The pericarp and its surface wax layer in maize kernels as resistance factors to fumonisin accumulation by Fusarium verticillioides

ABSTRACT Fumonisins are a group of mycotoxins that contaminate maize and cause leukoencephalomalacia in equine, pulmonary edema in swine, and promote cancer in mice. Fumonisin biosynthesis in Fusarium verticillioides is repressed by nitrogen and alkaline pH. We cloned a PACC-like gene (PAC1) from F. verticillioides. PACC genes encode the major transcriptional regulators of several pH-responsive pathways in other filamentous fungi. In Northern blot analyses, a PAC1 probe hybridized to a 2.2-kb transcript present in F. verticillioides grown at alkaline pH. A mutant of F. verticillioides with a disrupted PAC1 gene had severely impaired growth at alkaline pH. The mutant produced more fumonisin than the wild type when grown on maize kernels and in a synthetic medium buffered at an acidic pH, 4.5. The mutant, but not the wild type, also produced fumonisin B1 when mycelia were resuspended in medium buffered at an alkaline pH, 8.4. Transcription of FUM1, a gene involved in fumonisin biosynthesis, was correlated with fumonisin production. We conclude that PAC1 is required for growth at alkaline pH and that Pac1 may have a role as a repressor of fumonisin biosynthesis under alkaline conditions.

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Volatile organic compounds from the interaction between Fusarium verticillioides and maize kernels as a natural repellents of Sitophilus zeamais

Journal of Stored Products Research ◽

10.1016/j.jspr.2017.08.001 ◽

2017 ◽

Vol 73 ◽

pp. 109-114 ◽

Cited By ~ 4

Author(s):

Virginia L. Usseglio ◽

Romina P. Pizzolitto ◽

Carolina Rodriguez ◽

María P. Zunino ◽

Julio A. Zygadlo ◽

...

Keyword(s):

Volatile Organic Compounds ◽

Organic Compounds ◽

Fusarium Verticillioides ◽

Sitophilus Zeamais ◽

Volatile Organic ◽

Maize Kernels

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Functional Characterization of fst1 in Fusarium verticillioides During Colonization of Maize Kernels

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-03-10-0074 ◽

2011 ◽

Vol 24 (1) ◽

pp. 18-24 ◽

Cited By ~ 19

Author(s):

Hun Kim ◽

Charles P. Woloshuk

Keyword(s):

Fusarium Verticillioides ◽

Functional Characterization ◽

Hexose Transporter ◽

Maize Endosperm ◽

Endosperm Tissue ◽

Genes Expression ◽

Fluorescent Tag ◽

Maize Kernels ◽

Delayed Growth

The putative hexose transporter gene fst1 in Fusarium verticillioides was identified previously by microarray analysis as a gene that was more highly expressed during colonization of autoclaved maize endosperm than germ. In contrast to a previous study, in which disruption of fst1 did not affect growth of the pathogen on autoclaved maize kernels, in the current study, we demonstrated that disruption of fst1 delayed growth and symptom development on wounded maize ears. Characterization of the fst1 promoter revealed that regulation of fst1 expression was similar to that of fumonisin biosynthetic (fum) genes; expression was highest during growth on endosperm tissue and repressed by elevated concentrations of ammonium in the growth medium. With a fluorescent tag attached to FST1, the protein localized transiently to the periphery of the cells near the plasma membrane and in vacuole-like structures, suggesting that membrane-localized FST1 was internalized and degraded in vacuoles. Expression of fst1 in a yeast strain lacking hexose transporter genes did not complement the yeast mutation, suggesting that FST1 does not transport glucose, fructose, or mannose. The results indicate a functional role for FST1 in pathogenesis during the colonization of living kernels.

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Artificial inoculation methods for testing microorganisms as control agents of seed- and soil-borne Fusarium-seedling blight of maize

Journal of Plant Diseases and Protection ◽

10.1007/s41348-020-00350-w ◽

2020 ◽

Vol 127 (6) ◽

pp. 883-893

Author(s):

Eckhard Koch ◽

Petra Zink ◽

Tobias Pfeiffer ◽

Astrid von Galen ◽

Ada Linkies ◽

...

Keyword(s):

