Reseach On The Ecological Functions Of Endophytic Chaetomium In Wheat

Endophytic fungi are generally those fungi that live inside the plant tissues without causing obvious symptoms for their whole or part life cycle, which almost exist in all plants. They live for a long time in the plants which offer stable micro-ecological environment, and have great significance for the growth and ecological distribution of plant. Endophytic fungi have important value in improving plant resistance, biological control of plant diseases and insect pests, promoting plants’ growth and producing bioactive substances, etc. The Chaetomium fungus is a kind of important saprophytic fungi and common endophytic fungi of various plants, which has important application value in biological control of plant diseases and degradation of cellulose, etc.This paper studies the phylogenetic relationship, biological characteristics, the ability of using cellulose material and the influences of wheat germination and seedling growth of Chaetomium endophytic fungi isolated from wheat so as to discuss the related ecological functions of Chaetomium endophytic fungi isolated from wheat. The study has very important significance for understanding the life history of Chaetomium endophytic fungi, the relationship with the host wheat and the development and utilization of Chaetomium endophytic fungi.In this paper, the six strains Chaetomium fungi isolated from different tissues of wheat are morphologically identified to explore their phylogenetic relationship, and the cellulolytic ability of the six Chaetomium strains are compared. Then the Chaetomium strain with the best cellulolytic ability is chosen as the research object, and discuss some biological characteristics. Lastly, six strains Chaetomium fungi are studied on the influences of wheat germination and seedling growth.Through the strains identification of the six strains Chaetomium fungi by morphological observation and gene sequencing analysis, the results show that Chaetomium C1, C2, C4, C5 and C6 all belong to Chaetomium globosum, and they have a close genetic relationship in system development. Chaetomium C3 is identified to be Chaetomium indicum.Using cellulose-congo red medium and weight losing test of filter paper, Chaetomium C3 is found the strongest ability to degrade cellulose. And the results about cellulase activity also show that Chaetomium C3 has the highest cellulase activity of the six strains Chaetomium fungi. Studying the growth of Chaetomium C3 on different carbon sources finds that its best carbon source is maltose, and cellulose and starch are also good carbon sources. By some analysis I find that the optimum growth temperature of Chaetomium C3 is the same as the optimal temperature of enzyme production, which is 30℃. And if the temperature is too high or too low, the enzyme activity can be affected and then it is bad for the growth. Using Chaetomium C3 as a test strain for degrading wheat straw, statistics about straw weightlessness rate for three weeks show that the weightlessness rate from the inoculated group with Chaetomium C3 is 16.00%, 21.92% and 29.43%. It is significantly higher than the weightlessness rate from the group without being inoculated any fungi, which is 9.67%, 10.46% and 14.74%. So the result shows that Chaetomium C3 has a certain effect on the degradation of cellulose and wheat straw, and it may complete some of the life cycle in the environment of containing cellulose material by the saprophytic nutrition way.The bacteriostatic experient shows that Chaetomium C3 has obvious inhibition effect on the growth of Curvularia lunata and Fusarium graminearum, and the inhibition effect is not obvious on Rhizoctonia cerealis and Bipolaris sorokiniana, but Helminthosporium maydis is not basically inhibited. There is a preliminary research and analysis about the six strains Chaetomium fungi isolated from wheat influencing the growth of wheat seedling stage. The results show that they have basically no effect on the germination of wheat seeds, but have a certain role in promoting the growth of wheat seedling stage. As for the specific mechanism of promoting growth, further research is needed.