MoFLP1[48]; T4HN reductase [61]; PTH11 [62]; SPM1 [7]; ATG7 [63]; MgAOX [64].
Mentions: We examined the data set for known pathogenicity genes. Given that we chose a time-point more indicative of invasive growth (72 hpi), we did not expect to find many genes solely associated with pre-penetration and penetration since these events are complete by 24 hpi. However, nine pathogenicity genes were identified with common expression profiles in rice or barley and at least one other condition (Figure 4). All of the genes, with the exception of the MgAOX gene (MGG_12936.6), which encodes an alternative oxidase and is only induced during the in vitro conditions, were induced in one or both plant hosts along with MM-C and/or MM-N. The expression profiles for MPG1 (MGG_10315.6) and SPM1 (MGG_03670.6) support their previous roles in both virulence and growth during nitrogen limitation [7,17]. CUT2 (MGG_09100.6) was the only pathogenicity gene that is uniquely induced during in planta growth in both rice and barley at 72 hpi.

Bottom Line: We identified 4,973 genes that were differentially expressed in at least one of the in planta and in vitro stress conditions when compared to fungal mycelia grown in complete medium, which was used as reference.Functional categorization of the 55 induced genes revealed that most were either related to carbon metabolism, membrane proteins, or were involved in oxidoreduction reactions.The 129 repressed genes showed putative roles in vesicle trafficking, signal transduction, nitrogen metabolism, or molecular transport.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Plant and Soil Sciences, University of Delaware, Newark, DE, USA.

ABSTRACT

Background: Rice blast is the most threatening disease to cultivated rice. Magnaporthe oryzae, its causal agent, is likely to encounter environmental challenges during invasive growth in its host plants that require shifts in gene expression to establish a compatible interaction. Here, we tested the hypothesis that gene expression patterns during in planta invasive growth are similar to in vitro stress conditions, such as nutrient limitation, temperature up shift and oxidative stress, and determined which condition most closely mimicked that of in planta invasive growth. Gene expression data were collected from these in vitro experiments and compared to fungal gene expression during the invasive growth phase at 72 hours post-inoculation in compatible interactions on two grass hosts, rice and barley.

Results: We identified 4,973 genes that were differentially expressed in at least one of the in planta and in vitro stress conditions when compared to fungal mycelia grown in complete medium, which was used as reference. From those genes, 1,909 showed similar expression patterns between at least one of the in vitro stresses and rice and/or barley. Hierarchical clustering of these 1,909 genes showed three major clusters in which in planta conditions closely grouped with the nutrient starvation conditions. Out of these 1,909 genes, 55 genes and 129 genes were induced and repressed in all treatments, respectively. Functional categorization of the 55 induced genes revealed that most were either related to carbon metabolism, membrane proteins, or were involved in oxidoreduction reactions. The 129 repressed genes showed putative roles in vesicle trafficking, signal transduction, nitrogen metabolism, or molecular transport.

Conclusions: These findings suggest that M. oryzae is likely primarily coping with nutrient-limited environments at the invasive growth stage 72 hours post-inoculation, and not with oxidative or temperature stresses.

Show MeSH
Related in: MedlinePlus