Bacterial associations of coniferous mycorrhizae

Summary A study was made of the bacterial flora associated with mycorrhizae and non-mycorrhizal roots ofPicea engelmanni, P. pungens, Pinus aristata, P. flexilis, andPseudotsuga menziesii seedlings up to 3 dm in height.A total of 369 bacterial isolations were made, of which 116 cultures were lost, mainly as a result of dying out. Fifty-one species were recognized from the surviving cultures. Of these, 22 were associated with only mycorrhizae and seven with only non-mycorrhizal roots. Most species grew best on media containing glucose.Picea engelmanni andPinus aristata were hosts to the greatest variety of bacterial species.Research conducted in partial fulfillment of the requirements for the M. A. degree Western State College, Gunnison, Colorado, 1963.     

Tree growth response to drought and temperature in a mountain landscape in northern Arizona, USA

Aim To understand how tree growth response to regional drought and temperature varies between tree species, elevations and forest types in a mountain landscape. Location Twenty‐one sites on an elevation gradient of 1500 m on the San Francisco Peaks, northern Arizona, USA. Methods Tree‐ring data for the years 1950–2000 for eight tree species (Abies lasiocarpa var. arizonica (Merriam) Lemm., Picea engelmannii Parry ex Engelm., Pinus aristata Engelm., Pinus edulis Engelm., Pinus flexilis James, Pinus ponderosa Dougl. ex Laws., Pseudotsuga menziesii var. glauca (Beissn.) Franco and Quercus gambelii Nutt.) were used to compare sensitivity of radial growth to regional drought and temperature among co‐occurring species at the same site, and between sites that differed in elevation and species composition. Results For Picea engelmannii, Pinus flexilis, Pinus ponderosa and Pseudotsuga menziesii, trees in drier, low‐elevation stands generally had greater sensitivity of radial growth to regional drought than trees of the same species in wetter, high‐elevation stands. Species low in their elevational range had greater drought sensitivity than co‐occurring species high in their elevational range at the pinyon‐juniper/ponderosa pine forest ecotone, ponderosa pine/mixed conifer forest ecotone and high‐elevation invaded meadows, but not at the mixed conifer/subalpine forest ecotone. Sensitivity of radial growth to regional drought was greater at drier, low‐elevation compared with wetter, high‐elevation forests. Yearly growth was positively correlated with measures of regional water availability at all sites, except high‐elevation invaded meadows where growth was weakly correlated with all climatic factors. Yearly growth in high‐elevation forests up to 3300 m a.s.l. was more strongly correlated with water availability than temperature. Main conclusions Severe regional drought reduced growth of all dominant tree species over a gradient of precipitation and temperature represented by a 1500‐m change in elevation, but response to drought varied between species and stands. Growth was reduced the most in drier, low‐elevation forests and in species growing low in their elevational range in ecotones, and the least for trees that had recently invaded high‐elevation meadows. Constraints on tree growth from drought and high temperature are important for high‐elevation subalpine forests located near the southern‐most range of the dominant species.     

Vesicular mycorrhizal colonization of seedlings of Pinaceae and Betulaceae after spore inoculation with Glomus intraradices

