Stimulation of <i>Fusarium graminearum</i> by maize pollen

Naik, D. M.; Busch, L. V.

doi:10.1139/b78-124

Cited by 17 publications

(8 citation statements)

References 6 publications

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“…The compounds responsible for this stimulatory activity were later identified as betaine and choline (Strange et al 1974). A similar response of F. graminearum to maize pollen was reported by Naik and Busch (1978), and Pugh et al (1933) also observed greater infection in the presence of anthers. In contrast, Engle et al (2002) did not observe significant stimulation of fungal growth in the presence of purified betaine or choline, nor in the presence of anther extracts.…”

Section: Germination and Initial Growth Of The Fungussupporting

confidence: 59%

Use of aFusarium graminearumstrain transformed with green fluorescent protein to study infection in wheat (Triticum aestivum)

Miller

Chabot

Ouellet

et al. 2004

Canadian Journal of Plant Pathology

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A strain of Fusarium graminearum, the predominant causal agent of fusarium head blight (FHB) in North America, which was transformed to constitutively express the green fluorescent protein (GFP) from jellyfish, was used to perform a comparative study of the early events of colonization in wheat between FHB-susceptible ('Roblin') and FHB-resistant ('Sumai 3') cultivars. Greenhouse grown plants from both cultivars were point inoculated at anthesis with a spore suspension of GFP-Fusarium, then maintained under intermittent misting conditions until harvest. Heads were harvested for microscopy at several points in timeduring the first 24 h after inoculation and, subsequently, at longer intervals, up to 21 days after inoculation. Infected material was visualized as whole mounts; in addition, tissue was fixed and cryosectioned to examine the progress of the fungus within the wheat tissues. In both 'Roblin' and 'Sumai 3', hyphae were visible inside the floret at the point of inoculation within a few hours of the inoculation. The fungus displayed a particular affinity for the pollen and anthers of both wheat cultivars. Fungal growth was most prolific on the ovaries and stigmas of both cultivars throughout the course of the infection. In general, only after the soft tissues of the ovaries and stigmas were thoroughly colonized, did the fungus begin to move into the rachis and to the exterior of the floret. The fungus was able to spread along the spike both internally, through the rachis, and across the external surfaces of the rachis and florets. The major difference in infection pattern between susceptible 'Roblin' and resistant 'Sumai 3' was that the spread of the fungus through the parenchyma and vascular tissues of the rachis was slower and less extensive in the latter. Résumé : Une souche de Fusarium graminearum, le principal agent responsable de la fusariose des panicules (FP) en Amérique du Nord, qui a été transformée pour exprimer de façon constitutive la protéine fluorescente verte (PFV) de méduse, a été utilisée dans une étude comparative des premiers évènements de la colonisation de cultivars de blé sensible à la FP ('Roblin') et résistant à la FP ('Sumai 3'). Des individus des deux cultivars cultivés en serre ont été inoculés à l'anthèse à l'aide d'une aiguille avec une suspension de spores de PFV-Fusarium, puis conservés dans des conditions de bruine intermittente jusqu'à la récolte. Des épis ont été récoltés pour examen microscopique à plusieurs moments au cours des 24 h qui ont suivi l'inoculation, puis à intervalles plus espacés jusqu'à 21 jours après l'inoculation. Le matériel infecté a été examiné dans son intégrité; de plus, après fixation des tissus, des cryosections on été visualisées afin d'étudier la progression du champignon à l'intérieur des tissus de blé. Tant pour 'Roblin' que pour 'Sumai 3', des hyphes étaient visibles à l'intérieur des fleurs, au point d'inoculation, au cours des quelques heures suivant l'inoculation. Le champignon a démontré une affinité particulière pour le pollen et les anthè...

