Take-all decline in New Zealand wheat soils and the microorganisms associated with the potential mechanisms of disease suppression

Chng, Soonie; Cromey, M. G.; Dodd, Sarah Drakopoulou; Stewart, Alison; Butler, Ruth; Jaspers, Marlene V.

doi:10.1007/s11104-015-2620-4

Cited by 25 publications

(21 citation statements)

References 68 publications

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“…The bacterium is commonly isolated from New Zealand soils. The existence of TAD has been confirmed in some New Zealand soils, with Pseudomonads reported as one of the major microbial groups associated with it (Chng et al 2015).…”

Section: Introductionmentioning

confidence: 87%

“…This suggests that TAD could be developing in this field. The development of TAD soils are characterised by initially low take-all levels during the early cropping years, an outbreak of the disease between 2 and 7 years, and subsequently a decline of disease with increased yields (Chng et al 2015). Eight of these isolates showed 50% to 80% growth inhibition of Ggt ( Figure 5).…”

Section: Inhibition Of Gaeumannomyces Graminis Var Tritici By Pseudomentioning

confidence: 99%

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Functional characteristics of New Zealand wheat rhizosphere Pseudomonas fluorescens isolates and their potential to inhibit invitro growth of Gaeumannomyces graminis var tritici

Warren¹,

Chng²,

Butler³

2016

NZPP

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Pseudomonas fluorescens are soilinhabiting plant growthpromoting rhizobacteria (PGPR) linked with suppression of takeall of wheat a soilborne disease caused by Gaeumannomyces graminis var tritici (Ggt) PGPR increase plant growth by direct stimulation producing metabolites (such as 24diacetylphloroglucinol 24DAPG) to inhibit plant pathogens or by inducing host defence mechanisms Fortythree New Zealand P fluorescens isolates collected from wheat rhizospheres of different cropping histories were characterised for secondary metabolite production using biochemical assays and PCR analysis Their ability to inhibit the growth of Ggt was determined in dual plate assays All of the bacterial isolates produced siderophores and 10 isolates produced hydrogen cyanide (HCN) However none of the isolates produced indole acetic acid and the phlD gene responsible for the production of 24DAPG was not detected Isolates that showed at least 60 inhibition of Ggt growth were found to produce either HCN or high levels of siderophore The results suggest HCN and siderophores could play a role in suppressing Ggt and managing takeall in New Zealand

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Section: Introductionmentioning

confidence: 87%

Section: Inhibition Of Gaeumannomyces Graminis Var Tritici By Pseudomentioning

confidence: 99%

Functional characteristics of New Zealand wheat rhizosphere Pseudomonas fluorescens isolates and their potential to inhibit invitro growth of Gaeumannomyces graminis var tritici

Warren¹,

Chng²,

Butler³

2016

NZPP

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“…We investigated the influence of only two selected micro organisms commonly associated with Ggt. However, whole microbial community structures could be implicated in suppression of Ggt in New Zealand soils (Chng et al 2015) and hence affecting the interaction between Ggt and glyphosate. The influence of soil microorganism diversity, such as comparing natural and sterilised soil, and the influence of P. fluorescens strains on Ggt infection with glyphosate, should be investigated further.…”

Section: Treatmentmentioning

confidence: 99%

“…In New Zealand, the endophytic fungus Microdochium bolleyi co-occurs with Ggt regularly (Chng et al 2004) and is known overseas to potentially reduce take-all severity (Kirk & Deacon 1987). Pseudomonas fluorescens is also found regularly on wheat roots (Chng et al 2015) in New Zealand, and reported to antagonise Ggt and limit infection in fields grown with continuous wheat crops overseas (Kwak & Weller 2013). However, it is not known if these microorganisms influence take-all severity in wheat sown after application of glyphosate to weeds.…”

Section: Introductionmentioning

confidence: 99%

Influence of glyphosate herbicide treatment of couch grass on take-all caused by Gaeumannomyces graminis var. tritici with the addition of soil-borne microorganisms