 Although Pinaceae and Betulaceae have been reported to contain Glomus–type root endophytes, its ecological importance and the conditions influencing this symbiosis are poorly understood. Seedlings of Abies lasiocarpa, Alnus rubra, Pinus contorta, Pinus ponderosa, Pseudotsuga menziesii, and Tsuga heterophylla were inoculated with Glomus intraradices to determine the vesicular-arbuscular mycorrhizae (VAM) development and responsiveness of these hosts. The role of companion VAM host plants on mycorrhizal colonization and nutrient uptake by Pseudotsuga menziesii was also examined by growing seedlings of Pseudotsuga menziesii in dual culture with VAM hosts Thuja plicata or Calamagrostis rubescens. After 8 weeks, no seedlings were colonized. At 16 weeks, 8 of 17 Thuja plicata seedlings grown with Pseudotsuga menziesii and all 18 inoculated Thuja plicata seedlings grown alone were colonized with vesicles and hyphae. Two of 17 inoculated Pseudotsuga menziesii seedlings grown in dual culture with Thuja plicata were colonized with abundant vesicles and hyphae. No ectomycorrhizal seedlings grown in monoculture were colonized. At 9 months, all 10 Calamagrostis rubescens and all 10 inoculated Pseudotsuga menziesii seedlings grown in dual culture were colonized by vesicles and hyphae. Two of 10 inoculated Pseudotsuga menziesiiand 1 of 10 inoculated Pinus ponderosa seedlings grown in monoculture were similarly colonized. The mean phosphorus content in the needles of colonized Pseudotsuga menziesii seedlings grown with Calamagrostis rubescens was about twice as high as in noncolonized Pseudotsuga menziesiiseedlings grown with Calamagrostis rubescens. Tissue nitrogen did not differ between these treatments. The results show that Glomus intraradices colonization of Pinaceae is most successful when a VAM host is present, although some vesicular colonization of Pinaceae occurred in the absence of a VAM host. Accepted: 24 September 1997     

Inter- and intraspecific polymorphism at chloroplast SSR loci and the inheritance of plastids in Pinus radiata D. Don

DNA sequence analysis of chloroplast genomes has revealed many short nucleotide repeats analogous to nuclear microsatellites, or simple sequence repeats (SSRs). We designed PCR primers flanking five of these regions identified in the chloroplast sequence from Pinus thunbergii and tested them for amplification in Pinus radiata, P. elliotii, P. taeda, P. strobus, Pseudotsuga menziesii, Cupressus macrocarpa, four New Zealand native conifer species (Podocarpus totara, Podocarpus hallii, Podocarpus nivalis, Agathis australis), and four angiosperms (Vitex lucens, Nestegis cunninghamii, Actinidia chinensis, and Arabidopsis thaliana). A PCR product in the expected size range was amplified from all species and interspecific polymorphism was detected at all five loci. Intraspecific polymorphism was detected in P. radiata with four of the five primer pairs. One of these polymorphic chloroplast SSR (cpSSR) was then used to determine the inheritance of chloroplasts in 206 progeny from four control-pollinated, full-sibling P. radiata families. Approximately 99% of the progeny had the cpSSR variant of the pollen parent indicating that in Pinus radiata, like most other conifers, chloroplasts are typically inherited from the paternal parent. These results suggest that polymorphic chloroplast SSRs will be a valuable tool for studying chloroplast diversity, cyto-nuclear disequilibrium, and plastid inheritance in a range of species, and for the analysis of gene flow via pollen and paternity in species with paternal transmission of chloroplasts.     

A chalcone synthase/stilbene synthase DNA probe for conifers

A probe for chalcone synthase (CHS) was generated by PCR using chalcone synthase conserved sequences. The cloned PCR product has high similarity to both chalcone synthase and stilbene synthase sequences. The probe was used to examine the organization of chalcone synthase and stilbene synthase genes in Abies procera, Pinus lambertiana, P. monticola, Picea glauca, P. sitchensis, Pseudostuga menziesii, Taxus brevifolia, and Thuja plicata. A large number of hybridizing bands were found in all species except T. plicata which did not cross hybridize. The hybridization patterns are highly polymorphic between the species and are also polymorphic within several of them.     

