Vertically transmitted fungal endophytes: different responses of host-parasite systems to environmental conditions

Oikos ◽  
2002 ◽  
Vol 99 (1) ◽  
pp. 173-183 ◽  
Author(s):  
Jouni U. Ahlholm ◽  
Marjo Helander ◽  
Silja Lehtimäki ◽  
Piippa Wäli ◽  
Kari Saikkonen
Keyword(s):  
Environmental Conditions ◽  
Fungal Endophytes ◽  
Host Parasite

Endoparasitism in colonial hosts: patterns and processes

Parasitology ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 841-852 ◽  
Author(s):  
S. L. L. HILL ◽  
B. OKAMURA
Keyword(s):  
Vertical Transmission ◽  
Environmental Conditions ◽  
Negative Effects ◽  
Temporal Sampling ◽  
Colony Fission ◽  
High Prevalence ◽  
Novel Host ◽  
Patterns And Processes ◽  
Host Parasite ◽  
Lack Of Knowledge

SUMMARYThis study begins to redress our lack of knowledge of the interactions between colonial hosts and their parasites by focusing on a novel host-parasite system. Investigations of freshwater bryozoan populations revealed that infection by myxozoan parasites is widespread. Covert infections were detected in all 5 populations studied and were often at high prevalence while overt infections were observed in only 1. Infections were persistent in populations subject to temporal sampling. Negative effects of infection were identified but virulence was low. Infection did not induce mortality in the environmental conditions studied. However, the production of statoblasts (dormant propagules) was greatly reduced in bryozoans with overt infections in comparison to uninfected bryozoans. Overtly-infected bryozoans also grew more slowly and had low fission rates relative to colonies lacking overt infection. Bryozoans with covert infections were smaller than uninfected bryozoans. High levels of vertical transmission were achieved through colony fission and the infection of statoblasts. Increased fission rates may be a strategy for hosts to escape from parasites but the parasite can also exploit the fragmentation of colonial hosts to gain vertical transmission and dispersal. Our study provides evidence that opportunities and constraints for host-parasite co-evolution can be highly dependent on organismal body plans and that low virulence may be associated with exploitation of colonial hosts by endoparasites.

Variation in the host-parasite relationship of a crop disease

1968 ◽  
Vol 71 (1) ◽  
pp. 19-36 ◽  
Author(s):  
M. H. Arnold ◽  
S. J. Brown
Keyword(s):  
Genetic Variation ◽  
Environmental Conditions ◽  
Phage Type ◽  
Resistance Breeding ◽  
Wide Range ◽  
Host Parasite Relationship ◽  
Parasite Relationship ◽  
Main Components ◽  
Host Parasite ◽  
Relationship Of

SummaryVariations in the host–parasite relationship of bacterial blight of cotton, caused by Xanthomonas malvacearum, E. F. Smith (Dowson), axe elucidated in terms of the three main components of variation, namely, genetic variation in the host, genetic variation in the parasite and variations in environment.Although the relative resistance shown by host varieties differed both with the culture of the pathogen used for inoculation and with the environmental conditions, over-riding patterns of host resistance could be detected, showing that certain varieties maintained their resistance over a wide range of conditions.It was found that phage type in X. malvacearum was not related to virulence. Moreover, none of the cultures of the pathogen which had been isolated from different sources, could be shown to be identical when inoculated into a range of host varieties under a range of environmental conditions. It was concluded that the pathogen showed continuous variation in virulence and that it would be difficult and of little value to attempt to define races.Some success was achieved in relating observed variations in the host–parasite relationship to easily measured components of the environment, by using multiple regression analyses. It is suggested that this might provide a means of characterizing the complex variations observed and that the host–parasite relationship could be regarded as a dynamic system, in which disease expression is a function of the interactions of environmental factors and two polygenic systems, that of the host and that of the parasite.Intrapopulation variances were also studied in the host varieties. A population which showed little variation for resistance under one set of conditions might show considerable variation in a different environment or when inoculated with a different culture. It is suggested that selection for resistance under conditions which favour the expression of variation can lead, by repeated selection and inbreeding, to the production of resistant populations which retain their resistance under conditions in which the parental stocks showed no worthwhile resistance. These conclusions are discussed in relation to problems in resistance breeding and genetics.

scholarly journals Fungi Inhabiting the Wheat Endosphere

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1288
Author(s):  
Błaszczyk Lidia ◽  
Salamon Sylwia ◽  
Mikołajczak Katarzyna
Keyword(s):  
Endophytic Fungi ◽  
Environmental Conditions ◽  
High Throughput Sequencing ◽  
Fungal Endophytes ◽  
Development Stage ◽  
Climatic Conditions ◽  
Experimental Conditions ◽  
Current State ◽  
Wheat Cultivation ◽  
Small Set

