Pathogenic Fungi Associated with Fusarium Foot Rot of Winter Wheat in the Semiarid &gt;Pacific Northwest

Smiley, Richard W.; Patterson, Lisa-Marie

doi:10.1094/pd-80-0944

Cited by 138 publications

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“…These bacteria are well adapted to the rhizosphere environment (for a recent review see reference 29), and they produce several antimicrobial substances that are involved in suppression of plant diseases (7). Many Fusarium species, including Fusarium culmorum, and the related organism Microdochium nivale are well-known and widespread fungal plant pathogens which can cause different diseases at various developmental stages of a crop (36,43). This fact and the risk of triggering increased mycotoxin production by use of fungicides make these fungi difficult to control (30,36).…”

mentioning

confidence: 99%

Low-Temperature Isolation of Disease-Suppressive Bacteria and Characterization of a Distinctive Group of Pseudomonads

Johansson

Wright

2003

Appl Environ Microbiol

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The influence of environmental factors during isolation on the composition of potential biocontrol isolates is largely unknown. Bacterial isolates that efficiently suppressed wheat seedling blight caused by Fusarium culmorum were found by isolating psychrotrophic, root-associated bacteria and by screening them in a bioassay that mimicked field conditions. The impact of individual isolation factors on the disease-suppressive index (DSI) of almost 600 isolates was analyzed. The bacteria originated from 135 samples from 62 sites in Sweden and Switzerland. The isolation factors that increased the probability of finding isolates with high DSIs were sampling from arable land, Swiss origin of samples, and origination of isolates from plants belonging to the family Brassicaceae. The colony morphology of the isolates was characterized and compared to DSIs, which led to identification of a uniform morphological group containing 57 highly disease-suppressive isolates. Isolates in this group were identified as Pseudomonas sp.; they were fluorescent on King's medium B and had characteristic crystalline structures in their colonies. These isolates were morphologically similar to seven strains that had previously been selected for suppression of barley net blotch caused by Drechslera teres. Members of this morphological group grow at 1.5°C and produce an antifungal polyketide (2,3-deepoxy-2,3-didehydrorhizoxin [DDR]). They have similar two-dimensional polyacrylamide gel electrophoresis protein profiles, phenotypic characteristics, and in vitro inhibition spectra of pathogens. In summary, in this paper we describe some isolation factors that are important for obtaining disease-suppressive bacteria in our system, and we describe a novel group of biocontrol pseudomonads.In biological control, microorganisms isolated from plants and soils are employed to protect crop plants from diseases. In cereals, seed-and soilborne fungal diseases are often suppressed by fluorescent pseudomonads (4,6,16,17,25). These bacteria are well adapted to the rhizosphere environment (for a recent review see reference 29), and they produce several antimicrobial substances that are involved in suppression of plant diseases (7). Many Fusarium species, including Fusarium culmorum, and the related organism Microdochium nivale are well-known and widespread fungal plant pathogens which can cause different diseases at various developmental stages of a crop (36,43). This fact and the risk of triggering increased mycotoxin production by use of fungicides make these fungi difficult to control (30, 36). However, since biological control often operates through several modes of action, it provides new possibilities to address these two issues (15,19,21,25).Screening systems that approximate field conditions are more likely to result in selection of effective biocontrol isolates (12,24,50). In the temperate regions of the world, one critical environmental factor is the low temperature during winter and early spring (12). Hökeberg and et al. (13) developed an isolation...

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mentioning

confidence: 99%

Low-Temperature Isolation of Disease-Suppressive Bacteria and Characterization of a Distinctive Group of Pseudomonads

Johansson

Wright

2003

Appl Environ Microbiol

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“…The fact that F. semitectum, F. reticulatum, F. equiseti, and F. acuminatum were the dominant species isolated from the drier Power County location is also consistent with previous observations from this county (Strausbaugh et al 2004). Some of the same species are known to be associated with cereal roots in the PNW (Smiley and Patterson 1996) and have been shown to be associated with root and crown infections (Fedel-Moen and Harris 1987;Strausbaugh et al 2004Strausbaugh et al , 2005. The importance of the role these Fusarium spp.…”

Section: Discussionmentioning

confidence: 99%

“…Cereal foot-, crown-, and (or) (Cook 1968;Cook et al 2002;Paulitz et al 2002;Smiley 1996;Smiley and Patterson 1996;Smiley et al 2005a). However, the pathogen responsible for crown and root rots can vary among sites in the PNW (Smiley et al 2005a).…”