Toor

Chng

Warren

et al. 2017

NZPP

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Couch grass rhizomes harbour Gaeumannomyces graminis var. tritici (Ggt), which causes take-all of wheat. Glyphosate used after cereal harvest to control couch can increase take- all in subsequent wheat crops. Following glyphosate treatment, the colonisation of senescing couch rhizomes by Ggt when treated with the endophytic fungus Microdochium bolleyi, and the spread of Ggt from senescing couch rhizomes to wheat when treated with the rhizobacterium Pseudomonas fluorescens, were investigated in two separate experiments. In Experiment 1, glyphosate increased Ggt inoculum in couch, irrespective of whether M. bolleyi was added to the potting medium. In Experiment 2, take-all severity and Ggt DNA concentration in roots of the accompanying wheat plants tended to decrease with glyphosate treatment of couch and increase only when P. fluorescens was added. Soil-borne microflora in fields containing glyphosate-sprayed couch may affect expression of take-all in subsequent wheat.

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“…Soils with specific disease suppression have been described worldwide (Cook and Rovira, 1976; Stutz et al, 1986; Weller et al, 2002; Lemanceau et al, 2006; Chng et al, 2015) and for diverse soilborne plant pathogens. They include soils suppressive to Gaeumannomyces graminis var.…”

Section: Introductionmentioning

confidence: 99%

Relationships between Root Pathogen Resistance, Abundance and Expression of Pseudomonas Antimicrobial Genes, and Soil Properties in Representative Swiss Agricultural Soils

et al. 2017

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Strains of Pseudomonas that produce antimicrobial metabolites and control soilborne plant diseases have often been isolated from soils defined as disease-suppressive, i.e., soils, in which specific plant pathogens are present, but plants show no or reduced disease symptoms. Moreover, it is assumed that pseudomonads producing antimicrobial compounds such as 2,4-diacetylphloroglucinol (DAPG) or phenazines (PHZ) contribute to the specific disease resistance of suppressive soils. However, pseudomonads producing antimicrobial metabolites are also present in soils that are conducive to disease. Currently, it is still unknown whether and to which extent the abundance of antimicrobials-producing pseudomonads is related to the general disease resistance of common agricultural soils. Moreover, virtually nothing is known about the conditions under which pseudomonads express antimicrobial genes in agricultural field soils. We present here results of the first side-by-side comparison of 10 representative Swiss agricultural soils with a cereal-oriented cropping history for (i) the resistance against two soilborne pathogens, (ii) the abundance of Pseudomonas bacteria harboring genes involved in the biosynthesis of the antimicrobials DAPG, PHZ, and pyrrolnitrin on roots of wheat, and (iii) the ability to support the expression of these genes on the roots. Our study revealed that the level of soil disease resistance strongly depends on the type of pathogen, e.g., soils that are highly resistant to Gaeumannomyces tritici often are highly susceptible to Pythium ultimum and vice versa. There was no significant correlation between the disease resistance of the soils, the abundance of Pseudomonas bacteria carrying DAPG, PHZ, and pyrrolnitrin biosynthetic genes, and the ability of the soils to support the expression of the antimicrobial genes. Correlation analyses indicated that certain soil factors such as silt, clay, and some macro- and micronutrients influence both the abundance and the expression of the antimicrobial genes. Taken together, the results of this study suggests that pseudomonads producing DAPG, PHZ, or pyrrolnitrin are present and abundant in Swiss agricultural soils and that the soils support the expression of the respective biosynthetic genes in these bacteria to various degrees. The precise role that these pseudomonads play in the general disease resistance of the investigated agricultural soils remains elusive.

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Take-all decline in New Zealand wheat soils and the microorganisms associated with the potential mechanisms of disease suppression

Cited by 25 publications

References 68 publications

Functional characteristics of New Zealand wheat rhizosphere <i>Pseudomonas fluorescens</i> isolates and their potential to inhibit invitro growth of <i>Gaeumannomyces graminis</i> var <i>tritici</i>

Functional characteristics of New Zealand wheat rhizosphere <i>Pseudomonas fluorescens</i> isolates and their potential to inhibit invitro growth of <i>Gaeumannomyces graminis</i> var <i>tritici</i>

Influence of glyphosate herbicide treatment of couch grass on take-all caused by <i>Gaeumannomyces graminis</i> var. <i>tritici</i> with the addition of soil-borne microorganisms

Relationships between Root Pathogen Resistance, Abundance and Expression of Pseudomonas Antimicrobial Genes, and Soil Properties in Representative Swiss Agricultural Soils

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