Difference Of Natural Wood-decaying Tolerance Of Betula Platyphylla Suk. And Different Expression Of Wood Rot Gene In Wood Rot Fungi Before And After Decaying Wood

Live stumpage decaying are disadvantages in international forestry production and wood utilization. The study on change of wood component before and after wood rotted and gene different expression of the rot fungi would help to understand the decay mechanism of the wood. In this study, the wood of white birch and 5 wood rot fungi were used as materials, the changes in main chemical components of the wood before and after the wood decayed by rot fungi was systematically analyzed. Different expressed genes of wood rot fungi induced by wood chip were isolated. The relationship between the biological characteristics of several wood rot fungi and their degradation ability to birch wood were discussed. The interaction mechanism between wood rot fungi and major components of the birch wood before and after decayed were investigated according to their change pattern. A environment friendly breeding strategy of the birch with susceptible and resistant characteristics was investigated, which is a selective breeding on the basis of the degradation ability of the fungi and the natural decay resistance of white birch. The major results are as follows:(1) Irpex lacteus, Pholiota adipose, Coriolus versicolor, Fomes fomenta-rius and Piptoporus betulinus were separately used to decay 300 wood samples of white birch from Maoer Shan area for testing natural decay resistance f the white birch. The differences of weight loss of decayed wood between individual trees are statistically significant. They show normal distributions at the population level. The decomposing power of Coriolus versicolor to wood samples is higher than that of Fomesfom entarius and Piptoporus betulinus, while the decomposing power of Irpex lacteus and Pholiota adipose are the weakest ones. The weight loss of decayed wood between Fomes fomentarius and Pholiota adiposa shows significant positive correlation. But the weight loss of decayed wood between Irpex lacteus and Piptoporus betulinus shows highly significant negative correlation.(2) The differences between rotten wood and fresh wood in terms of the main chemical components are compared. Different wood rot fungi has different decaying value in main chemical components of the wood, that means that different wood rot fungi have their own preference on each chemical component of wood.10 susceptible plants and 10 resistant plants were selected by each wood rot fungi based on weight loss rate of decayed wood, that grouped 5 susceptible populations and tolerance populations separately. The difference of decayed wood weight loss was the most significant between corresponding groups.5 tolerance populations could breed for construction wood and plywood. Susceptible population could breed for pulpwood. Susceptible and tolerance birch plants selected by different wood rot fungi mostly were found to be not the same. (3) To divide natural resistance ability of white birch to three levels, such as resistant, susceptible and the moderate by 5 wood rot fungi separately. It provided a convenient comparison method and criterion to judge whether the wood of a birch plant whether or not to resists one of the 5 wood rot fungi in future.(4) After the pearson correlation analysis of major wood chemical components between tolerance and susceptible populations, it was found that the 1% NaOH extraction in wood had negative correlations with the water content and cellulose. The water content and cellulose, benzene-alcohol extraction and total phenol, total phenol and total flavonoids as well as lignin have positive correlations in the wood of susceptible populations. These correlations was consistent with the related characteristics of the corresponding components, as well as with their contents in the both populations.(5) Phenols and flavonoids content in birch wood were tested by spectrophotometry. The wood with higher total phenols and total flavonoids content was hard to be decayed by Fomes fomentarius, and the wood with higher total phenols content was more inappropriate by Piptoporus betulinus. The birch wood powders were tested by GC-MS.11 compounds were discovered. 4,7-methano-1H-indenol-hexahydro,2,2'-[1,2-ethanediylbis (nitrilomethylidyne)] bis-phenol and 3,4,5-trimethoxy-phenol belong to phenols, and trans-3'-Methyl-4-(methylthio)chalcone belong to flavonoids in birch wood.(6) The growth characteristics of 5 wood rot fungi in solid and liquid media were systematically compared with the activities of ligninolytic enzymes and wood-decaying capacities. The wood-decaying capacities of white birch by 5 wood rot fungi were corresponded with the time needed to achieve the fastest growth rate of the fungi in liquid medium; but no obvious correlation with their growth rate or the activities of ligninolytic enzymes. The wood rot fungus with fast growth rate did not really show strong wood-decaying capacity.(7) For the wood decayed by Fomes fomentarius,1%NaOH extraction content was the lowest, and benzene-alcohol extraction was in the middle, and cellulose was the highest, and lignin was lower, but, which has stronger wood-decaying capacity. It means that Fomes fomentarius could be transformed into the best engineering strain for processing raw materials in paper industry.The wood-decaying capacity of Coriolus versicolor was the strongest among all 5 fungi, but the cellulose content in wood decayed by it was lower. It means that Coriolus versicolor was not suitable for bio-assisted paper-making. Meanwhile, Coriolus versicolor could be used for pollutant control since the activities of its MnP and Lac were the highest.The fresh wood of susceptible populations selected by Fomes fomentarius, which 1% NaOH extraction content was in the middle, benzene-alcohol extraction was the lowest, cellulose was highest, and lignin was also the lowest, could be the best raw materials in alkaline pulping process by using alkaline method.(8) The activities of Lip, MnP, Lac could be tested in Pholiota adiposa, which lignin loss rate was higher than the cellulose loss rate in wood decayed by it. At the same time, color of the wood decayed by Pholiota adipose looks white and the decayed wood was difficult to be crushed. Pholiota adiposa should belong to white rot fungus.(9) White rot fungus—Irpex lacteus and brown rot fungus—Piptoporus betulinus were induced by wood powder separately.5 homologous fragments, such as Laccase, etc. were found in Irpex lacteus cDNA fragments,7 homologous fragments, such as pre-mRNA splicing factor syf2, etc. were found in Piptoporus betulinus cDNA fragments. Those fragments all expressed in fungus in different level and devoted for wood decaying.The gene expressed obviously different between white rot fungi and brown rot fungi induced by wood powder of white birch. These differential expression gene fragments would play important roles in the research of wood decay mechanism.