Leptographium pini-densiflorae sp. nov. from Japanese red pine

ALeptographium species was isolated from deadPinus densiflora at six sites in Japan. The fungus is morphologically most similar toL. lundbergii but could be distinguished from that species by its short stipes, primary branches of conidiophores, and conidia with a rounded to sub-truncate base. In addition, the colony morphology, growth rate and tolerance to the antibiotic cycloheximide of theLeptographium species andL. lundbergii differed markedly. Here we describe the fungus as a new species,Leptographium pini-densiflorae. Contribution No. 144, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Grosmannia and Leptographium spp. associated with conifer-infesting bark beetles in Finland and Russia, including Leptographium taigense sp. nov.

Species of Grosmannia with Leptographium anamorphs include important forest pathogens and agents of blue stain in timber. They are commonly found in association with forest pests, such as bark beetles. During a survey of ophiostomatoid fungi in eastern parts of Finland and neighboring Russia, species belonging to the genus Grosmannia were isolated from 12 different bark beetle species infesting Picea abies and Pinus sylvestris, the most economically important conifers in the region. Identification of these fungi was based on morphology, DNA sequence comparisons for three gene regions and phylogenetic analyses. A total of ten taxa were identified. These belonged to six different species complexes in Grosmannia. The phylogenetic analyses provided an opportunity to redefine the G. galeiformis-, L. procerum-, L. lundbergii-, G. piceiperda-, G. olivacea- and G. penicillata-complexes, and to consider the species emerging from the survey within the context of these complexes. The species included G. galeiformis, G. olivacea, L. chlamydatum, L. lundbergii, L. truncatum and a novel taxon, described here as L. taigense sp. nov. In addition, species closely related to G. cucullata, G. olivaceapini comb. nov., G. piceiperda and L. procerum were isolated but their identity could not be resolved. The overall results indicate that the diversity of Grosmannia species in the boreal forests remains poorly understood and that further studies are needed to clarify the status of several species or species complexes.     

Interactions of Hylastes species (Coleoptera: Scolytidae) with Leptographium species associated with loblolly pine decline

Hylastes spp. (Coleoptera: Scolytidae) were evaluated as potential vectors of Leptographium spp. fungi. Bark beetles were trapped from stands ofloblolly pine, Pinus taeda L., exhibiting a range of decline symptoms in central Alabama. Under controlled conditions, field-collected adult Hylastes salebrosus Eichoff (Coleoptera: Scolytidae) and Hylastes tenuis Eichoff (Coleoptera: Scolytidae), which had been surface-sterilized and inoculated with Leptographium terebrantis Barras & Perry and Leptographium serpens (Goid.) Wingfield, transmitted the fungi into 100% of wounded and unwounded loblolly root sections with which they were confined. None of the sterilized and uninoculated beetles transmitted any Leptographium spp. to roots. Significantly more H. salebrosus and H. tenuis brood emerged from roots infected with Leptographium species than from sterile roots, indicating an enhancement of Hylastes reproduction.     

Leptographium wushanense sp. nov., associated with Tomicus armandii on Pinus armandii in Southwestern China

Leptographium wushanense sp. nov., which is associated with Tomicus armandii, is described based on molecular sequence data and morphological characters. The phylogenetic analyses based on ITS2-partial LSU rDNA region, β-tubulin and elongation factor 1-α genes showed that L. wushanense formed a well-supported clade and was closely related to L. conjunctum and L. yunnanense, and then nested within L. lundbergii complex. The species is characterized that its conidiophores were longer than those of L. yunnanense and shorter than those of L. conjunctum, while its conidia were larger than those of L. conjunctum and smaller than those of L. yunnanense. Furthermore, the colonial growth of L. wushanense is faster than those of L. conjunctum and L. yunnanense at 25 °C on 2% MEA. Both molecular data and morphological comparison confirmed the placement of the new species in genus of Leptographium.     

Leptographium sinoprocerum sp. nov., an undescribed species associated with Pinus tabuliformis-Dendroctonus valens in northern China

During a study of ophiostomatoid fungi associated with the invasive pest Dendroctonus valens in the Pinus tabuliformis ecosystem in northern China, a multigenic (ITS2-LSU, beta-tubulin and EF1-alpha) phylogenetic analysis and examination of morphological features revealed in addition to Leptographium procerum the occurrence of an undescribed species. The new species, Leptographium sinoprocerum, belongs to the L. procerum-L. profanum clade. Both L. procerum and L. sinoprocerum are similar to each other and occur sympatrically in the ecosystem studied. Nevertheless L. sinoprocerum can be distinguished from L. procerum by shorter conidiophore stipes arising from both submerged and aerial hyphae, slightly more oblong conidia, a granular ornamentation on the submerged hyphae and dark olivaceous colonies on MEA.     