Fusarium Verticillioides ◽

Dry Weight ◽

The Other ◽

Biocontrol Agents ◽

Artificial Inoculation ◽

Seedling Blight ◽

Maize Silage ◽

Control Seed ◽

Fusarium Seedling Blight ◽

Maize Kernels

Abstract The study describes the development and employment of plant tests based on artificial inoculation of seeds or the potting substrate for evaluating the potential of microorganisms to control seedling blight of maize caused by seed- and soil-borne fusaria. Nine strains of Fusarium were isolated from maize kernels and identified morphologically and by molecular methods as belonging to the species Fusarium verticillioides, F. subglutinans, F. cerealis, F. poae and F. proliferatum. In order to determine pathogenicity, maize kernels were inoculated by immersion in suspensions of conidia of these isolates and sown in a pasteurized substrate in seed trays. Based on plant dry weight, the isolates of F. verticillioides and F. subglutinans were more pathogenic than the other isolates. Using an isolate of F. subglutinans, the efficacy of a set of 25 potential fungal and bacterial antagonists was assessed using inoculation of maize kernels by placement in mixtures of the pathogen and the antagonists. The results obtained with this methodology indicate the potential of a number of different microorganisms applied as seed treatments, including some reported previously as biocontrol agents, to control seed-borne seedling blight of maize. In order to develop a method for the testing of biocontrol agents against soil-borne attack, isolates of F. subglutinans, F. cerealis and F poae from maize kernels together with isolates of F. avenaceum, F. culmorum and F. graminearum originating from maize silage and wheat were used to artificially inoculate the potting substrate. The results showed large differences in pathogenicity, with the most aggressive isolates belonging to F. culmorum and F. graminearum.

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Comparative Histological and Transcriptional Analysis of Maize Kernels Infected with Aspergillus flavus and Fusarium verticillioides

Frontiers in Plant Science ◽

10.3389/fpls.2017.02075 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 7

Author(s):

Xiaomei Shu ◽

David P. Livingston ◽

Charles P. Woloshuk ◽

Gary A. Payne

Keyword(s):

Aspergillus Flavus ◽

Fusarium Verticillioides ◽

Transcriptional Analysis ◽

Maize Kernels

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Fungal Pathogens of Maize Gaining Free Passage Along the Silk Road

Pathogens ◽

10.3390/pathogens7040081 ◽

2018 ◽

Vol 7 (4) ◽

pp. 81 ◽

Cited By ~ 8

Author(s):

Michelle Thompson ◽

Manish Raizada

Keyword(s):

Climate Change ◽

Fungal Pathogen ◽

Fungal Pathogens ◽

Fusarium Verticillioides ◽

Ear Rot ◽

Time Intervals ◽

Protective Strategies ◽

Sperm Nuclei ◽

Maize Kernels ◽

The Silk Road

Silks are the long threads at the tips of maize ears onto which pollen land and sperm nuclei travel long distances to fertilize egg cells, giving rise to embryos and seeds; however fungal pathogens also use this route to invade developing grain, causing damaging ear rots with dangerous mycotoxins. This review highlights the importance of silks as the direct highways by which globally important fungal pathogens enter maize kernels. First, the most important silk-entering fungal pathogens in maize are reviewed, including Fusarium graminearum, Fusarium verticillioides, and Aspergillus flavus, and their mycotoxins. Next, we compare the different modes used by each fungal pathogen to invade the silks, including susceptible time intervals and the effects of pollination. Innate silk defences and current strategies to protect silks from ear rot pathogens are reviewed, and future protective strategies and silk-based research are proposed. There is a particular gap in knowledge of how to improve silk health and defences around the time of pollination, and a need for protective silk sprays or other technologies. It is hoped that this review will stimulate innovations in breeding, inputs, and techniques to help growers protect silks, which are expected to become more vulnerable to pathogens due to climate change.

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Quantization of total fumonisins produced by Fusarium verticillioides strains in some maize and sorghum genotypes by ELISA

Zbornik Matice srpske za prirodne nauke ◽

10.2298/zmspn1121061r ◽

2011 ◽

pp. 61-70

Author(s):

Vahid Rahdzu ◽

Marjam Parcamijan ◽

Tagi Feizbas ◽

Majid Zamani

Keyword(s):

Fusarium Species ◽

Block Design ◽

Fusarium Verticillioides ◽

Elisa Test ◽

Spore Suspension ◽

Ear Rot ◽

Significant Difference ◽

Sorghum Genotypes ◽

Sorghum Grain ◽

Maize Kernels

Fusarium verticillioides is one of the most prevalent Fusarium species on maize and sorghum, causing Fusarium ear rot and sorghum grain mold in warm and humid regions of Iran. The pathogen produces potent mycotoxins known as fumonisins. In order to determine mycotoxin (fumonisins) production on different maize and sorghum genotypes, a field trial was carried out based on a randomized complete block design with 10 treatments and three replications for each crop at Gorgan station in 2010. The ears of corn plants were inoculated by spore suspension of the mixture of some virulent F. verticillioides isolates using an ear inoculation method (Nail Punch). The sorghum panicles were also inoculated by spraying of spore suspension isolates at f lowering stage. All infected kernels were evaluated by ELISA kits (AgraQuant Fumonisin Kit; Romer Labs, Austria) for their total fumonisins production at the physiological maturing stage. All genotypes showed statistically significant difference in their fumonisin production in Gorgan. The results of fumonisins analysis obtained from ELISA test showed that lines 1 (Resistant) and 3 (Susceptible) with 2.4 ppm and 13.7 ppm had the least and highest amount of total fumonisins respectively among all maize genotypes. Also among all sorghum genotypes, genotypes 10 and 6 with 0.2 ppm and 4.8 ppm had the least and the highest amount of total fumonisins respectively. The results of this experiment demonstrated that fumonisin production level in maize kernels (maybe as maize kernels are the main host of this fungus) was significantly higher than sorghum kernels in Gorgan region.

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