Limits...
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

Structures of common and specific infection biomarkers in hybrid and dwarf maize. Color coder represent chemical classes: (1) (+)-longifolene, (2) β-farnesene, (3) β-macrocarpene, (4) trichodiene, (5) (+)-cycloisosativene, (6) α-ylangene, (7) (+)-aromadendrene, (8) α-selinene, (9) β-selinene, (10) 3-hexen-1-ol, (11) β-bisabolene, (12) heptan-2-ol, (13) 1-octen-3-ol, (14) octan-3-ol, (15) octan-3-one, (16) α-muurolene, (17) pentan-1-ol, (18) hexan-1-ol, (19) pentan-3-one, (20) 2-methyl-butanal, (21) pentane, (22) 3-methyl-butanal, (23) dimethyl sulfide.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5037238&req=5

Figure 4: Structures of common and specific infection biomarkers in hybrid and dwarf maize. Color coder represent chemical classes: (1) (+)-longifolene, (2) β-farnesene, (3) β-macrocarpene, (4) trichodiene, (5) (+)-cycloisosativene, (6) α-ylangene, (7) (+)-aromadendrene, (8) α-selinene, (9) β-selinene, (10) 3-hexen-1-ol, (11) β-bisabolene, (12) heptan-2-ol, (13) 1-octen-3-ol, (14) octan-3-ol, (15) octan-3-one, (16) α-muurolene, (17) pentan-1-ol, (18) hexan-1-ol, (19) pentan-3-one, (20) 2-methyl-butanal, (21) pentane, (22) 3-methyl-butanal, (23) dimethyl sulfide.

Mentions: Volatile compound identification was achieved using Kovats retention indices, mass spectral libraries, and authentic standards when available. VOC markers which concentration significantly differed between healthy and infected plants included an alkane, a sulfur compound, alcohols, ketones, and terpenoids and some unidentified compounds. From both maize varieties, 23 volatile markers could be identified or tentatively identified, 12 from dwarf and 15 from hybrid maize, and both varieties shared six common markers including; (+)-longifolene, β-farnesene, β-macrocarpene, trichodiene, and two unidentified SQT (Figures 3 and 4). The pie chart in Figure 3 illustrating the number of volatiles common and specific to both maize varieties includes unidentified volatiles in addition to the identified and tentatively identified ones listed in Figure 4. Differences in the volatile markers of both maize varieties could be ascribed to aldehydes, one alkane and a sulfur compound present in dwarf maize only whereas numerous sesquiterpenoids could solely be detected from hybrid maize (Figure 4).


Volatiles Emitted from Maize Ears Simultaneously Infected with Two Fusarium Species Mirror the Most Competitive Fungal Pathogen
Structures of common and specific infection biomarkers in hybrid and dwarf maize. Color coder represent chemical classes: (1) (+)-longifolene, (2) β-farnesene, (3) β-macrocarpene, (4) trichodiene, (5) (+)-cycloisosativene, (6) α-ylangene, (7) (+)-aromadendrene, (8) α-selinene, (9) β-selinene, (10) 3-hexen-1-ol, (11) β-bisabolene, (12) heptan-2-ol, (13) 1-octen-3-ol, (14) octan-3-ol, (15) octan-3-one, (16) α-muurolene, (17) pentan-1-ol, (18) hexan-1-ol, (19) pentan-3-one, (20) 2-methyl-butanal, (21) pentane, (22) 3-methyl-butanal, (23) dimethyl sulfide.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 4: Structures of common and specific infection biomarkers in hybrid and dwarf maize. Color coder represent chemical classes: (1) (+)-longifolene, (2) β-farnesene, (3) β-macrocarpene, (4) trichodiene, (5) (+)-cycloisosativene, (6) α-ylangene, (7) (+)-aromadendrene, (8) α-selinene, (9) β-selinene, (10) 3-hexen-1-ol, (11) β-bisabolene, (12) heptan-2-ol, (13) 1-octen-3-ol, (14) octan-3-ol, (15) octan-3-one, (16) α-muurolene, (17) pentan-1-ol, (18) hexan-1-ol, (19) pentan-3-one, (20) 2-methyl-butanal, (21) pentane, (22) 3-methyl-butanal, (23) dimethyl sulfide.
Mentions: Volatile compound identification was achieved using Kovats retention indices, mass spectral libraries, and authentic standards when available. VOC markers which concentration significantly differed between healthy and infected plants included an alkane, a sulfur compound, alcohols, ketones, and terpenoids and some unidentified compounds. From both maize varieties, 23 volatile markers could be identified or tentatively identified, 12 from dwarf and 15 from hybrid maize, and both varieties shared six common markers including; (+)-longifolene, β-farnesene, β-macrocarpene, trichodiene, and two unidentified SQT (Figures 3 and 4). The pie chart in Figure 3 illustrating the number of volatiles common and specific to both maize varieties includes unidentified volatiles in addition to the identified and tentatively identified ones listed in Figure 4. Differences in the volatile markers of both maize varieties could be ascribed to aldehydes, one alkane and a sulfur compound present in dwarf maize only whereas numerous sesquiterpenoids could solely be detected from hybrid maize (Figure 4).

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