Two new Ophiostoma species lacking conidial states isolated from bark beetles and bark beetle-infested Abies species in Japan

2006 ◽  
Vol 84 (2) ◽  
pp. 282-293 ◽  
Author(s):  
Nobuaki Ohtaka ◽  
Hayato Masuya ◽  
Yuichi Yamaoka ◽  
Shigeru Kaneko

Two ophiostomatoid fungi without conidiophores and conidia were isolated from bark beetles and bark beetle-infested Abies spp. The teleomorph characters were similar to species of Ophiostoma, but the absence of the conidial stage hampered their exact generic assignment. Detailed morphological observations and molecular analysis clarified their generic affiliation. Consequently, they were placed in the genus Ophiostoma , but their morphology and DNA sequences did not coincide with any other species of Ophiostoma. Here, we propose these two species as Ophiostoma aoshimae sp. nov. and Ophiostoma rectangulosporium sp. nov. The former species is characterized by perithecial necks ornamented with projections and ellipsoid to oblong ascospores, and the latter species is characterized by perithecial necks ornamented with rectangular ascospores and white colonies.

Author(s):  
Kateryna Davydenko ◽  
Denys Baturkin

K. Davydenko[1], D. Baturkin[2] Intensive mortality of Pinus sylvestris trees has recently been observed in the Sumy region in eastern Ukraine. There are two pine bark beetle species (Ips acuminatus and Ips sexdentatus), which spread resulted in considerable forest damage in Ukraine. The study of ophiostomatoid fungi vectored by bark beetles is very important to assess total harm of these insects. Therefore, the aim of our research was i) to identify ophiostomatoid fungi associated with weakened and dying Scots pine trees infested by bark beetles in the Sumy region; ii) to test the pathogenicity of these ophiostomatoid fungi to evaluate their potential threat to Scots pine. The fungi were isolated from bark beetle galleries and identified based on morphological properties and DNA sequences. In total, eight ophiostomatoid fungi (Graphium sp., Grosmannia sp.1, Ophiostoma bicolor, O. ips, O. canum, O. piceae, O. minus, Ophiostoma sp.1) were isolated from Scots pine trees infested by bark beetles. Scots pine seedlings were inoculated with eight fungi and sterile medium (control) to evaluate their pathogenicity. The inoculated seedlings were examined finally in 6 month after inoculation. Inoculation with O. minus produced significantly largest lesions and only this fungus caused mortality of pine seedlings. In total, all eight fungal species inoculated caused resin exudation and staining the bark around inoculations in Scots pine seedlings and five fungi caused different rate of seedlings decline. The size of stained sapwood was also greater following O. minus inoculations than other fungi or the control. All ophiostomatoid fungi caused significantly longer necrotic lesions and more occlusions in the sapwood than the controls. Therefore, based on the ability of various ophiostomatoid fungi to weaken and kill pine seedlings and stain sapwood, O. minus was the most dangerous species for Scots pine trees, followed by Graphium sp. and Ophiostoma sp.1. The occurrence of ophiostmatoid fungi in the sapwood of Scots pine is consistent with the concept of their primary role in the colonization of the fresh sapwood of trees in the succession of microorganisms during wood decay.    


