Comparative studies on the infection and colonization of maize leaves by Fusarium graminearum, F. proliferatum and F. verticillioides
Comparative studies on the infection and colonization of maize leaves by Fusarium graminearum, F. proliferatum and F. verticillioides
Main document (8.1MB)Type of Scholarly Publication
DissertationDate of Exam
18.12.2013Date of Publication
01.09.2014Advisor
Dehne, Heinz-WilhelmCo-Referee
Léon, JensMetadata
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Abstract
Infection of Fusarium species causes quantitative along with qualitative damage on small grains and maize plants. This is due to leaf damage together with contamination by formation of different mycotoxins. Because the vegetative as well as the reproductive plant parts of maize are used especially for animal feed and can be affected, information about the infection process and damage of the entire plants needed further elucidation.
The infection and colonization of maize leaves by the most important three Fusarium species provided insights in a role of the spread of Fusarium species from the different leaves into the cobs. Using microbiological assessments maize plants inoculated by Fusarium at the growth stage (GS) 15 reached higher infection rates than those inoculated at GS 35. Higher spore concentration and increased relative humidity resulted in more intensive colonization. Light regimes had no effect on the infection of different cultivars by Fusarium. The colonization of lower leaves was higher than the infection of upper leaves.
The lesion development of maize plants infected by Fusarium occurred especially on the immature leaves. Disease severity showed no difference among three species. Colonization was higher on symptom leaves than on symptomless leaves, but nevertheless even symptomless infections resulted in further propagation. Disease symptoms appeared on leaves inoculated by F. graminearum 4-5 days after inoculation (dai) and by F. proliferatum and F. verticillioides 7-8 dai. F. graminearum caused small water-soaked lesions and the lesions turned into yellow spots. F. proliferatum and F. verticillioides caused necrotic lesions, small holes and streaks.
The germination of conidia of all Fusarium species was present at 12 hours after inoculation. The penetration of all three Fusarium species was quite similar: All species were able to penetrate into the tissue through cuticles, epidermal cells, trichomes, but also via stomata. Forming appressoria, infection cushions or direct penetration demonstrated the broad host tissue these species resembled a high potential leading to symptomatic as well as asymptomatic infections.
All pathogens showed intercellular and intracellular infection of epidermal and mesophyll cells. Additionally, F. graminearum hyphae were found in sclerenchyma cells, xylem and the phloem vessels of detached leaves. The superficial hyphae and re-emerging hyphae of the three species produced conidia. Especially, macroconidia of F. graminearum produced secondary macroconidia and F. proliferatum formed microconidia inside tissues and sporulated through stomata and trichomes.
According to quantitative fungal DNA the biomass of Fusarium species increased until the 5th dai but afterwards decreased from the 5th dai to the 20th dai and increased again until the 40th dai. Disease severity and fungal biomass, disease severity and colonization of the 6th and 7th leaves were significantly positive correlation at 10 dai and 40 dai, respectively.
The infection of maize leaves by the three Fusarium species and their sporulation indicated an inoculum contribution to cob and kernel infection which may lead to reduce yield, quality and increase in potential mycotoxin contamination on maize. Vergleichende Untersuchungen zur Infektion und Besiedlung von Maisblättern durch Fusarium graminearum, F. proliferatum und F. verticillioides
Infektionen von Fusarium Arten verursachen quantitative und qualitative Schäden an Getreide und Mais. Diese Beeinträchtigungen erfolgen durch Blatt‐ und Kolbenschäden, vor allem aber auch durch die Kontamination der Pflanzenteile mit sehr unterschiedlichen Mykotoxinen. Von Mais werden sowohl vegetative als auch reproduktive Pflanzenteile des Mais beslastet sein können und diese werden vor allem in Gänze in die Tiernahrung eingebracht werden. Daher galt es Informationen über den Blattbefall an Mais zu gewinnen und daher den Infektionsprozess und die Schadwirkung an Mais detailliert zu verfolgen.