Leptographium terebrantis inoculation and associated crown symptoms and tree mortality in Pinus taeda

Leptographium terebrantis has been implicated as a contributing factor of P. taeda decline and mortality over the past several decades. We examined the potential of L. terebrantis to cause decline symptoms and determined the relationship between pathogen spread and the formation of new sapwood. The study was undertaken in a 13-y-old P. taeda plantation using artificial inoculations of fungal-colonized, sterilized toothpicks. We found that L. terebrantis was not only re-isolated from dying inoculated trees but caused decline symptomology and mortality at a high inoculum density. It was found that 20% mortality and severe growth loss among surviving trees occurred with L. terebrantis infection at the high density. At lower inoculum densities, trees produced a complete ring of new sapwood that appeared to sustain tree physiology. This suggests that management practices in P. taeda plantations which minimize bark beetle infestation and pathogen inoculum densities allow adequate sapwood function for sustained growth.     

Leptographium pruni, sp. nov. from bark beetle-infested Prunus jamasakura in Japan

Leptographium species are anamorphs of Ophiostoma, commonly isolated from conifer. There are, however, a small number of these fungi that have been collected from angiosperm hosts. In this study, we describe Leptographium pruni, sp. nov. isolated from the bark of Prunus jamasakura infested by the bark beetle Polygraphus ssiori. This new species is unusual in having a distinct Sporothrix synanamorph with ramoconidia. No evidence of a teleomorph was found, but a high level of tolerance to the antibiotic cycloheximide and the presence of a Sporothrix synanamorph suggest that L. pruni is an Ophiostoma anamorph. Analysis of sequence data for the domain 1 region of the LSUrDNA operon also supports the phylogenetic relationship of L. pruni with Ophiostoma. In addition, sequence data suggest that L. pruni is related to other species of Leptographium rather than Pesotum species with distinct Sporothrix synanamorphs.     

华山松大小蠹共生真菌对华山松木质部危害的解剖学研究

通过对野外和人工接种条件下,华山松大小蠹（Dendroctonus armandi)共生直菌（Leptographium terebrantis)对寄主华山松木质部危害的解剖学研究。结果表明,华山松大小蠹共生真菌随华山松大小蠹入侵健康寄主华山松木质部组织,真菌菌丝首先在其木质部树脂道内发育,分解木质部树脂道泌脂细胞,堵塞树脂道;通过菌丝在木质部交叉场薄壁细胞内及管胞细胞间和管胞细胞内的扩展,使寄主华山松树脂代谢,抗性物质代谢和水分代谢紊乱,木质部边材组织蓝变。     

Ethylene production by loblolly pine seedlings associated with water stress

Effects of water stress on production of ethylene and its precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), by loblolly pine ( Pinus taeda L.) seedlings from a Texas drought-hardy and a Virginia Coastal Plain source were investigated. Ethylene production rates in needles from the Virgnia source increased slightly with initial stress (-1.3 MPa), declined until water potential reached -1.6 MPa and then increased sharply at -2.5 MPa. The ethylene production rates in needles from the Texas also increased slightly with initial stress, then decreased with decreasing water potential. Ethylene production by root tissue was two to three times higher than needle tissue and decreased with decreasing water potential. ACC concentrations in needles of both seed sources decreased as water potential began decreasing. Below -1.4 MPa, ACC levels started increasing (Texas source) or remained constant until -2.8 MPa (Virginia source) at which time its level increased three-fold. Mean ACC levels in root tissue [122 nmol (g dry weight)⁻¹] were slightly higher than the mean levels in the needle tissue [92 nmol (g dry weight) ⁻¹]; roots apparently were more efficient in converting it to ethylene since ethylene production was two to three times higher than needle tissue. The modulation of ethylene synthesis by ACC synthase and ethyleneforming enzyme appeared to be influenced by stress level, organ and seed source.     

Trichoderma songyi sp. nov., a new species associated with the pine mushroom (Tricholoma matsutake)

A new species, Trichoderma songyi, was found to be associated with the pine mushroom (Tricholoma matsutake) in Korea. This species was isolated from three different substrates: Tricholoma matsutake basidiomata, as well as roots of Pinus densiflora and soil in the fairy ring. Based on its molecular and phenotypic characteristics, we demonstrate that Trichoderma songyi is unique and distinguishable from closely related species. We performed phylogenetic analyses based on two molecular markers, the genes for both translation elongation factor 1-alpha and the second largest subunit of RNA polymerase II. Phylogenetic analyses showed that Trichoderma songyi is closely related to Trichoderma koningii aggregate and Trichoderma caerulescens. Morphologically, Trichoderma songyi can be distinguished from these closely related taxa by its growth rates, colony morphology on PDA in darkness, and coconut-like odour. Due to the economic importance of the pine mushroom, the relationship between Trichoderma songyi and Tricholoma matsutake should be studied further.     

