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Volatiles Emitted from Maize Ears Simultaneously Infected with Two Fusarium Species Mirror the Most Competitive Fungal Pathogen

View Article: PubMed Central - PubMed

ABSTRACT

Along with barley and rice, maize provides staple food for more than half of the world population. Maize ears are regularly infected with fungal pathogens of the Fusarium genus, which, besides reducing yield, also taint grains with toxic metabolites. In an earlier work, we have shown that maize ears infection with single Fusarium strains was detectable through volatile sensing. In nature, infection most commonly occurs with more than a single fungal strain; hence we tested how the interactions of two strains would modulate volatile emission from infected ears. For this purpose, ears of a hybrid and a dwarf maize variety were simultaneously infected with different strains of Fusarium graminearum and F. verticillioides and, the resulting volatile profiles were compared to the ones of ears infected with single strains. Disease severity, fungal biomass, and the concentration of the oxylipin 9-hydroxy octadecadienoic acid, a signaling molecule involved in plant defense, were monitored and correlated to volatile profiles. Our results demonstrate that in simultaneous infections of hybrid and dwarf maize, the most competitive fungal strains had the largest influence on the volatile profile of infected ears. In both concurrent and single inoculations, volatile profiles reflected disease severity. Additionally, the data further indicate that dwarf maize and hybrid maize might emit common (i.e., sesquiterpenoids) and specific markers upon fungal infection. Overall this suggests that volatile profiles might be a good proxy for disease severity regardless of the fungal competition taking place in maize ears. With the appropriate sensitivity and reliability, volatile sensing thus appears as a promising tool for detecting fungal infection of maize ears under field conditions.

No MeSH data available.


Related in: MedlinePlus

Heatmap representing volatiles that are regulated in dwarf and hybrid maize upon infection with Fusarium. Squares correspond to the concentration of single volatiles emitted from independent ears for each treatment – dwarf maize, n = 5 replicates per treatment; hybrid maize, n = 4 replicates per treatment. Squares have been color coded to represent volatile concentrations (normalized from zero to one). The heatmap illustrates that volatiles are differentially regulated by single inoculations or co-inoculations of Fusarium strains. Treatments: Control, uninfected ears; FV, F. verticillioides; FG, F. graminearum. Refer to Table 1 for details about strain numbers. For hybrid maize, part of the data (control and single inoculations with FG1 and 2 and FV1 and 2) has already been described in Becker et al., 2014. The data is shown here for consistency with dwarf maize and for allowing the comparison to co-inoculations.
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Figure 5: Heatmap representing volatiles that are regulated in dwarf and hybrid maize upon infection with Fusarium. Squares correspond to the concentration of single volatiles emitted from independent ears for each treatment – dwarf maize, n = 5 replicates per treatment; hybrid maize, n = 4 replicates per treatment. Squares have been color coded to represent volatile concentrations (normalized from zero to one). The heatmap illustrates that volatiles are differentially regulated by single inoculations or co-inoculations of Fusarium strains. Treatments: Control, uninfected ears; FV, F. verticillioides; FG, F. graminearum. Refer to Table 1 for details about strain numbers. For hybrid maize, part of the data (control and single inoculations with FG1 and 2 and FV1 and 2) has already been described in Becker et al., 2014. The data is shown here for consistency with dwarf maize and for allowing the comparison to co-inoculations.

Mentions: Volatile profiles presented a quite important quantitative variability within replicates of the same treatment (independent ears infected with the same fungus) whereas a qualitative variability in volatile composition was observed upon infection of different Fusarium species. This can be seen in the heatmaps of Figure 5 that have been color coded to represent the concentration of infection biomarkers in dwarf and hybrid maize. As an example of qualitative variability, in both maize varieties, the volatile trichodiene was only detected from F. graminearum but never from F. verticillioides. In dwarf maize, hexan-1-ol was induced by FV3 (FV3 alone, FG3+FV3, FG4+FV3) compared to single inoculations with FG3 and FG4 (Figure 5).