Author(s):  
Kateryna Davydenko

Pine bark beetles are typically associated with complexes of fungi that could reveal different functional interaction. Thus, previously nonaggressive bark beetle Ips acuminatus is considering now to be among the most serious pests of pine forest in Ukraine and other European countries and vectored fungal community is very important to assess total harm of this bark beetle. The aim of this study was to reveal the vectored fungal community associated with the pine engraver beetle, I. acuminatus with special emphasis on pathogenic fungi for further evaluation of harm bark-beetle - fungi association for Ukrainian forest. In total, 288 adult beetles were collected from Scots pine trees at six different sites through Ukraine. DNA sequencing as fungal culturing from all beetles resulted in 1681 isolates and amplicons representing 42 fungal taxa. NCBI BLAST search revealed that the overall fungal community was composed of 94 species, of which 80.85% were Ascomycota, followed by Basidiomycota and unidentified fungal group, which accounted for 10.6% and 8.5 % of the total sequences, respectively. Among these, the most commonly detected fungi for pooling dataset were Sphaeropsis sapinea (23.6%), Cladosporium pini-ponderosae (19.44%), Ophiostoma ips (19.1%), Ophiostoma canum (19.1%) and Cladobotryum mycophilum (18.06%). In the pooled dataset of isolates and amplicons for each site, Shannon diversity indices ranged between 1.9 and 2.9 while Simpson diversity index varied between 0.69 and 0.89 indicating rich species diversity. In total twelve ophiostomatoid species were detected. All ophiostomatoid fungi were showing varying degrees of virulence and O. minus was the most aggressive fungus in previous studies. It is concluded that I. acuminatus vectors a species-rich fungal community including pathogens such as ophiostomatoid fungi, Sphaeropsis sapinea, different needle pathogens and wood decay fungi that seems to be very important for the assessment of threat of I. acuminatus to the pine forest in Ukraine.


2019 ◽  
Vol 42 (1) ◽  
pp. 50-74 ◽  
Author(s):  
R. Chang ◽  
T.A. Duong ◽  
S.J. Taerum ◽  
M.J. Wingfield ◽  
X. Zhou ◽  
...  

Ips typographus (Coleoptera, Scolytinae) is a spruce-infesting bark beetle that occurs throughout Europe and Asia. The beetle can cause considerable damage, especially when colonized trees are stressed and beetle populations increase. Although some studies have shown that populations of I. typographus in Europe, China and Japan are genetically distinct, these populations are biologically similar, including a strong association with ophiostomatoid fungi. To date, only two Leptographium spp. have been reported from the beetle in China, while 40 species have been reported from Europe and 13 from Japan. The aims of this study were to identify the ophiostomatoid fungal associates of I. typographus in north-eastern China, and to determine whether the fungal assemblages reflect the different geographical populations of the beetle. Field surveys in Jilin and Heilongjiang provinces yielded a total of 1046 fungal isolates from 145 beetles and 178 galleries. Isolates were grouped based on morphology and representatives of each group were identified using DNA sequences of the ribosomal LSU, ITS, β-tubulin, calmodulin and elongation factor 1-α gene regions. A total of 23 species of ophiostomatoid fungi were identified, including 12 previously described species and 11 novel species, all of which are described here. The dominant species were Ophiostoma bicolor, Leptographium taigense and Grosmannia piceiperda D, representing 40.5 %, 27.8 % and 17.8 % of the isolates, respectively. Comparisons of species from China, Europe and Japan are complicated by the fact that some of the European and all the Japanese species were identified based only on morphology. However, assuming that those identifications are correct, five species were shared between Europe, Japan and China, two species were shared between China and Japan, five between Europe and China, and two between Europe and Japan. Consequently, Ips typographus populations in these different geographic areas have different fungal assemblages, suggesting that the majority of these beetle-associations are promiscuous. The results also suggested that the symbionts of the bark beetle do not reflect the population structures of the beetle. The use of fungal symbiont assemblages to infer population structures and invasion history of its vectors should thus be interpreted with circumspection.


MycoKeys ◽  
2019 ◽  
Vol 50 ◽  
pp. 93-133 ◽  
Author(s):  
Wang HuiMin ◽  
Zheng Wang ◽  
Fu Liu ◽  
Cheng Xu Wu ◽  
Su Fang Zhang ◽  
...  