Influence of aluminum on in vitro formation of Pinus caribaea mycorrhizae

The ability of Pinus caribaea var. hondurensis to form mycorrhizae was determined in vitro with seven species of ectomycorrhizal fungi in the presence of six levels of Al (added as AlCl₃) in a nutrient solution. The time required for mycorrhizal formation, the number of mycorrhizal root tips and the percent mycorrhizae were measured after 15, 30, 60, 90 and 120 days. Cenococcum graniforme was susceptible to Al toxicity at all Al concentrations. Pisolithus tinctorius and Suillus sp. were depressed at lower but stimulated at higher Al concentrations. The inverse was shown for Rhizopogon reaii and Hebeloma cylindrosporum. Tolerance to Al was verified for R. nigrescens and H. crustuliniforme. Pisolithus tinctorius had the largest mycorrhizal capacity, defined as the sum of the values for time, percent and number of mycorrhizae. Ectomycorrhizal fungi appeared to ameliorate Al damage to plant roots even in treatments where no mycorrhizae formed. Inoculation of pine seedlings with Al-tolerant mycorrhizal fungi is likely to improve reforestation efforts in highly-weathered tropical soils.     

Breeding performance and longevity of Tomicus destruens on Mediterranean and continental pine species

The pine shoot beetle Tomicus destruens (Wollaston) (Coleoptera: Curculionidae: Scolytinae) is one of the main pests of Mediterranean forests, where it is oligophagous on Mediterranean pines. However, possible global warming may make the insect move to higher latitudes and altitudes, allowing it to attack new pine species. In this respect, the aim of the present article was to assess both the acceptance and performance of T. destruens offered host and non‐host pine species. A no‐choice breeding experiment was set up under laboratory conditions, using logs of three Mediterranean (Pinus pinea L., Pinus pinaster Miller, and Pinus halepensis Aiton) and two continental (Pinus nigra Arnold and Pinus sylvestris L.) pine species. Log debarking at the end of adult emergence assessed parent fecundity, egg, and larval mortality. The quality of callow adults emerging from each tested pine was evaluated on the basis of their longevity on a semiartificial diet. Tomicus destruens colonised all tested pine species, but did not reproduce in Scots pine, taking about 79 days to complete development with no differences among pines tested. The best breeding performance, evaluated as female fecundity and adult production, was observed in P. halepensis, and the lowest in P. pinaster. On average, adults emerging from P. pinea survived longer (83 days) than from other pines, and adult longevity was the lowest in males emerging from P. nigra. Austrian pine, which under natural conditions is usually not a host of T. destruens, allowed insect development and adult production similar to P. pinea and P. pinaster.     

Mapped DNA probes from loblolly pine can be used for restriction fragment length polymorphism mapping in other conifers

A high-density genetic map based on restriction fragment length polymorphisms (RFLPs) is being constructed for loblolly pine (Pinus taeda L.). Consequently, a large number of DNA probes from loblolly pine are potentially available for use in other species. We have used some of these DNA probes to detect RFLPs in 12 conifers and an angiosperm. Thirty complementary DNA and two genomic DNA probes from loblolly pine were hybridized to Southern blots containing DNA from five species of Pinus (P. elliottii, P. lambertiana, P. radiata, P. sylvestris, and P. taeda), one species from each of four other genera of Pinaceae (Abies concolor, Larix laricina, Picea abies, and Pseudotsuga menziesii), one species from each of three other families of Coniferales [Sequoia sempervirens (Taxodiaceae), Torreya californica (Taxaceae) and Calocedrus decurrens (Cupressaceae)], and to one angiosperm species (Populus nigra). Results showed that mapped DNA probes from lobolly pine will cross-hybridize to genomic DNA of other species of Pinus and some other genera of the Pinaceae. Only a small proportion of the probes hybridized to genomic DNA from three other families of the Coniferales and the one angiosperm examined. This study demonstrates that mapped DNA probes from loblolly pine can be used to construct RFLP maps for related species, thus enabling the opportunity for comparative genome mapping in conifers.     

