Reevaluation of the Status of the Bluestain Fungus and Bark Beetle Associate Ophiostoma minus

Gorton, Caroline; Webber, Joan

doi:10.2307/3761474

Cited by 20 publications

(15 citation statements)

References 23 publications

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“…Tarsonemus may have additional importance in the evolutionary ecology of O. minus because mites are the main way in which ascospores, which are the product of sexual reproduction, are transported (Moser 1985, Lombardero et al 2000). Recent work has identified the existence of, and variability within, multiple mating types of O. minus (Uzonovic 1997, Gorton and Webber 2000). Mites may be especially important in bringing together compatible mating types of O. minus and thus perpetuating outcrossing and variability within this fungus.…”

Section: Discussionmentioning

confidence: 99%

Strong indirect interactions of Tarsonemus mites (Acarina: Tarsonemidae) and Dendroctonus frontalis (Coleoptera: Scolytidae)

Lombardero¹,

Ayres²,

Hofstetter³

et al. 2003

Oikos

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Strong indirect interactions of Tarsonemus mites (Acarina: Tarsonemidae) and Dendroctonus frontalis (Coleoptera: Scolytidae). -Oikos 102: 243-252. Phoretic mites of bark beetles are classic examples of commensal ectosymbionts.However, many such mites appear to have mutualisms with fungi that could themselves interact with beetles. We tested for indirect effects of phoretic mites on Dendroctonus frontalis, which attacks and kills pine trees in North America. Tarsonemus mites are known to carry ascospores of Ophiostoma minus, which tends to outcompete the mutualistic fungi carried by D. frontalis. Experimental additions and removals of mites from beetles demonstrated that Tarsonemus propagate O. minus in beetle oviposition galleries. Furthermore, the abundance of Tarsonemus and O. minus tended to covary in nature. These results verified a strong mutualism between Tarsonemus and O. minus. Results also indicated that O. minus is an antagonist of D. frontalis: beetle larvae seldom survived in the presence of O. minus (compared to 83% survival elsewhere). Apparently, this is an indirect result of O. minus outcompeting the two species of mycangial fungi that are critical to beetle nutrition. Thus, Tarsonemus mites close a loop of species interactions that includes a commensalism (mites and beetles), a mutualism (mites and O. minus), asymmetric competition (O.minus and mycangial fungi), and another mutualism (mycangial fungi and beetles). This interaction system produces negative feedback that could contribute to the endogenous population dynamics of D. frontalis. Reproductive rate of Tarsonemus was more temperature-sensitive than beetle generation time (which constrains the time for mite reproduction within a tree). This differential temperature sensitivity produces a narrow range of temperatures (centred at 27°C) in which mite reproduction per D. frontalis generation can attain its maximum of 100 mites/beetle. Consequently, seasonal oscillations in temperature are predicted to produce oscillations in the D. frontalis community, and climatic differences between regions could influence the community to dampen or exacerbate the cyclical outbreak dynamics of D. frontalis.

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Section: Discussionmentioning

confidence: 99%

Strong indirect interactions of Tarsonemus mites (Acarina: Tarsonemidae) and Dendroctonus frontalis (Coleoptera: Scolytidae)

Lombardero¹,

Ayres²,

Hofstetter³

et al. 2003

Oikos

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“…Recent phylogenetic analyses have shown that O. minus isolates collected in Europe and China are distinct from isolates collected from North America that include also the type of O. minus (Hedgcock 1906, Gorton and Webber 2000, Gorton et al 2004, Lu et al 2009). This distinction was observed also in our study (study III).…”

Section: Sibling Species Within the Ophiostomatoid Fungimentioning

confidence: 99%

Bark beetle-associated fungi in Fennoscandia with special emphasis on species of Ophiostoma and Grosmannia

Linnakoski¹

2011

Diss. For.