Wheat production is influenced by changing environmental conditions, including climatic conditions, which results in the changing composition of microorganisms interacting with this cereal. The group of these microorganisms includes not only endophytic fungi associated with the wheat endosphere, both pathogenic and symbiotic, but also those with yet unrecognized functions and consequences for wheat. This paper reviews the literature in the context of the general characteristics of endophytic fungi inhabiting the internal tissues of wheat. In addition, the importance of epigenetic regulation in wheat–fungus interactions is recognized and the current state of knowledge is demonstrated. The possibilities of using symbiotic endophytic fungi in modern agronomy and wheat cultivation are also proposed. The fact that the current understanding of fungal endophytes in wheat is based on a rather small set of experimental conditions, including wheat genotypes, plant organs, plant tissues, plant development stage, or environmental conditions, is recognized. In addition, most of the research to date has been based on culture-dependent methods that exclude biotrophic and slow-growing species and favor the detection of fast-growing fungi. Additionally, only a few reports of studies on the entire wheat microbiome using high-throughput sequencing techniques exist. Conducting comprehensive research on the mycobiome of the endosphere of wheat, mainly in the context of the possibility of using this knowledge to improve the methods of wheat management, mainly the productivity and health of this cereal, is needed.

scholarly journals Environmental Stress Determines The Colonization and Impact of An Endophytic Fungus On Invasive Knotweed

2021 ◽  
Author(s):  
Sigisfredo Garnica ◽  
Zhiyong Liao ◽  
Samuel Hamard ◽  
Frank Waller ◽  
Madalin Parepa ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Fine Roots ◽  
Immunofluorescence Microscopy ◽  
Fungal Endophytes ◽  
Natural Populations ◽  
Plant Invasions ◽  
Root Colonisation ◽  
Root Endophyte ◽  
Fungal Root Endophytes ◽  
Positive Effect

Abstract There is increasing evidence that microbes play a key role in some plant invasions. A diverse and widespread but little understood group of plant-associated microbes are the fungal root endophytes of the order Sebacinales. They are associated with exotic populations of invasive knotweed (Reynoutria ssp.) in Europe, but their effects on the invaders are unknown. We used the recently isolated Sebacinales root endophyte Serendipita herbamans to experimentally inoculate invasive knotweed and study root colonisation and effects on knotweed growth under different environmental conditions. We verified the inoculation success and fungal colonisation through immunofluorescence microscopy and qPCR. We found that S. herbamans strongly colonized invasive knotweed in low-nutrient and shade environments, but much less under drought or benign conditions. At low nutrients, the endophyte had a positive effect on plant growth, whereas the opposite was true under shaded conditions. Our study demonstrates that the root endophyte S. herbamans has the potential to colonize invasive knotweed fine roots and impact its growth, and it could thus also play a role in natural populations. Our results also show that effects of fungal endophytes on plants can be strongly environment-dependent, and may only be visible under stressful environmental conditions.

scholarly journals No effect of a parasite on reproduction in stickleback males: a laboratory artefact?

Parasitology ◽  
2001 ◽  
Vol 122 (4) ◽  
pp. 457-464 ◽  
Author(s):  
U. CANDOLIN ◽  
H.-R. VOIGT
Keyword(s):  
Social Interactions ◽  
Environmental Conditions ◽  
Gasterosteus Aculeatus ◽  
Cost Of Reproduction ◽  
Confounding Factors ◽  
Natural Conditions ◽  
Nuptial Coloration ◽  
Schistocephalus Solidus ◽  
The Cost ◽  
Host Parasite

Experiments are often carried out in the laboratory under artificial conditions. Although this can control for confounding factors, it may eliminate important factors that under natural conditions mediate the interaction under investigation. Here, we show that different results can be gained in the field and in the laboratory regarding host–parasite interaction. In the field, courting three-spined stickleback males, Gasterosteus aculeatus, were less often infected with plerocercoids of a cestode tapeworm, Schistocephalus solidus, than shoaling males. However, when a random sample of males was allowed to nest and court females in individual aquaria in the laboratory, both uninfected and infected males built nests and courted females. Moreover, while the few infected males that courted females in the field expressed less red nuptial coloration than uninfected courting males, there was no difference in redness between infected and uninfected males in the laboratory. We argue that the different results gained in the field and in the laboratory are due to differences in the cost of reproduction, due to differences in the resource pool of the males. The favourable conditions in the laboratory exclude factors such as predation risk, social interactions, and fluctuating environmental conditions that may use up resources in the field and mediate the effect of the parasite.