Potential impact of the leaf‐cutting ant Acromyrmex lobicornis on conifer plantations in northern Patagonia,Argentina

• 1 The economic losses associated with crop damage by invasive pests can be minimized by recognizing their potential impact before they spread into new areas or crops.
• 2 We experimentally evaluated the preferences of the leaf‐cutting ant Acromyrmex lobicornis (Hymenoptera: Formicidae) for the most common conifer species commercially planted in northern Patagonia, Argentina. The areas of potential forest interest in this region and the geographical range of this ant overlap. We performed field preference tests and monitored the level of ant herbivory on planted conifer seedlings next to nests.
• 3 Acromyrmex lobicornis preferred some conifer species and avoided foraging on others. Pseudotsuga menziesii and Austrocedrus chilensis were the less preferred species, Pinus ponderosa and Pinus contorta were the most preferred by A. lobicornis.
• 4 The item mostly selected by ants was young needles from P. contorta. This species was also the pine mostly defoliated. Seedlings without ant‐exclusion showed a mean±SE of 60±5% defoliation during the sampling period. Pinus ponderosa was less defoliated; control seedlings showed a mean±SE of 8.5±1% of leaf damage in the sampling period.
• 5 The present study shows how the use of simple field tests of leaf‐cutting ant preferences could allow an improved selection of appropriate conifer species for future plantations in areas where leaf‐cutting ants are present.

     

Phylogenetic analysis of the hard pines (Pinus subgenus Pinus,Pinaceae) from chloroplast DNA restriction site analysis

Phylogenetic analysis of plastid DNA restriction site and rearrangement mutations suggests a number of major revisions to taxonomy and phylogenetic concepts in the hard pines. Total genomic DNA from 18 species that sampled all nine subsections was digested with 19 restriction enzymes, blotted, and probed with 70% of the Douglas-fir (Pseudotsuga menziesii) chloroplast genome, or, with clones encompassing the entire chloroplast genome of Pinus contorta. A total of 204 site mutations and five rearrangement mutations were generated, of which 126 were phylogenetically informative. Wagner parsimony analyses revealed 11 clades that were strongly supported by bootstrap and decay index analyses. All North American species except P. resinosa formed a distinct monophyletic group that was strongly separated from the Eurasian species. Within the Eurasian clade subsect. Sylvestres was polyphyletic; its Mediterranean species were closely allied with members of sect. Pinea. Sect. Pinea appeared polyphyletic as well; both species of its subsect. Leiophyllae showed a close affinity to Mesoamerican pines of subsect. Oocarpae in sect. Pinus. Within the North American pines subsects. Ponderosae and Oocarpae were polyphyletic. Despite its shallow fossil record, subsect. Contortae emerged as a sister group to all of the North American pines apart from P. resinosa, which was allied with Eurasian species of subsect. Sylvestres. The remaining North American subsections formed two groups: a poorly resolved clade with subsects. Ponderosae and Sabinianae, and sequentially nested clades represented by: P. radiata; P. taeda; representatives of subsects. Oocarpae and Ponderosae from Mesoamerica, and subsect. Leiophyllae. We present estimates of divergence times for each of these major clades based on molecular clocks calibrated using two hard pine fossil observations.     

Inoculation of containerized Pseudotsuga menziesii and Pinus pinaster seedlings with spores of five species of ectomycorrhizal fungi

 Container-grown Pseudotsuga menziesii and Pinus pinaster seedlings were inoculated with water suspensions of spores of five ectomycorrhizal fungi commonly found in northeastern Spain. Pseudotsuga menziesii seedlings were inoculated with basidiospores of Melanogaster ambiguus, or Rhizopogon subareolatus, or with ascospores of Tuber maculatum. Pinus pinaster seedlings were inoculated with basidiospores of Melanogaster ambiguus, Rhizopogon roseolus or Scleroderma citrinum. The spore concentrations were 10²–10⁷ spores per seedling for Melanogaster ambiguus (in Pseu dotsuga menziesii) and Rhizopogon subareolatus, 10³–10⁷ for Melanogaster ambiguus (in Pinus pinaster), Rhizopogon roseolus, and Scleroderma citrinum, and 10²–10⁴ for Tuber maculatum. Melanogaster ambiguus colonized more short roots in a larger proportion of plants at 10⁷ spores per seedling than at any other rate. The highest colonization by Rhizopogon subareolatus was obtained at 10⁴ spores per seedling and higher, and all inoculated plants became infected at 10⁶ spores per seedling and higher. Tuber maculatum colonized a high percentage of short roots at all rates tested; the proportion of infected plants was over 80% at 10³–10⁴ spores per plant, decreasing to 50% at 10² spores per plant. Rhizopogon roseolus colonized the highest number of short roots on nearly all the inoculated plants when applied at 10⁵ spores per seedling and higher. Scleroderma citrinum colonized a high percentage of short roots on all inoculated plants when applied at 10⁵ spores per seedling and higher. The abundance of sporocarps of Melanogaster ambiguus, Rhizopogon subareolatus, R hizopogon roseolus and Scleroderma citrinum and their colonization ability at relatively low rates allows these spores to be used as ectomycorrhizal inocula on a large scale. Accepted: 27 February 1996     