Die Infektion und Besiedelung von Maisblättern wurde bezüglich der 3 bedeutendsten Fusarium‐Arten an Mais verfolgt und ergaben wesentliche Rückschlüsse über die Ausbreitung von Fusarium‐Arten an Maispflanzen von Blättern bis hin zum Kolben. Mit mikrobiologischen Erhebungen an Maisplanzen konnte nach Inokulationen geklärt werden, dass junge Maispflanzen (inokuliert im Stadium GS 15) deutlich anfälliger waren als im Stadium GS 35. Die Erhöhung der Inokulumdichte und eine erhöhte Luftfeuchte förderten die Blattinfektionen. Belichtungsbedingungen ließen keinen Einfluss auf die Infektionen erkennen. In allen Erhebungen waren die Befälle der unteren Blätter der Maispflanzen deutlich höher als die Infektionen der oberen Blätter.
Die Entwicklung von Läsionen auf durch Fusarium infizierten Maispflanzen trat vor allem auf den unreifen Blättern auf. Die Befallshäufigkeit und Befallsintensität zeigte keinen Unterschied zwischen den drei Arten. Auch wenn die Besiedelung auf Blättern mit Symptomausprägung höher war, führten auch die symptomlosen Infektionen zu einer weiteren Ausbreitung. Bei Fusarium graminearum traten die Symptome 4‐5 Tage nach der Inokulation, bei F. proliferatum und F. verticiolliodies 7‐8 Tage nach der Inokulation. F. graminearum verursachte Läsionen, die anfangs aussahen, wie Verbrennungen durch heißes Wasser und sich anschließend in gelbe Flecke verwandelten. F. proliferatum und F. verticilloides verursachten Nekrosen, die als kleine Löcher und Streifen erschienen.
Die Konidien aller Fusarium‐Arten keimten im Zeitraum von 12 Stunden nach der Inokulation. Alle 3 zu vergleichenden Arten wiesen ein ähnliches Infektionsverhalten auf: Alle Arten konnten direkt in das Wirtsgewebe eindringen, penetriert wurden Cuticulen, Epidermiszellen, Trichome – gelegentlich erfolgte auch eine Eindringung über Spaltöffnungen. Dabei werden von den Pathogenen Appressorien gebildet, zudem Infektionskissen – aber dennoch kamen stets auch direkte Infektionen vor. Dies bestätigt das besonders breite Infektionsvermögen der Fusarien. Vor allem wurden aber symptomatische und asymptomatische Infektionen beobachtet.
Alle Pathogene zeigten ein inter‐ und intrazelluläres Wachstum in Epidermis und Mesophyll der Blätter. Fusarium graminearum besiedelte auch Gefässgewebe – sowohl Xylem‐ als auch Phloemgewebe. Die oberflächlichen Hyphen sporulierten stets auf dem Blattgewebe. F. graminearum bildete sekundäre Makrokonidien. F. proliferatum bildete Mikrokonidien im Gewebe und sporulierte als ubiquitärer Pathogen durch Stomata und Trichome.
Mittels quantitativer PCR wurde die pilzliche Biomasse erfasst. Bis zum 5. Tag nach der Inokulation stieg der Gehalt an – die symptomlose Infektion – in der Nekrotisierungsphase sank der Pilzgehalt um anschließend in der saprophytischen Phase der Infektion wieder anzusteigen.
Die Infektion von Maispflanzen und insbesondere Blättern durch 3 repräsentative Fusarium Arten und deren Sporulation sogar auf symptomlosen Blättern belegt die Bedeutung latenter Infektionen für die Kolben‐ und Körnerinfektion – dies gilt es zu vermeiden, um Ertragsbeeinträchtigungen und Einschränkungen der Qualität des Erntegut zu reduzieren.
The infection and colonization of maize leaves by the most important three Fusarium species provided insights in a role of the spread of Fusarium species from the different leaves into the cobs. Using microbiological assessments maize plants inoculated by Fusarium at the growth stage (GS) 15 reached higher infection rates than those inoculated at GS 35. Higher spore concentration and increased relative humidity resulted in more intensive colonization. Light regimes had no effect on the infection of different cultivars by Fusarium. The colonization of lower leaves was higher than the infection of upper leaves.