scholarly journals Long‐term variation in environmental conditions influences host–parasite fitness

2019 ◽  
Vol 9 (13) ◽  
pp. 7688-7703 ◽  
Author(s):  
Karen Musgrave ◽  
Andrew W. Bartlow ◽  
Jeanne M. Fair
Keyword(s):  
Environmental Conditions ◽  
Parasite Fitness ◽  
Term Variation ◽  
Host Parasite

scholarly journals Environmental stress determines the colonization and impact of an endophytic fungus on invasive knotweed

2021 ◽  
Author(s):  
Sigisfredo Garnica ◽  
Zhiyong Liao ◽  
Samuel Hamard ◽  
Frank Waller ◽  
Madalin Parepa ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Immunofluorescence Microscopy ◽  
Fungal Endophytes ◽  
Natural Populations ◽  
Plant Invasions ◽  
List Type ◽  
Root Colonisation ◽  
Root Endophyte ◽  
Fungal Root Endophytes ◽  
Positive Effect

AbstractThere is increasing evidence that microbes play a key role in some plant invasions. A diverse and widespread but little understood group of plant-associated microbes are the fungal root endophytes of the order Sebacinales. They are associated with exotic populations of invasive knotweed (Reynoutria ssp.) in Europe, but their effects on the invaders are unknown.We used the recently isolated Sebacinales root endophyte Serendipita herbamans to experimentally inoculate invasive knotweed and study root colonisation and effects on knotweed growth under different environmental conditions. We verified the inoculation success and fungal colonisation through immunofluorescence microscopy and qPCR.We found that S. herbamans strongly colonized invasive knotweed in low-nutrient and shade environments, but much less under drought or benign conditions. At low nutrients, the endophyte had a positive effect on plant growth, whereas the opposite was true under shaded conditions.Synthesis. Our study demonstrates that the root endophyte S. herbamans has the potential to colonize invasive knotweed fine roots and impact its growth, and it could thus also play a role in natural populations. Our results also show that effects of fungal endophytes on plants can be strongly environment-dependent, and may only be visible under stressful environmental conditions.

scholarly journals Aspects of the development of Ixodes anatis under different environmental conditions in the laboratory and in the field

2020 ◽  
Author(s):  
Natasha Bansal ◽  
William Pomroy ◽  
Allen C Heath ◽  
Isabel Castro
Keyword(s):  
Life Cycle ◽  
Relative Humidity ◽  
Environmental Conditions ◽  
Life Cycles ◽  
Ixodid Ticks ◽  
Fixed Temperature ◽  
Temperature And Humidity ◽  
The Times ◽  
Evolutionary Consequences ◽  
Host Parasite

Abstract BackgroundAs parasites spend a large amount of their life cycles on their hosts, to gain a better understanding of how host-parasite systems work, information about the life cycle of the parasite is important. Numerous laboratory and few field-based studies have explored the influence of microclimates on developmental times of different stages of various species of ixodid ticks and found that most of these species develop quicker and survive better at temperatures between 18 and 26°C and relative humidity between 75% and 94%. Ixodes anatis Chilton, 1904, or kiwi tick, is an endophilic, nidicolous species endemic to North Island brown kiwi (Apteryx mantelli, NIBK) and the Tokoeka (Apteryx australis). Little is known about the environmental conditions that are ideal for the development of the kiwi tick. Our aims in this study were to determine and compare the conditions of temperature and RH that ensured the best survival, and the shortest interstadial periods for the kiwi tick, in the laboratory and outdoors inside artificial kiwi burrows.MethodsWe collected free walking engorged ticks off wild kiwi hosts and placed them in the laboratory at various fixed temperature and humidity regimes. We also placed sets of different stages of these ticks in artificial kiwi burrows and in both cases, recorded the times taken for the ticks to moult to the next stage.ResultsWe found that temperature had a larger impact on the moults between stages than relative humidity, and larvae and nymphs both showed optimum development between 10-20°C, which is lower than many other species of Ixodid ticks. However, larvae moulted quicker and survived better when saturation deficits were <1-2 mmHg (RH>94%) while for nymphs the optimum saturation deficits were 1-10 mmHg.ConclusionsWe believe that the kiwi tick has adapted to stable, but relatively cool and humid conditions in the burrows reflecting the evolutionary consequences of its association with the kiwi.

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