Primers designed to amplify a mitochondrial nad1 intron in ponderosa pine, Pinus ponderosa, limber pine, P. flexilis, and Scots pine, P. sylvestris

The b/c intron of the mitochondrial nad1 gene, was sequenced to characterize the indel region of ponderosa pine, Pinus ponderosa. The sequence in ponderosa pine was aligned with the sequence in Scots pine, Pinus sylvestris, to design seven primers that are useful for sequencing and for revealing size variation in amplified fragments in ponderosa pine, Scots pine, and limber pine, Pinus flexilis. These primers reveal variability in all three species, and the pattern of variability within ponderosa pine is described by a preliminary survey. The indel region of ponderosa pine contains three distinct elements with lengths of 31, 32, and 34 bp. Received: 1 March 2000 / Accepted: 14 April 2000<@head-com-p1a.lf>Communicated by P.M.A. Tigerstedt     

Competition between ectomycorrhizal fungi colonizing Pinus densiflora

 Interactive competition of Pisolithus tinctorius (Pers.) Coker et Couch with an unidentified species Tanashi 01 and Suillus luteus (L.: Fr.) S. F. Gray was investigated using a rhizobox. Pinus densiflora Sieb. et Zucc. was used as the host plant and mycelia were distinguished by hyphal color. The speed of mycelial spread differed between the fungi;P. tinctorius and Tanashi 01 grew faster than S. luteus. A P. tinctorius mycorrhizal seedling and a Tanashi 01 mycorrhizal seedling were transplanted on opposite sides of the rhizobox. The mycelia and mycorrhizae of P. tinctorius were overgrown by Tanashi 01 hyphae and development of P. tinctorius was gradually inhibited. The areas occupied by mycelia and mycorrhiza of P. tinctorius decreased by 52% and 37%, respectively, 154 days after transplantation relative to that at 91 days. In the overlap area of P. tinctorius and Tanashi 01, the latter fungus infected new root tips emerging from P. tinctorius mycorrhiza, which lacked a mantle of P. tinctorius hyphae, and formed a composite mycorrhizal structure. P. tinctorius mycorrhizae were progressively replaced by Tanashi 01 mycorrhizae. Mycelial spread of P. tinctorius and S. luteus were naturally inhibited but there was no interaction in mycorrhizal formation. Accepted: 18 June 1999     

Genetic relationships among Mexican white pines (Pinus, Pinaceae) based on RAPD markers

Genetic relationships among Mexican white pines have not been completely resolved by DNA sequencing analyses. The use of random amplified polymorphic DNA (RAPD) markers for the study of interspecific relationships has been questioned because of the possible lack of homology of co-migrating bands between species. However, several RAPD based studies on pines have provided sufficient information to discriminate between closely related taxa. Genetic relationships among four species of Mexican white pines (Pinus ayacahuite, Pinus strobiformis, Pinus lambertiana and Pinus chiapensis) were estimated based on RAPD markers. Sixty-nine primers generated 247 bands in pooled DNA samples from ten populations. In addition, four selected primers generated 27 bands in 176 individual DNA samples. Unweighted Pair Group Method with Arithmetic Average (UPGMA) dendrograms based on Jaccard similarity indices were constructed. The results suggest that the closest pine species analyzed were P. ayacahuite and P. strobiformis, followed by P. lambertiana. The most genetically distant species was P. chiapensis. Cluster analyses did not support P. strobiformis as a distinct species from P. ayacahuite.     