The lesion development of maize plants infected by Fusarium occurred especially on the immature leaves. Disease severity showed no difference among three species. Colonization was higher on symptom leaves than on symptomless leaves, but nevertheless even symptomless infections resulted in further propagation. Disease symptoms appeared on leaves inoculated by F. graminearum 4-5 days after inoculation (dai) and by F. proliferatum and F. verticillioides 7-8 dai. F. graminearum caused small water-soaked lesions and the lesions turned into yellow spots. F. proliferatum and F. verticillioides caused necrotic lesions, small holes and streaks.
The germination of conidia of all Fusarium species was present at 12 hours after inoculation. The penetration of all three Fusarium species was quite similar: All species were able to penetrate into the tissue through cuticles, epidermal cells, trichomes, but also via stomata. Forming appressoria, infection cushions or direct penetration demonstrated the broad host tissue these species resembled a high potential leading to symptomatic as well as asymptomatic infections.
All pathogens showed intercellular and intracellular infection of epidermal and mesophyll cells. Additionally, F. graminearum hyphae were found in sclerenchyma cells, xylem and the phloem vessels of detached leaves. The superficial hyphae and re-emerging hyphae of the three species produced conidia. Especially, macroconidia of F. graminearum produced secondary macroconidia and F. proliferatum formed microconidia inside tissues and sporulated through stomata and trichomes.
According to quantitative fungal DNA the biomass of Fusarium species increased until the 5th dai but afterwards decreased from the 5th dai to the 20th dai and increased again until the 40th dai. Disease severity and fungal biomass, disease severity and colonization of the 6th and 7th leaves were significantly positive correlation at 10 dai and 40 dai, respectively.
The infection of maize leaves by the three Fusarium species and their sporulation indicated an inoculum contribution to cob and kernel infection which may lead to reduce yield, quality and increase in potential mycotoxin contamination on maize.
Infektionen von Fusarium Arten verursachen quantitative und qualitative Schäden an Getreide und Mais. Diese Beeinträchtigungen erfolgen durch Blatt‐ und Kolbenschäden, vor allem aber auch durch die Kontamination der Pflanzenteile mit sehr unterschiedlichen Mykotoxinen. Von Mais werden sowohl vegetative als auch reproduktive Pflanzenteile des Mais beslastet sein können und diese werden vor allem in Gänze in die Tiernahrung eingebracht werden. Daher galt es Informationen über den Blattbefall an Mais zu gewinnen und daher den Infektionsprozess und die Schadwirkung an Mais detailliert zu verfolgen.
Die Infektion und Besiedelung von Maisblättern wurde bezüglich der 3 bedeutendsten Fusarium‐Arten an Mais verfolgt und ergaben wesentliche Rückschlüsse über die Ausbreitung von Fusarium‐Arten an Maispflanzen von Blättern bis hin zum Kolben. Mit mikrobiologischen Erhebungen an Maisplanzen konnte nach Inokulationen geklärt werden, dass junge Maispflanzen (inokuliert im Stadium GS 15) deutlich anfälliger waren als im Stadium GS 35. Die Erhöhung der Inokulumdichte und eine erhöhte Luftfeuchte förderten die Blattinfektionen. Belichtungsbedingungen ließen keinen Einfluss auf die Infektionen erkennen. In allen Erhebungen waren die Befälle der unteren Blätter der Maispflanzen deutlich höher als die Infektionen der oberen Blätter.
Die Entwicklung von Läsionen auf durch Fusarium infizierten Maispflanzen trat vor allem auf den unreifen Blättern auf. Die Befallshäufigkeit und Befallsintensität zeigte keinen Unterschied zwischen den drei Arten. Auch wenn die Besiedelung auf Blättern mit Symptomausprägung höher war, führten auch die symptomlosen Infektionen zu einer weiteren Ausbreitung. Bei Fusarium graminearum traten die Symptome 4‐5 Tage nach der Inokulation, bei F. proliferatum und F. verticiolliodies 7‐8 Tage nach der Inokulation. F. graminearum verursachte Läsionen, die anfangs aussahen, wie Verbrennungen durch heißes Wasser und sich anschließend in gelbe Flecke verwandelten. F. proliferatum und F. verticilloides verursachten Nekrosen, die als kleine Löcher und Streifen erschienen.