Bark beetles and their associated fungi, which cause forest decline and sometimes high mortality in large areas around the world, are of increasing concern in terms of forest health. ThreeTomicusspp. (T.brevipilosus,T.minorandT.yunnanensis) infect branches and trunks ofPinusyunnanensisandP.kesiyain Yunnan Province, in south-western China.Tomicusspp. are well known as vectors of ophiostomatoid fungi and their co-occurrence could result in serious ecological and economic impact on local forest ecosystems. Nonetheless, knowledge about their diversity, ecology, including pathogenicity and potential economic importance is still quite rudimentary. Therefore, an extensive survey of ophiostomatoid fungi associated with theseTomicusspecies infestingP.yunnanensisandP.kesiyawas carried out in Yunnan. Seven hundred and seventy-two strains of ophiostomatoid fungi were isolated from the adult beetles and their galleries. The strains were identified based on comparisons of multiple DNA sequences, including the nuclear ribosomal large subunit (LSU) region, the internal transcribed spacer regions 1 and 2, together with the intervening 5.8S gene (ITS) and the partial genes of β-tubulin (TUB2), elongation factor 1α (TEF1-α) and calmodulin (CAL). Phylogenetic analyses were performed using maximum parsimony (MP) as well as maximum likelihood (ML). Combinations of culture features, morphological characters and temperature-dependent growth rates were also employed for species identification. Eleven species belonging to five genera were identified. These included six known species,Esteyavermicola,Leptographiumyunnanense,Ophiostomabrevipilosi,O.canum,O.minusandO.tingensand four novel taxa, described asGraphilbumanningense,O.aggregatum,SporothrixpseudoabietinaandS.macroconidia. A residual strain was left unidentified asOphiostomasp. 1. The overall ophiostomatoid community was by far dominated by three species, representing 87.3% of the total isolates; in decreasing order, these wereO.canum,O.brevipilosiandO.minus. Furthermore, the ophiostomatoid community of each beetle, although harbouring a diversity of ophiostomatoid species, was differentially dominated by a single fungal species;Ophiostomacanumwas preferentially associated with and dominated the ophiostomatoid community ofT.minor, whereasO.brevipilosiandO.minuswere exclusively associated with and dominated the ophiostomatoid communities ofT.brevipilosusandT.yunnanensis, respectively. Eight additional species, representing the remaining 12.7% of the total isolates, were marginal or sporadic. These results suggested that sympatricTomicuspopulations are dominated by distinct species showing some level of specificity or even exclusivity.


Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1795
Author(s):  
Zheng Wang ◽  
Ya Liu ◽  
Caixia Liu ◽  
Zhenyu Liu ◽  
Lijun Liang ◽  
...  

Ophiostomatoid fungi are known for their associations with bark beetles, and some species are important sources of tree diseases. Ceratocystiopsis is a genus of the ophiostomatoid fungi in order Ophiostomatales. The shortage of DNA barcodes for many species in this genus has resulted in the presence of many unnamed cryptic species. In this study, Ceratocystiopsis subelongati sp. nov. associated with Ips subelongatus infesting Pinus sylvestris var. mongolica in Inner Mongolia, China, was identified and described based on phylogenetic inference of multi-gene DNA sequences and morphological characteristics. The species is characterized by a hyalorhinocladiella- to sporothrix-like asexual state and an optimal growth temperature of 30 °C. Artificial inoculation tests in the field showed that it is mildly pathogenic to five-year-old larch trees, the main host of I. subelongatus. It is also the first described Ceratocystiopsis species associated with I. subelongatus in China. This discovery should provide new avenues for studying the symbiosis between bark beetles and ophiostomatoid fungi.


Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1290
Author(s):  
Branislav Hroššo ◽  
Pavel Mezei ◽  
Mária Potterf ◽  
Andrej Majdák ◽  
Miroslav Blaženec ◽  
...  

