Lignin-degrading enzymes from a pathogenic canker-rot fungus Inonotus obliquus strain IO-B2.

Inonotus obliquus is a pathogenic fungus found in living trees and has been widely used as a traditional medicine for cancer therapy. Although lignocellulose-degrading enzymes are involved in the early stages of host infection, the parasitic life cycle of this fungus has not been fully understood. In this study, we aimed to investigate the activities of laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP) from I. obliquus cultivated in Kirk's medium. The fungus was subjected to genome sequencing, and genes related to wood degradation were identified. The draft genome sequence of this fungus comprised 21,203 predicted protein-coding genes, of which 134 were estimated to be related to wood degradation. Among these, 47 genes associated with lignin degradation were found to have the highest number of mnp genes. Furthermore, we cloned the cDNA encoding a putative MnP, referred to as IoMnP1, and characterized its molecular structure. The results show that IoMnP1 has catalytic properties analogous to MnP. Phylogenetic analysis also confirmed that IoMnP1 was closely related to the MnPs from Pyrrhoderma noxium, Fomitiporia mediterranea, and Sanghuangporus baumii, which belong to the same family of Hymenochaetaceae. From the above results, we suggest that IoMnP1 is a member of MnPs.

Pectin decomposition at the early stage of brown-rot decay by Fomitopsis palustris.

The sapwood of Japanese cedar (Cryptomeria japonica D. Don) was decayed by the brown-rot fungus Fomitopsis palustris under bright and dark conditions. Scanning electron microscopy revealed the presence of mycelia inside the wood even after 1 week from the start of fungal exposure. Moreover, holes were observed in the torus after fungal exposure. Ruthenium red staining revealed that the pectin in pits was largely absent for 3 weeks. These events occurred before the mass loss of wood samples was confirmed at the early stage. Moreover, FpPG28A was more highly expressed at the hyphal front on a pectin-containing medium under dark conditions compared with bright conditions. This up-regulation under dark conditions indicated that the pectin decomposition ability was promoted inside the wood where light could not reach. In conclusion, we suggest that the brown-rot fungus completed its hyphal expansion within the wood via pectin decomposition in pits before holocellulose decomposition.

Geographic and longitudinal variations of anatomical characteristics and mechanical properties in three bamboo species naturally grown in Lombok Island, Indonesia.

The anatomical characteristics (fiber length and fiber area) and mechanical properties (modulus of elasticity, modulus of rupture, compressive strength, tensile Young's modulus, and tensile strength) of Bambusa vulgaris, Bambusa maculata, and Gigantochloa atter, naturally growing at four different sites in Lombok Island, Indonesia, were examined for evaluating geographic and longitudinal variations by mixed-effects modeling to effectively utilize bamboo culm resources for structural materials. We found geographic and longitudinal variations of bamboo culm properties in these three species. Based on the results, we concluded that, for utilization of bamboo culm as a structural material, variation of individual culm rather than site, and longitudinal variations should be considered for Bambusa species and G. atter, respectively.

Estimating available unused dead wood materials for heat generation in Mongolia: how much coal can unused dead wood materials substitute?

In this study, we estimated the technoeconomic availability of three types of dead trees, namely commercially fallen, normally fallen, and standing, in Mongolian subgroups. For dead trees of three major Mongolian tree species (Siberian larch, Scotch pine, and Asian white birch), lumber, firewood, and unused material as sources of energy were quantified and operational costs (marking, felling, skidding, transporting, loading/unloading, processing, and stumpage prices) were estimated. As a result, most Mongolian subgroups were profitable and suitable for the harvest of unused materials. Moreover, unused materials of dead trees can substitute nearly 5.45 million tons of coal, although it is not sufficient to meet the 0.6 years of coal demand across Mongolia. However, in some places, unused dead wood materials can completely substitute coal for decades. Therefore, although the heat utilization of woody biomass is not suitable for Mongolia as a whole, it is feasible in specific regions where forest resources are abundant, such as some Mongolian sub-provinces. Promoting the use of dead trees can reduce the risk of damage caused by wildfires and pests, which are serious problems in Mongolia, and keep the forests healthy. Furthermore, unused materials can generate new income opportunities, and the forest land can be well prepared by removing dead trees to promote planting for sustainable forest management. Finally, dead trees can be used as a resource until transition to sustainable forests with living trees.

Physical and mechanical properties of wood and their geographic variations in Larix sibirica trees naturally grown in Mongolia.

We examined the physical and mechanical properties of wood in Siberian larch (Larix sibirica) trees that grow naturally in five Mongolian provenances (Khentii, Arkhangai, Zavkhan, Khuvsgul, and Selenge) and the geographic variations between them. Five trees with stem diameters of 20 to 30 cm at 1.3 m above ground were collected from each provenance. The mean values of the modulus of elasticity (MOE), modulus of rupture (MOR), compressive strength parallel to grain (CS), and shearing strength (SS) ranged from 7.03 to 9.51 GPa, 79.8 to 103.9 MPa, 46.3 to 51.1 MPa, and 10.4 to 13.0 MPa, respectively. Significant differences were found in radial and tangential shrinkage, MOE, MOR, and SS in wood among the five provenances. In addition, juvenile wood had inferior physical and mechanical properties in comparison to mature wood within and among provenances. Furthermore, there were significant differences in all examined properties, except for CS, in mature wood among the five provenances. Higher correlation coefficients were also obtained in mature wood among all mechanical properties, except for SS.

The complete mitochondrial genome sequence of the medicinal fungus Inonotus obliquus (Hymenochaetaceae, Basidiomycota).

Inonotus obliquus is a medicinal fungus in the family Hymenochaetaceae and commonly known as chaga. The sclerotium of this fungus has been used as a traditional medicine for long time. In this study, we present the mitochondrial genome sequence of I. obliquus. The mitochondrial DNA (mtDNA) is 119,110 base pairs in length and contained genes for 58 Open reading frames, 2 ribosomal RNAs, and 30 transfer RNAs. Consequently performed phylogenetic analysis indicates that this fungus is closely related to Sanghuangporus sanghuang which belongs to the same family Hymenochaetaceae. We first reported about the complete mitochondrial genome of fungi belonging to the genus Inonotus.

Proteomic Analysis of Responsive Proteins Induced in Japanese Birch Plantlet Treated with Salicylic Acid.

The present study was performed to unravel the mechanisms of systemic acquired resistance (SAR) establishment and resistance signaling pathways against the canker-rot fungus (Inonotus obliquus strain IO-U1) infection in Japanese birch plantlet No.8. Modulation of protein-profile induced by salicylic acid (SA)-administration was analyzed, and SA-responsive proteins were identified. In total, 5 specifically expressed, 3 significantly increased, and 3 significantly decreased protein spots were identified using liquid chromatography/tandem mass spectrometry (LC/MS/MS) and the sequence tag method. These proteins were malate dehydrogenase, succinate dehydrogenase, phosphoglycerate kinase, diaminopimalate decarboxylase, arginase, chorismate mutase, cyclophilin, aminopeptidase, and unknown function proteins. These proteins are considered to be involved in SAR-establishment mechanisms in the Japanese birch plantlet No 8.