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Global trade in untreated timber and wood products raises the risk of accidentally introducing forest pests and pathogens into new environments. Bark beetles (Coleoptera: Scolytinae) include several species that are regarded as forest pests. These insects are known to live in close association with fungi, especially species of ophiostomatoid fungi (Ascomycota). Several of these fungi are agents of blue stain in timber, and some are serious plant pathogens. However, only little is known regarding the fungal associates of bark beetles, or the interactions between the fungus, the bark beetle and the host tree in the boreal forests of Fennoscandia.The aim of this study was to increase the knowledge regarding bark beetle-associated fungi in Fennoscandia, with special emphasis on the genera Ophiostoma Syd. & P. Syd. and Grosmannia Goid. Fungi associated with 13 different bark beetle species, infesting Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestris L.) and birches (Betula L. spp.) in the eastern parts of Finland and neighboring Russia, as well as southern Norway, were isolated and identified. The fungal identifications were based on morphological characteristics and DNA sequence comparisons.The survey revealed the occurrence of at least 29 species of Ophiostoma and Grosmannia. All the bark beetle species considered in this study were frequently associated with a complex of ophiostomatoid fungi. Several species were recorded for the first time in the countries in the study. A surprisingly high number of previously undescribed fungal species were discovered. During the survey, eight of these species were described as new taxa. In addition, the study revealed new insect-fungus relationships. The number of taxa encountered, covering a relatively small geographical area, indicates that there are many more ophiostomatoid fungi occurring in the boreal forests of Fennoscandia than has previously been recognized. The study emphasizes the importance of developing a clear understanding of the possible threats of moving timber and wood products without knowledge of the micro-organisms that might also be moved.Keywords: blue stain, insect-fungus interactions, molecular systematics, ophiostomatoid fungi, Ophiostomatales, symbioses 4 ACKNOWLEDGEMENTS "It's the journey that's important, not the getting there" (John McLeod). The writing of this dissertation has been a fascinating journey full of unforgettable experiences, from South African sunrises to a rail ride on the Trans Siberian Railway. It has also been a time of personal growth. The writing of a dissertation is a long journey, and obviously not possible without the support of numerous people. I've been truly privileged to start my journey in the world of science with many inspiring people. It's been a great pleasure to follow their enthusiasm and the deep commitment to the work they love. Thank you for passing on the passion for science! I would like to express my sincere thanks to all of you who have contributed and supported this project in v...

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“…For example, the Dutch elm disease pathogens and O. quercus are heterothallic (Brasier and Kirk 1993;Harrington et al 2001;Solla et al 2008) where sexual reproduction requires the interaction of two individuals of opposite mating type (Coppin et al 1997). In contrast, individuals of homothallic species (e.g., O. arduennense and O. minus) are typically self-fertile and capable of completing the sexual cycle in the absence of a second individual (Carlier et al 2006;Gorton and Webber 2000;Grobbelaar et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Both mating types in the heterothallic fungus Ophiostoma quercus contain MAT1-1 and MAT1-2 genes

et al. 2012

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In heterothallic Ascomycota, two opposite but distinct mating types control all sexual processes. Using mating crosses on agar plates, the heterothallic nature of the wood-inhabiting fungus Ophiostoma quercus was confirmed and mating types were assigned to 10 isolates. Primers were subsequently designed to target both the mating type 1 (MAT1-1) and 2 (MAT1-2) idiomorphs in these isolates. The results showed that all isolates contained sequence fragments representing both idiomorphs. This was unexpected, as each isolate from a heterothallic species would typically contain only one of the two possible MAT idiomorphs. An atypical mating system such as the one described in this study has not previously been encountered in any other Ascomycota mating locus described to date.

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Reevaluation of the Status of the Bluestain Fungus and Bark Beetle Associate Ophiostoma minus

Cited by 20 publications

References 23 publications

Strong indirect interactions of Tarsonemus mites (Acarina: Tarsonemidae) and Dendroctonus frontalis (Coleoptera: Scolytidae)

Strong indirect interactions of Tarsonemus mites (Acarina: Tarsonemidae) and Dendroctonus frontalis (Coleoptera: Scolytidae)

Bark beetle-associated fungi in Fennoscandia with special emphasis on species of Ophiostoma and Grosmannia

Both mating types in the heterothallic fungus Ophiostoma quercus contain MAT1-1 and MAT1-2 genes

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