Research Highlights: Bark beetles are important agents of disturbance regimes in temperate forests, and specifically in a connected wind-bark beetle disturbance system. Large-scale windthrows trigger population growth of the European spruce bark beetle (Ips typographus L.) from endemic to epidemic levels, thereby allowing the killing of Norway spruce trees over several consecutive years. Background and Objectives: There is a lack of evidence to differentiate how outbreaks are promoted by the effects of environmental variables versus beetle preferences of trees from endemic to outbreak. However, little is known about how individual downed-tree characteristics and local conditions such as tree orientation and solar radiation affect beetle colonization of downed trees. Materials and Methods: To answer this question, we investigated the infestation rates and determined tree death categories (uprooted, broken, and stump) in wind-damaged areas in Western Tatra Mts. in Carpathians (Slovakia) from 2014–2016, following a windthrow in May 2014. In total, we investigated 225 trees over eight transects. For every tree, we measured its morphological (tree height, crown characteristics), environmental (solar radiation, terrain conditions, trunk zenith), temporal (time since wind damage), and beetle infestation (presence, location of attack, bark desiccation) parameters. We applied Generalized Additive Mixed Models (GAMM) to unravel the main drivers of I. typographus infestations. Results: Over the first year, beetles preferred to attack broken trees and sun-exposed trunk sides over uprooted trees; the infestation on shaded sides started in the second year along with the infestation of uprooted trees with lower desiccation rates. We found that time since wind damage, stem length, and incident solar radiation increased the probability of beetle infestation, although both solar radiation and trunk zenith exhibited nonlinear variability. Our novel variable trunk zenith appeared to be an important predictor of bark beetle infestation probability. We conclude that trunk zenith as a simple measure defining the position of downed trees over the terrain can anticipate beetle infestation. Conclusions: Our findings contribute to understanding of the bark beetle’s preferences to colonize windthrown trees in the initial years after the primary wind damage. Further, our findings can help to identify trees that are most susceptible to beetle infestation and to prioritize management actions to control beetle population while maintaining biodiversity.


1980 ◽  
Vol 112 (7) ◽  
pp. 725-730 ◽  
Author(s):  
D. J. Goheen ◽  
F. W. Cobb

AbstractThe relationship between bark beetle infestation of ponderosa pine and severity of infection by Ceratocystis wageneri was investigated by closely monitoring 256 trees (136 apparently healthy, 60 moderately diseased, and 60 severely diseased at initiation of study) for beetle infestation from summer 1972 to fall 1975. Disease ratings were updated by periodic examination, and some trees changed disease category during the study. Ninety trees were infested by Dendroctonus brevicomis, D. ponderosae, or both, five by buprestids alone, and one tree died from effects of the pathogen alone. Sixty-two of the beetle-infested trees were severely diseased at time of infestation, 25 were moderately diseased, and only three were apparently healthy. Thus, the results showed that bark beetles were much more likely to infest infected than healthy trees. Among diseased trees, those with advanced infections were most likely to be infested. There was evidence that buprestids (especially Melanophila spp.) and possibly Ips spp. attacked diseased trees prior to Dendroctonus spp. infestation.


1990 ◽  
Vol 122 (3) ◽  
pp. 423-427 ◽  
Author(s):  
Thomas W. Phillips

AbstractResults of a field experiment indicate that adults of the pine weevil Hylobius pales (Herbst) respond to pheromones of bark beetles. Each sex of H. pales was more attracted to traps baited with the combination of a pine bolt infested with male Ips calligraphus Germar plus the synthetic Dendroctonus Erichson pheromones frontalin and exo-brevicomin, than to traps baited with pine bolts alone. The combined numbers of male and female H. pales caught in traps baited only with Ips calligraphus-infested bolts were significantly greater than numbers caught in traps baited with uninfested control bolts. The attraction of H. pales to bark beetle pheromones may represent a kairomonal response in which weevils exploit semiochemicals from other species that signify a suitable host resource.


2021 ◽  
Author(s):  
Erica Jaakkola ◽  
Anna Maria Jönsson ◽  
Per-Ola Olsson ◽  
Maj-Lena Linderson ◽  
Thomas Holst