Fungi associated with the southern pine beetle: avoidance of induced defense response in loblolly pine

Summary Loblolly pines (Pinus taeda) are rapidly killed by colonizing southern pine beetle (Dendroctonus frontalis). The female beetles carry two species of fungi (Ceratocystis minor var. barrasii and an unnamed basidiomycete) within a mycangium. The insects are also frequently associated with a blue-staining form of C. minor. These fungi are inoculated into the tree during colonization. The tree has an induced defensive response that involves resin soaking and necrosis of affected tissue isolating the invading organlsms. The blue-staining fungus stimulates formation of this response in the tree, but the two mycangial fungi do not. These results suggest that the beetles are closely associated with two highly pathogenic fungi that do not stimulate one of the critical components of tree defense.     

Leptographium tereforme sp. nov. and other Ophiostomatales isolated from the root-feeding bark beetle Hylurgus ligniperda in California

The redhaired pine bark beetle Hylurgus ligniperda (F.) is native to Europe but was discovered in Los Angeles, California, in 2003. This root-and stump-feeding beetle is a common vector of Ophiostomatales, which are potential tree pathogens or causes of blue stain of conifer sapwood. In this study Ophiostomatales were isolated on a cycloheximide-amended medium from 118 adult H. ligniperda collected from infested logs of Pinus halepensis and P. pinea at two sites in California. In total eight species of Ophiostomatales were identified and seven species that occasionally were isolated were unidentified. The most frequently isolated species were Ophiostoma ips and Grosmannia galeiforme, which were isolated respectively from 31% and 23% of the 118 beetles. The other species isolated included O. piceae (isolated from 9% of the beetles), O. querci (8%) and Leptographium tereforme sp. nov. (6%). Grosmannia huntii, L. serpens, three Sporothrix species, O. floccosum, O. stenoceras, two unidentified Hyalorhinocladiella sp. and a sterile fungus each were isolated from fewer then 5% of beetles. Most of the identified species already were known in USA and have been found in association with H. ligniperda in other countries. However the new species, L. tereforme, and G. galeiforme were recorded from USA for the first time, and this is the first report of L. serpens from western North America.     

Obolarina persica sp. nov., associated with dying Quercus in Iran

A new species, Obolarina persica, is described from Iran. It is widely associated with dying Quercus brantii, on which it produces charcoal-like stromata. The fungus described herein differs from the other described species, Ob. dryophila, primarily in its much larger ascospores.     

Xenorhabdus japonicus sp. nov. associated with the nematode Steinernema kushidai

A new species, Xenorhabdus japonicus, is proposed as the bacterial symbiont of Steinernema kushidai isolated from field soil in Shizuoka Prefecture, Japan. Xenorhabdus japonicus could be distinguished phenotypically and genetically from other Xenorhabdus spp. The type strain of the species, SK-1, a Gram-negative, facultative anaerobe and peritrichously flagellated rod, has colonies with primary and secondary forms. The strain can be differentiated from the type strain of Xenorhabdus nematophilus by several characters, including the formation of arginine dehydrolase, phenylalanine deaminase and lysine decarboxylase, the assimilation of inosine and L-proline and acid production from inositol. The major cellular fatty acids are 16:0, cyclo 17:0 and 18:1. The ubiquinone system is Q-8. The G+C content of DNA is 45.9 mol%. The DNA of strain SK-1 has 20 to 58% homology with that of the type strains of other Xenorhabdus spp.Y. Nishimura, A. Hagiwara and T. Suzuki are with the Department of Applied Biological Science, Science University of Tokyo, Noda 278, Japan, and SDS Biotech K.K., Tsukuba Technology Centre, Tsukuba 300-26, Japan     

Methylobacillus arboreus sp. nov., and Methylobacillus gramineus sp. nov., novel non-pigmented obligately methylotrophic bacteria associated with plants

Two newly isolated obligate methanol-utilizing bacteria (strains Iva^T and Lap^T) with the ribulose monophosphate pathway of C₁ assimilation are described. The isolates are strictly aerobic, Gram negative, asporogenous, motile rods multiplying by binary fission, mesophilic and neutrophilic, synthesize indole-3-acetate. The prevailing cellular fatty acids are straight-chain saturated C_16:0 and unsaturated C_16:1 acids. The major ubiquinone is Q-8. The predominant phospholipids are phosphatidylethanolamine, phosphatidylglycerol and cardiolipin. Ammonia is assimilated by glutamate dehydrogenase. The DNA G+C contents of strains Iva^T and Lap^T are 54.0 and 50.5 mol% (T_m), respectively.Based on 16S rRNA gene sequence analysis and DNA–DNA relatedness (38–45%) with type strains of the genus Methylobacillus, the novel isolates are classified as the new species of this genus and named Methylobacillus arboreus Iva^T (VKM B-2590^T, CCUG 59684^T, DSM 23628^T) and Methylobacillus gramineus Lap^T (VKM B-2591^T, CCUG 59687^T, DSM 23629^T).The GenBank accession numbers for the 16S rRNA gene and mxaF gene sequences of the strains Iva^T and Lap^T are GU937479, GU937478 and HM030736, HM030735, respectively.