Volatiles Emitted from Maize Ears Simultaneously Infected with Two Fusarium Species Mirror the Most Competitive Fungal Pathogen
Heatmap representing volatiles that are regulated in dwarf and hybrid maize upon infection with Fusarium. Squares correspond to the concentration of single volatiles emitted from independent ears for each treatment – dwarf maize, n = 5 replicates per treatment; hybrid maize, n = 4 replicates per treatment. Squares have been color coded to represent volatile concentrations (normalized from zero to one). The heatmap illustrates that volatiles are differentially regulated by single inoculations or co-inoculations of Fusarium strains. Treatments: Control, uninfected ears; FV, F. verticillioides; FG, F. graminearum. Refer to Table 1 for details about strain numbers. For hybrid maize, part of the data (control and single inoculations with FG1 and 2 and FV1 and 2) has already been described in Becker et al., 2014. The data is shown here for consistency with dwarf maize and for allowing the comparison to co-inoculations.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037238&req=5

Figure 5: Heatmap representing volatiles that are regulated in dwarf and hybrid maize upon infection with Fusarium. Squares correspond to the concentration of single volatiles emitted from independent ears for each treatment – dwarf maize, n = 5 replicates per treatment; hybrid maize, n = 4 replicates per treatment. Squares have been color coded to represent volatile concentrations (normalized from zero to one). The heatmap illustrates that volatiles are differentially regulated by single inoculations or co-inoculations of Fusarium strains. Treatments: Control, uninfected ears; FV, F. verticillioides; FG, F. graminearum. Refer to Table 1 for details about strain numbers. For hybrid maize, part of the data (control and single inoculations with FG1 and 2 and FV1 and 2) has already been described in Becker et al., 2014. The data is shown here for consistency with dwarf maize and for allowing the comparison to co-inoculations.
Mentions: Volatile profiles presented a quite important quantitative variability within replicates of the same treatment (independent ears infected with the same fungus) whereas a qualitative variability in volatile composition was observed upon infection of different Fusarium species. This can be seen in the heatmaps of Figure 5 that have been color coded to represent the concentration of infection biomarkers in dwarf and hybrid maize. As an example of qualitative variability, in both maize varieties, the volatile trichodiene was only detected from F. graminearum but never from F. verticillioides. In dwarf maize, hexan-1-ol was induced by FV3 (FV3 alone, FG3+FV3, FG4+FV3) compared to single inoculations with FG3 and FG4 (Figure 5).

View Article: PubMed Central - PubMed

ABSTRACT

Along with barley and rice, maize provides staple food for more than half of the world population. Maize ears are regularly infected with fungal pathogens of the Fusarium genus, which, besides reducing yield, also taint grains with toxic metabolites. In an earlier work, we have shown that maize ears infection with single Fusarium strains was detectable through volatile sensing. In nature, infection most commonly occurs with more than a single fungal strain; hence we tested how the interactions of two strains would modulate volatile emission from infected ears. For this purpose, ears of a hybrid and a dwarf maize variety were simultaneously infected with different strains of Fusarium graminearum and F. verticillioides and, the resulting volatile profiles were compared to the ones of ears infected with single strains. Disease severity, fungal biomass, and the concentration of the oxylipin 9-hydroxy octadecadienoic acid, a signaling molecule involved in plant defense, were monitored and correlated to volatile profiles. Our results demonstrate that in simultaneous infections of hybrid and dwarf maize, the most competitive fungal strains had the largest influence on the volatile profile of infected ears. In both concurrent and single inoculations, volatile profiles reflected disease severity. Additionally, the data further indicate that dwarf maize and hybrid maize might emit common (i.e., sesquiterpenoids) and specific markers upon fungal infection. Overall this suggests that volatile profiles might be a good proxy for disease severity regardless of the fungal competition taking place in maize ears. With the appropriate sensitivity and reliability, volatile sensing thus appears as a promising tool for detecting fungal infection of maize ears under field conditions.

No MeSH data available.


Related in: MedlinePlus