<p>Tree killing by spruce bark beetles (<em>Ips typographus</em>) is one of the main disturbances to Norway spruce (<em>Picea abies</em>) forests in Europe and the risk of outbreaks is amplified by climate change with effects such as increased risk of storm felling, tree drought stress and an additional generation of spruce bark beetles per year<sup>[1]</sup>. The warm and dry summer of 2018 triggered large outbreaks in Sweden, the increased outbreaks are still ongoing and affected about 8 million m<sup>3</sup> forest in 2020<sup>[2]</sup>. This is the so far highest record of trees killed by the spruce bark beetle in a single year in Sweden<sup>[2]</sup>. In 1990-2010, the spruce bark beetle killed on average 150 000 m<sup>3</sup> forest per year in southern Sweden<sup>[3]</sup>. Bark beetles normally seek and attack Norway spruces with lowered defense, i.e. trees that are wind-felled or experience prolonged drought stress<sup>[4]</sup>. However, as the number of bark beetle outbreaks increase, the risk of attacks on healthy trees also increase<sup>[5]</sup>. This causes a higher threat to forest industry, and lowers the possibilities to mitigate climate change in terms of potential decreases in carbon uptake if the forests die<sup>[4,5]</sup>. Norway spruce trees normally defend themselves by drenching the beetles in resin<sup>[6]</sup>. The resin in turn contains different biogenic volatile organic compounds (BVOCs), which can vary if the spruce is attacked by bark beetles or not<sup> [4,6]</sup>. The most abundant group of terpenoids (isoprene, monoterpenes and sesquiterpenes), is most commonly emitted from conifers, such as Norway spruce<sup>[7,8]</sup>. The aim of this study was to enable a better understanding of the direct defense mechanisms of spruce trees by quantifying BVOC emissions and its composition from individual trees under attack</p><p>To analyze the bark beetles’ impact on Norway spruce trees a method was developed using tree trunk chambers and adsorbent tubes. This enables direct measurements of the production of BVOCs from individual trees. Three different sites in Sweden, with different environmental conditions were used for the study and samples were collected throughout the growing season of 2019. After sampling, the tubes were analyzed in a lab using automated thermal desorption coupled to a gas chromatograph and a mass spectrometer to identify BVOC species and their quantity.</p><p>The preliminary results show a strong increase in BVOC emissions from a healthy tree that became infested during the data collection. The finalized results expect to enable better understanding of how spruce trees are affected by insect stress from bark beetles, and if bark beetle infestation will potentially result in increased carbon emission in the form of BVOCs.</p><p><strong>References</strong></p><p>[1] Jönsson et al. (2012). Agricultural and Forest Meteorology 166: 188–200<br>[2] Skogsstyrelsen, (2020). https://via.tt.se/pressmeddelande/miljontals-granar-dodades-av-granbarkborren-2020?publisherId=415163&releaseId=3288473<br>[3] Marini et al. (2017). Ecography, 40(12), 1426–1435.<br>[4] Raffa (1991). Photochemical induction by herbivores. pp. 245-276<strong><br></strong>[5] Seidl, et al. (2014). Nature Climate Change, 4(9), 806-810. <br>[6] Ghimire, et al. (2016). Atmospheric Environment, 126, 145-152.<br>[7] Niinemets, U. and Monson, R. (2013). ISBN 978-94-007-6606-8<br>[8] Kesselmeier, J. and Staudt, M. (1999). Journal of Atmospheric Chemistry, 33(1), pp.23-88</p>


2021 ◽  
Author(s):  
Runlei Chang ◽  
Xiuyu Zhang ◽  
Hongli Si ◽  
Guoyan Zhao ◽  
Xiaowen Yuan ◽  
...  

Abstract Cryphalus piceae parasitizes various economically important conifers. Similar to other bark beetles, C. picea vectors an assortment of fungi and nematodes. Previously, several ophiostomatoid fungi were isolated from C. piceae in Poland and Japan. In the present study, we explored the diversity of ophiostomatoid fungi associated with C. piceae infesting pines in the Shandong Province of China. We isolated ophiostomatoid fungi from both galleries and beetles collected from our study sites. These fungal isolates were identified using both molecular and morphological data. Through this study, we recovered 176 isolates of ophiostomatoid fungi representing at least seven species. Ophiostoma ips was the most frequently isolated species. Analyses of molecular and morphological data indicated four of the ophiostomatoid fungal species recovered in this study were previously undescribed. Hereby, we described these species as Ceratocystiopsis yantaiensis sp. nov., C. weihaiensis sp. nov., Graphilbum translucens sp. nov. and Sporothrix villosa sp. nov. A majority of the ophiostomatoid fungi recovered in this study were novel species. This suggests that the forests in China harbour an assortment of undescribed ophiostomatoid fungi yet to be discovered.


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