Die Konidien aller Fusarium‐Arten keimten im Zeitraum von 12 Stunden nach der Inokulation. Alle 3 zu vergleichenden Arten wiesen ein ähnliches Infektionsverhalten auf: Alle Arten konnten direkt in das Wirtsgewebe eindringen, penetriert wurden Cuticulen, Epidermiszellen, Trichome – gelegentlich erfolgte auch eine Eindringung über Spaltöffnungen. Dabei werden von den Pathogenen Appressorien gebildet, zudem Infektionskissen – aber dennoch kamen stets auch direkte Infektionen vor. Dies bestätigt das besonders breite Infektionsvermögen der Fusarien. Vor allem wurden aber symptomatische und asymptomatische Infektionen beobachtet.
Alle Pathogene zeigten ein inter‐ und intrazelluläres Wachstum in Epidermis und Mesophyll der Blätter. Fusarium graminearum besiedelte auch Gefässgewebe – sowohl Xylem‐ als auch Phloemgewebe. Die oberflächlichen Hyphen sporulierten stets auf dem Blattgewebe. F. graminearum bildete sekundäre Makrokonidien. F. proliferatum bildete Mikrokonidien im Gewebe und sporulierte als ubiquitärer Pathogen durch Stomata und Trichome.
Mittels quantitativer PCR wurde die pilzliche Biomasse erfasst. Bis zum 5. Tag nach der Inokulation stieg der Gehalt an – die symptomlose Infektion – in der Nekrotisierungsphase sank der Pilzgehalt um anschließend in der saprophytischen Phase der Infektion wieder anzusteigen.
Die Infektion von Maispflanzen und insbesondere Blättern durch 3 repräsentative Fusarium Arten und deren Sporulation sogar auf symptomlosen Blättern belegt die Bedeutung latenter Infektionen für die Kolben‐ und Körnerinfektion – dies gilt es zu vermeiden, um Ertragsbeeinträchtigungen und Einschränkungen der Qualität des Erntegut zu reduzieren.
Subjects
Symptom, Sporulation, Fusariosen, Biomasse, PCR, Befallsniveau, fusarium, disease severity
Classification (DDC)
630 Landwirtschaft, VeterinärmedizinNguyen, Thi Thanh Xuan: Comparative studies on the infection and colonization of maize leaves by Fusarium graminearum, F. proliferatum and F. verticillioides. - Bonn, 2014. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-34708
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-34708
@phdthesis{handle:20.500.11811/5822,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-34708,
author = {{Thi Thanh Xuan Nguyen}},
title = {Comparative studies on the infection and colonization of maize leaves by Fusarium graminearum, F. proliferatum and F. verticillioides},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2014,
month = sep,
note = {Infection of Fusarium species causes quantitative along with qualitative damage on small grains and maize plants. This is due to leaf damage together with contamination by formation of different mycotoxins. Because the vegetative as well as the reproductive plant parts of maize are used especially for animal feed and can be affected, information about the infection process and damage of the entire plants needed further elucidation.
The infection and colonization of maize leaves by the most important three Fusarium species provided insights in a role of the spread of Fusarium species from the different leaves into the cobs. Using microbiological assessments maize plants inoculated by Fusarium at the growth stage (GS) 15 reached higher infection rates than those inoculated at GS 35. Higher spore concentration and increased relative humidity resulted in more intensive colonization. Light regimes had no effect on the infection of different cultivars by Fusarium. The colonization of lower leaves was higher than the infection of upper leaves.
The lesion development of maize plants infected by Fusarium occurred especially on the immature leaves. Disease severity showed no difference among three species. Colonization was higher on symptom leaves than on symptomless leaves, but nevertheless even symptomless infections resulted in further propagation. Disease symptoms appeared on leaves inoculated by F. graminearum 4-5 days after inoculation (dai) and by F. proliferatum and F. verticillioides 7-8 dai. F. graminearum caused small water-soaked lesions and the lesions turned into yellow spots. F. proliferatum and F. verticillioides caused necrotic lesions, small holes and streaks.
