Pathozones of genetic subtypes of Gaeumannomyces graminis in cereals

Golldack, J.; Augustin, Claudia; Lentzsch, Peter; Werner, A.

doi:10.1016/j.soilbio.2003.08.025

Cited by 5 publications

(2 citation statements)

References 17 publications

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“…Other enzymes produced by Ggt are responsible for degradation of the components of plant cell walls (Annis and Goodwin, 1997). Defense plant reactions such as increased root production and increased root uptake of Ggt infected plants during early phase of the epidemic were also reported (Bailey and Gilligan, 2004;Golldack et al, 2004;Schoeny et al, 2003). As suggested by other studies on root-rotting diseases, all these factors may affect plant hormonal balance and may induce hormonal and wounding responses within the plant with a direct affect on leaf growth and possibly A (Kirkegaard et al, 1999).…”

Section: Discussionmentioning

confidence: 82%

The effect of take-all disease on gas-exchange rates and biomass in two winter wheat lines with different drought response

et al. 2005

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There have been no studies of the effect of take-all on leaf gas-exchange rates, despite the fact that take-all severely restricts plant water and nutrient uptake, which results in significant biomass and grain yield reduction. Here we describe the effect of inoculation with Gaeumannomyces graminis (Sacc.) var. tritici (Ggt) on carbon assimilation rate (A) and biomass production of wheat plants grown under two water regimes. We show that the impact of Ggt inoculation on plant growth and leaf A may be through reduced photosynthetic capacity of the leaves and not water stress per se. The nature of this reduced photosynthetic capacity remains uncertain but may involve nutrient deficiency and different enzymes produced by the fungus. In each of the 3 years the experiment was conducted, Ggt significantly reduced A, i.e. at anthesis by 18% in 2000, 15% in 2001, and 12% in 2002. In agreement with other field studies, Ggt reduced tiller number and production of all plant components, mostly root dry mass and grain mass per plant. Highly significant negative correlations were found between disease rating and A in all years, showing that at disease ratings equal or higher than 3 (on a scale from 1 to 4) A could practically be zero. While A decreased, intercellular CO 2 concentration increased or did not change, and stomatal conductance was relatively high. In addition, A was more reduced under high than under low soil moisture content. These results support the idea that water stress per se did not contribute to the observed reduction of A. The mechanism of photosynthetic capacity reduction due to the Ggt root-rotting fungus is of interest as it may lead to the molecular mechanisms of plant resistance and ultimately to the development of take-all resistant plants.

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Section: Discussionmentioning

confidence: 82%

The effect of take-all disease on gas-exchange rates and biomass in two winter wheat lines with different drought response

et al. 2005

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“…However, other properties can be considered in a similar way. For example, pathozone dynamics have been used to analyse the effects of antagonists (Bailey & Gilligan, 1997), host exudates (Figure 7) and genetic differences within pathogen species (Golldack et al ., 2004). Here we used the epidemiological approach to identify two processes operating at different spatial scales that drive soil‐borne epidemics, namely the spread of fungal colonies leading to infection of a single host, and invasive spread through a population of hosts.…”

Section: Discussionmentioning

confidence: 99%

Soil structure and soil‐borne diseases: using epidemiological concepts to scale from fungal spread to plant epidemics

Otten

Gilligan

2006

European J Soil Science

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SummaryMany epidemics of root diseases involving soil fungi depend on the interplay between fungal growth and the spatial and temporal heterogeneity of the soil environment. Colonization or infection of a root occurs at fine scales with growth and movement of fungal mycelia through soil. However, epidemics are observed at coarser scales, and depend on a cascading spread through populations of roots. We briefly review conventional analyses of soil-borne epidemics and argue that these treat soil physical conditions at scales too coarse to be meaningful for interactions between soil, plants and fungi, and fail to consider the effect of soil physical conditions on the underlying epidemiological processes. Instead, we propose a conceptual epidemiological framework that integrates spatial scales and use this to review the effect of soil structure on the dynamics of soil-borne pathogenic fungi. Using the soil-borne fungal plant pathogen Rhizoctonia solani as an example, we demonstrate that invasion of fungi into host populations is critically affected by environmental conditions operating at each of two scales: (i) at the microscopic scale (mm À cm) the fungus preferentially explores certain pathways in soil, and small changes in soil physical conditions make the fungus switch from small, dense colonies to large, sparse and rapidly expanding ones; (ii) at the larger scale (cm À dm) a critical density of susceptible hosts is required, in excess of which fungi switch from non-invasive to invasive spread. Finally, we suggest that the approach will increase the applicability of research dealing with microscopic soil-plant-microbe interactions towards the solution of large-scale epidemiological problems.

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Scaling from mycelial growth to infection dynamics: a reaction diffusion approach

Cunniffe

Gilligan

2008

Fungal Ecology

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Pathozones of genetic subtypes of Gaeumannomyces graminis in cereals

Cited by 5 publications

References 17 publications

The effect of take-all disease on gas-exchange rates and biomass in two winter wheat lines with different drought response

The effect of take-all disease on gas-exchange rates and biomass in two winter wheat lines with different drought response

Soil structure and soil‐borne diseases: using epidemiological concepts to scale from fungal spread to plant epidemics

Scaling from mycelial growth to infection dynamics: a reaction diffusion approach

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