Section: Introductionmentioning

confidence: 99%

Influence of subsoiling on direct-seeded cereals in southeastern Idaho

Strausbaugh

Windes

2006

Canadian Journal of Plant Pathology

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Abstract:The influence of shallow (20 cm deep) subsoil tillage on cereals planted with a no-till planter was investigated for 3 years at two locations in southeastern Idaho. Among Fusarium spp., F. culmorum was the primary fungus isolated from diffuse brown-black root lesions in the wetter location (Ririe), while F. semitectum, F. reticulatum, F. equiseti, and F. acuminatum were the dominant species isolated at the drier location (Arbon Valley). Increased yields resulting from methyl bromide fumigation indicated that biological factors were limiting the yield. However, subsoiling did not influence nematode populations or fungal root rots. The primary parasitic nematode found at both locations was Pratylenchus neglectus. Subsoiling had a tendency to increase soil moisture at depths between 61 and 90 cm, to increase organic matter, and to decrease nitrogen. Yield increased by 8% or more with subsoil tillage at both locations the first year. Yield increases were not significant in other years, when moisture was particularly limiting or abundant. Subsoiling may prove favorable for cereals planted in a soil-conservation tillage system, but the risk of fungal root rots may increase with such a practice. Additional study is warranted, as subsoil-tillage practices may increase yield and desirable soil parameters without compromising the benefits associated with cereal production in a soil-conservation tillage system. Key words: Fusarium spp., fusarium root rot, direct seeding, dryland, subsoiling, no till, zero tillage.Résumé : L'effet d'un sous-solage superficiel (20 cm de profondeur) sur des céréales plantées avec un planteur pour le semis direct a été étudié pendant 3 ans à deux sites du sud-est de l'Idaho. Parmi les espèces du Fusarium, le F. culmorum a été le principal champignon isolé de lésions racinaires floues brun noir au site le plus humide (Ririe), alors que les F. semitectum, F. reticulatum, F. equiseti et F. acuminatum ont été les espèces dominantes isolées du site le plus sec (vallée d'Arbon). Des augmentations de rendement résultant de fumigation au bromure de méthyle ont révélé que des facteurs biologiques limitaient les rendements. Par contre, le sous-solage n'a pas eu d'effet sur les populations de nématodes ou sur les pourritures racinaires fongiques. Le Pratylenchus neglectus fut le principal nématode parasite retrouvé aux deux sites. Le sous-solage avait tendance à augmenter la teneur en eau du sol aux profondeurs entre 61 et 90 cm, à augmenter la matière organique et à diminuer l'azote. Avec le sous-solage, les rendements ont augmenté de 8% ou plus aux deux sites au cours de la première année. Lors des autres années, les augmentations de rendement n'étaient pas significatives lorsque l'eau était particulièrement limitée ou abondante. Le sous-solage peut s'avérer profitable pour les céréales plantées dans un système de conservation des sols, mais une telle pratique pourrait accroître le risque de pourriture racinaire fongique. Des études supplémentaires sont souhaitables puisque les pratiques de so...

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“…When rates of nitrogen were backed off to match a realistic yield goal, fusarium root and crown rot caused by F. culmorum mostly disappeared, at least in fields planted to soft white winter wheats (8). As noted above, the disease has since become a problem for hard red (bread-type) wheats managed with nitrogen inputs for high grain protein, and the more pathogenic F. pseudograminearum has become more important (47), possibly due to wider use of conservation tillage practices (35).…”

Section: Setting a Course Focused On Cultural Practices Rather Than Gmentioning

confidence: 99%

Tell Me Again What It Is That You Do

Cook

2007

Annu. Rev. Phytopathol.

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My job at Pullman, Washington, starting in 1965, was to control the root diseases of wheat and barley, focusing first on fusarium root and crown rot, then including take-all and pythium and rhizoctonia root rots. In the absence of viable alternatives, the agronomic approaches used were implemented through design of cereal-based cropping systems. Starting in the late 1970s, the mission focused further on cereal-intensive direct-seed (no-till) cropping systems. A team effort demonstrated the role of indigenous antibiotic-producing fluorescent pseudomonads in the widespread decline of take-all in response to monoculture wheat (or barley-wheat sequences). Today, the suppression of take-all by these beneficial rhizobacteria is the centerpiece of an integrated system that augments take-all decline while limiting pythium and rhizoctonia root rots and fusarium root and crown rot in direct-seed systems. In such systems, "crop rotation" takes the form of different sequences of winter and spring wheat, barley and triticale varieties, and market classes, all susceptible to all four root diseases.

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Pathogenic Fungi Associated with Fusarium Foot Rot of Winter Wheat in the Semiarid >Pacific Northwest

Cited by 138 publications

References 0 publications

Low-Temperature Isolation of Disease-Suppressive Bacteria and Characterization of a Distinctive Group of Pseudomonads

Low-Temperature Isolation of Disease-Suppressive Bacteria and Characterization of a Distinctive Group of Pseudomonads

Influence of subsoiling on direct-seeded cereals in southeastern Idaho

Tell Me Again What It Is That You Do

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