Diversity Of Endophytic Fungi In Wheat (Triticum Aestivum L.) And Their Relationship With The Host

Endophytic fungi are widely distributed in plant tissues and organs, and have formed a kind of complex and special relationship after long-term coexistence with the host. They can affect the growth and development, the evolution process and ecological adaptability of the host. So it is significant to study the diversity of endophytic fungi and their relationship with the host systematically. Wheat is the second-largest food crop in China. Study on the wheat-endophyte interaction has a very important significance for the utilization of beneficial endophytes, the control of the potential harmful endophytes, and therefore, the improvement of wheat production.Isolation methods of endophytic fungi in the organs of wheat were firstly optimized in this research. Diversity and distribution of endophytic fungi in each organ and growth period of wheat were studied, which was compared with the diversity of wheat rhizospherical fungi. Endophytic fungi in seedling wheat cultivated under aseptic condition were isolated to reveal the infection pathway. The diversity of wheat endophytic fungi in wheat cultivated under different soil conditions was explored. The influence of endophytic fungi to the growth of wheat was preliminarily studied.1.3% NaClO and 75% alcohol were used as the disinfectants in combination. The disinfecting time of each organ was optimized. PDA medium was selected for the isolation of the endophytic fungi in wheat.2. It was found that endophytic fungi in each organ of wheat were different. Isolated rate of endophytic fungi in roots was the highest, which was 25.60%, and that of leaves and stems were 16.37% and 11.92% respectively. Isolating rates in the roots, stems and leaves of wheat rose with the maturation of the wheat. But in the Over-wintering stage, the rates of each part fell in different extent, which indicated that the quantity of endophytic fungi could be influenced by low temperature.3. Eleven genera of endophytic fungi of wheat were isolated and identified. Alternaria, Penicillium, Bipolaris, Fusarium, Rhizopus and Trichoderma were the advantage fungi. And Alternaria, Penicillium, Rhizopus and Fusarium could be isolated in each growth period of Wheat. Alternaria, Bipolaris and Fusarium are potential pathogenic fungi. A fungus of Acremonium sp. was isolated in wheat root of seedling stage, which was found symbiotic with gramineous grasses.4. Comparison with rhizospherical fungi revealed certain relationship between endophytic and soil fungi, but the difference was also obvious, which indicated that other sources existed for the endophytic fungi in the wheat plants. Further analysis of endophytic fungi in wheat seedlings cultivated under aseptic condition indicated that endophytic fungi could infect through the seeds when the seeds germinated, or through the surface of the roots, stems or leaves.The relationship of the endophytic fungi isolated and the host wheat was studied preliminarily. No significant influence on the growth of the host was found. It is necessary to make further study of the relationship of the endophytic fungi and the host.Diversity of endophytic fungi in each organ and each growth period of wheat was studied systematically. Source and distribution of endophytic fungi in wheat were revealed. And the influence of endophytic fungi to the growth of wheat was studied preliminarily. These conclusions set the foundation for the further study on endophytic fungi of wheat and their relationship with the host, and provided theoretical basis for the application of endophytic fungi in agriculture.