Occurrence and dominance of six Pacific Northwest conifer species

Questions: Can probability of occurrence and dominance be accurately estimated for six important conifer species with varying range sizes? Does range size impact the accuracy of species probability of occurrence models? Is species predicted probability of occurrence significantly related to observed dominance? Location: Pacific Northwest region, North America (60°–40°N, 140°–110°W). Methods: This study develops near range‐wide predictive distribution maps for six important conifer species (Pseudotsuga menziesii, Tsuga heterophylla, Pinus contorta, Thuja plicata, Larix occidentalis, and Picea glauca) using forest inventory data collected across the United States and Canada. Species model accuracies are compared with range size using a rank scoring system. A suite of climate and topographic predictor variables are used to investigate environmental constraints that limit species range and quantify relationships between species predicted probability of occurrence and dominance at both plot and landscape scales. Results: Evaluation statistics revealed significant and accurate probability of occurrence models were developed for all six species. Based on ranked evaluation statistics, Tsuga heterophylla had highest overall model accuracy (statistic rank score=5) and Pinus contorta the lowest (statistic rank score=17). Across species, ranked evaluation statistics also revealed a pattern of decreasing model accuracy with increasing range size. At plot level, correlations between dominance and probability of occurrence were weakly positive for all species with only half of the species having statistically significant correlations. Pseudotsuga menziesii had the highest correlation (r=0.36, P<0.001) and Thuja plicata lowest (r=0.038, P=0.799). At the 50‐km scale, correlations between dominance and probability of occurrence improved for all species except Pinus contorta. Pseudotsuga menziesii displayed the highest correlation (r=0.68, P<0.001) and Thuja plicata the lowest (r=0.07, P>0.709). Conclusions: Species probability of occurrence model accuracy decreased with increasing range size. The strength and significance of correlations between probability of occurrence and dominance varied considerably by species and across spatial scales. Apart from Pseudotsuga menziesii and L. occidentalis, the results suggest that probability of occurrence is not a consistently reliable surrogate for species dominance in Pacific Northwest forests. We demonstrate how the degree of correlation between species occurrence and dominance can be used as an indicator of how well predictions of occurrence characterize the optimal niche of a species.     

Abortive embryogenesis in hybrid swarm populations of <Emphasis Type="Italic">Pinus sylvestris</Emphasis> L. and <Emphasis Type="Italic">Pinus muga</Emphasis> Turra

Comparative study on fertilization process in Pinus sylvestris, Pinus mugo and in their putative hybrid swarm individuals was done involving pre-zygotic and post-zygotic stages. The amount of surviving ovules from open pollination reflecting the mode of interaction between pollen grains and nucellar tissue of an ovule averaged at 8.1 of sound ovules per conelet in Pinus sylvestris, 7.3 ovules in the hybrid swarm population and at 4.9 ovules in Pinus mugo. A strong correlation was observed between the number of surviving ovules and the proportion of germinating seeds in the compared species and hybrids. Normal course of embryogenesis in Pinus sylvestris and Pinus mugo contrasted with increased frequency of disturbances observed in the hybrid swarm individuals. The differential survival rates of the ovules and deviations from typical pattern of embryogenesis are discussed from the standpoint of cross-ability relationship between Pinus sylvestris and Pinus mugo.     

六种阔叶树种叶片水浸提液对云南松种子萌发生长的化感作用

为了筛选营建云南松抗虫混交林的树种,该研究观察了云南切梢小蠹非寄主植物川滇桤木、缅桂、滇朴、樟树、麻栎和山茶六种阔叶树种叶片不同浓度的水浸提液对云南松种子萌发及幼苗生长的化感作用.结果表明:(1)川滇桤木、滇朴、麻栎和山茶四种阔叶树种叶片的水浸提液对云南松种子萌发和幼苗生长表现出低浓度促进,高浓度抑制效应.(2)在测试...     