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Section: Germination and Initial Growth Of The Fungussupporting

confidence: 59%

Use of aFusarium graminearumstrain transformed with green fluorescent protein to study infection in wheat (Triticum aestivum)

Miller

Chabot

Ouellet

et al. 2004

Canadian Journal of Plant Pathology

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“…4). The ability of compounds from maize pollen to stimulate the germination and growth of F. graminearum was demonstrated by Naik and Busch (1978), and the presence of pollen and (or) anthers has also been shown to stimulate growth of F. graminearum in wheat (Strange and Smith 1971;Miller et al 2004).…”

Section: In Vitro Experiments With Excised Earsmentioning

confidence: 99%

Colonization of maize silks by Fusarium graminearum, the causative organism of gibberella ear rot

2007

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One of the most economically important diseases of maize in Canada is gibberella ear rot caused by Fusarium graminearum Schwabe (teleomorph = Gibberella zeae (Schw.) Petch). Understanding how the fungus becomes established will help in developing effective strategies to reduce the incidence of this disease. This study investigates the infection process of F. graminearum on maize silks using both a wild-type F. graminearum as well as a strain transformed with a gene from jellyfish to constitutively express green fluorescent protein. Immature ears of maize were inoculated in the field with wild-type F. graminearum and harvested at specific times post infection, and the silks were stained with Chlorazol Black E for examination. In addition, uninoculated ears were excised, placed on water agar in large Petri dishes, and the silks inoculated with a suspension of macroconidia of the transformed fungus. The progress of fungal growth was then monitored using microscopy. Germination of conidia was observed 4-6 h after inoculation. A variable period of random growth often followed, after which some of the hyphae would grow in more or less straight lines down the silk towards the cob (rachis), and ultimately infect the developing kernels. Access to the cob occurred in 7-9 d in susceptible genotypes and 12-15 d in resistant genotypes. The fungus could penetrate the ovary directly through the silk attachment point or, when the silk was growing over other kernels, the fungus could traverse from the silk to colonize interkernel spaces. Entry into the cob was either through the rachis surface via exterior growth between kernels, or into the rachis via the pedicel.Résumé : Une des plus importantes maladies du maïs au Canada est la fusariose des épis, causée par le Fusarium graminearum Schwabe (teleomorph = Gibberella zeae (Schw.) Petch). Une compréhension du processus d'établissement du champignon aiderait à développer des stratégies efficaces pour réduire l'incidence de cette maladie. Les auteurs ont entrepris cette étude pour examiner le processus d'infection des barbes du maïs par le F. graminearum, en utilisant à la fois un type sauvage du F. graminearum et une souche transformée avec un gène de méduse, afin d'exprimer constitutivement une protéine verte fluorescente (GFP). Ils ont inoculé de jeunes épis de maïs, aux champs, avec le type sauvage, les ont récoltés périodiquement, et ont coloré les barbes au noir de chlorazol E. De plus, ils ont prélevé des épis non-inoculés, les ont placés sur eau gélosée dans de grands Petri et en ont inoculé les barbes avec une suspension de macroconidies du champignon transformé. Ils ont par la suite suivi la progression de la croissance fongique au microscope. On observe la germination des conidies 4-6 heures après l'inoculation. Une période variable de croissance aléatoire suit l'infection et, par après, certains des hyphes poussent en lignes plus ou moins droites dans la barbe vers l'épi (rachis), pour ultimement infecter le grain en formation. L'accès à l'épi survient après 7-9 jours ch...

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“…Much of the pollen shed from the tassels lodged in the axils of leaves subtending maturing cobs, and at tassel senescence many male flowers and other debris were trapped in this region. Naik & Busch (1978) reported that maize pollen stimulated infection of the leafaxils of maize plants by F. graminearum. Water was often seen trapped in the leafaxils and these regions have the potential to act as reservoirs of infection initially for the leaf, and later for the husk of the cob maturing in its axil.…”

Section: Leavesmentioning

confidence: 99%

Fusariuminfection in some Waikato maize

Sayer

1991

New Zealand Journal of Crop and Horticultural Science

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Stimulation of Fusarium graminearum by maize pollen

Cited by 17 publications

References 6 publications

Use of aFusarium graminearumstrain transformed with green fluorescent protein to study infection in wheat (Triticum aestivum)

Use of aFusarium graminearumstrain transformed with green fluorescent protein to study infection in wheat (Triticum aestivum)

Colonization of maize silks by Fusarium graminearum, the causative organism of gibberella ear rot

Fusariuminfection in some Waikato maize

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