The germination of conidia of all Fusarium species was present at 12 hours after inoculation. The penetration of all three Fusarium species was quite similar: All species were able to penetrate into the tissue through cuticles, epidermal cells, trichomes, but also via stomata. Forming appressoria, infection cushions or direct penetration demonstrated the broad host tissue these species resembled a high potential leading to symptomatic as well as asymptomatic infections.
All pathogens showed intercellular and intracellular infection of epidermal and mesophyll cells. Additionally, F. graminearum hyphae were found in sclerenchyma cells, xylem and the phloem vessels of detached leaves. The superficial hyphae and re-emerging hyphae of the three species produced conidia. Especially, macroconidia of F. graminearum produced secondary macroconidia and F. proliferatum formed microconidia inside tissues and sporulated through stomata and trichomes.
According to quantitative fungal DNA the biomass of Fusarium species increased until the 5th dai but afterwards decreased from the 5th dai to the 20th dai and increased again until the 40th dai. Disease severity and fungal biomass, disease severity and colonization of the 6th and 7th leaves were significantly positive correlation at 10 dai and 40 dai, respectively.
The infection of maize leaves by the three Fusarium species and their sporulation indicated an inoculum contribution to cob and kernel infection which may lead to reduce yield, quality and increase in potential mycotoxin contamination on maize.},
url = {https://hdl.handle.net/20.500.11811/5822}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-34708,
author = {{Thi Thanh Xuan Nguyen}},
title = {Comparative studies on the infection and colonization of maize leaves by Fusarium graminearum, F. proliferatum and F. verticillioides},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2014,
month = sep,
note = {Infection of Fusarium species causes quantitative along with qualitative damage on small grains and maize plants. This is due to leaf damage together with contamination by formation of different mycotoxins. Because the vegetative as well as the reproductive plant parts of maize are used especially for animal feed and can be affected, information about the infection process and damage of the entire plants needed further elucidation.
The infection and colonization of maize leaves by the most important three Fusarium species provided insights in a role of the spread of Fusarium species from the different leaves into the cobs. Using microbiological assessments maize plants inoculated by Fusarium at the growth stage (GS) 15 reached higher infection rates than those inoculated at GS 35. Higher spore concentration and increased relative humidity resulted in more intensive colonization. Light regimes had no effect on the infection of different cultivars by Fusarium. The colonization of lower leaves was higher than the infection of upper leaves.
The lesion development of maize plants infected by Fusarium occurred especially on the immature leaves. Disease severity showed no difference among three species. Colonization was higher on symptom leaves than on symptomless leaves, but nevertheless even symptomless infections resulted in further propagation. Disease symptoms appeared on leaves inoculated by F. graminearum 4-5 days after inoculation (dai) and by F. proliferatum and F. verticillioides 7-8 dai. F. graminearum caused small water-soaked lesions and the lesions turned into yellow spots. F. proliferatum and F. verticillioides caused necrotic lesions, small holes and streaks.
The germination of conidia of all Fusarium species was present at 12 hours after inoculation. The penetration of all three Fusarium species was quite similar: All species were able to penetrate into the tissue through cuticles, epidermal cells, trichomes, but also via stomata. Forming appressoria, infection cushions or direct penetration demonstrated the broad host tissue these species resembled a high potential leading to symptomatic as well as asymptomatic infections.
All pathogens showed intercellular and intracellular infection of epidermal and mesophyll cells. Additionally, F. graminearum hyphae were found in sclerenchyma cells, xylem and the phloem vessels of detached leaves. The superficial hyphae and re-emerging hyphae of the three species produced conidia. Especially, macroconidia of F. graminearum produced secondary macroconidia and F. proliferatum formed microconidia inside tissues and sporulated through stomata and trichomes.
According to quantitative fungal DNA the biomass of Fusarium species increased until the 5th dai but afterwards decreased from the 5th dai to the 20th dai and increased again until the 40th dai. Disease severity and fungal biomass, disease severity and colonization of the 6th and 7th leaves were significantly positive correlation at 10 dai and 40 dai, respectively.
The infection of maize leaves by the three Fusarium species and their sporulation indicated an inoculum contribution to cob and kernel infection which may lead to reduce yield, quality and increase in potential mycotoxin contamination on maize.},
url = {https://hdl.handle.net/20.500.11811/5822}
}
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