Anaerobic induced ethanol synthesis in the stems of greenhouse-grown conifer seedlings

Ethanol synthesis was induced in stem segments from greenhouse-grown conifer seedlings by placing them in a N₂ atmosphere at 30 °C for 24 h. Stems from ponderosa pine,Pinus ponderosa Dougl. ex Laws., sugar pine,Pinus lambertiana Dougl., Pacific silver fir,Abies amabalis Dougl. ex Forbes, and lodgepole pine,Pinus contorta Dougl. ex Loud, produced the highest quantities of ethanol. This group also had the smallest and slowest growing stems. Within each of these species the amount of ethanol produced was inversely related to the stem volume. Stems from western hemlock,Tsuga heterophylla (Raf.) Sarg., grand fir, Abies grandis Dougl. ex Forbes, Douglas-fir,Pseudotsuga menziesii (Mirb.) Franco, and western redcedar,Thuja plicata Donn ex D. Don, all produced equivalent but low ethanol concentrations. These species had the largest and fastest growing stems. In this group only grand fir exhibited an inverse relationship between ethanol concentrations and stem volume. The relative amounts of ethanol synthesized by stems from Douglas-fir, western hemlock and western redcedar seedlings were not the same as subsequently observed in logs from mature trees of the same species under field conditions. Differences in the anaerobic environments for the two stem types could have affected the quantities of ethanol produced. The observed high amounts of ethanol produced by the stems from pine species were discussed in terms of their ability to handle periods of anaerobic stress or hypoxia.     

What happens to the mycorrhizal communities of native and exotic seedlings when Pseudotsuga menziesii invades Nothofagaceae forests in Patagonia,Argentina?

Pseudotsuga menziesii is one of the most widely planted conifers in the Patagonian Andes of Argentina, having invading characteristics that are broadly reported. We studied the mycorrhizal status of seedlings along six Nothofagaceae + P. menziesii invasion matrices to investigate their role in the invasive process, according to these hypothesis: a) The abundance and richness of EM will be higher in seedlings grown in their own soil; b) In the presence of native EM inoculum, the invasive plant will be associated with generalist mycorrhizae (EM and/or AM), c) AM associations will be more abundant in P. menziesii seedlings grown in Interface or native forest soils, d) Mycorrhizal community differences between treatments will alter host fitness (growth and nutritional parameters). Seedlings from Nothofagus dombeyi, N. antarctica, Lophozonia alpina, L. obliqua and Pseudotsuga menziesii were set up in a soil-bioassay that included soils from non-invaded Nothofagaceae forests, pure P. menziesii plantations, and the interface between both. Pseudotsuga menziesii seedlings showed a decreasing, although never null, ectomycorrhizal (EM) colonization pattern from plantations to non-invaded forests, mainly with exotic EM species. Hebeloma mesophaeum and Wilcoxina sp. 1, two EM species with cosmopolitan distribution, were found to be shared by both tree species. Hebeloma hiemale and Wilcoxina sp. 1, common mycorrhizal partners of P. menziesii in Patagonia although not registered from Nothofagaceae forest, were found to be associated with N. antarctica, being the first report for both fungal species. Pseudotsuga menziesii seedlings showed the ability to form different arbuscular mycorrhiza (AM) colonization types (Paris-, Arum-, Both- and Intermediate-types) depending on the treatments, with significantly higher presence of Intermediate-type in the Interface treatment, where colonization was low. The shared EM species and the presence of different AM colonization types imply enhanced possibilities for invasive P. menziesii seedlings establishment and development. Seedling features and EM colonization rates evidenced that P. menziesii invasion could produce maladaptation (defined as a relative decline in host fitness due to altered mycorrhizal communities from native settings) of mycorrhizal communities, seriously injuring native ecosystem.