| Festuca spp.is widely distributed in temperate regions of the world and has important economic and ecological value.The endophytic fungi of the genus Epichlo? can form symbiosis with some plants of this genus,so that they have strong growth and stress resistance characteristics,but the mechanism still needs to be further studied.In this study,F.arundinacea,F.sinensis,F.pratensis,F.stapfii,F.rubra and F.ovina,collected from Yunnan,Guizhou,Sichuan and Gansu provinces,were used as test materials.We determined the endophyte infection rate and diversity,dectected fungal viruses,compared the C,N and P content of plants with and without endophyte,with a view to providing basic data for further research and utilization of the symbiosis of fescue grass and Epichlo? endophyte.The main findings are as follows:1.In the 6 kinds of grasses,F.pratensis and F.rubra were not infected by endophytes.F.sinensis had the highest infection ratio,which was 35.4%,and the infection ratio of F.stapfii was 27.4%.The infection ratios of both F.arundinacea and F.ovina were under 10%.The infection ratio was positive correlation with both precipitation and altitude,while,had a negative correlation with temperature.2.The two fungi isolated methods of cutting and smearing were compared,respectively in PDA,MEA,PSA and FA.The isolated rates obtained by the two isolated methods were 9.07% and 8.61%,respectively.The separation rates were the highest in PDA and PSA media,both at 10.0%,followed by MEA at 9.57%,and FA at the lowest,at 5.8%.3.The isolated endophytes of the genus Epichlo? were clustered according to morphological characteristics,and the endophyte symbiotic with F.stapfii were initially identified as E.starrii;the endophytes symbiotic with F.arundinacea and F.ovina were initially identified as E.typhina;and endophytes symbiotic with F.sinensis had a certain morphological diversity and can be divided into 4 branches,one of which was E.sinensis,and the taxonomy of the remaining 3 branches still need to be further researched.4.We detected mycoviruses in endophytic fungus that separated from the 4 fescue grasses by molecular methods,and all the dsRNA(double-stranded RNA)detection results of them were negative,which means that there were no mycoviruses infection in these 32 endophyte strains.5.Using the method of duel-culture,the inhibited effects of three endophytes E.starrii,E.typhina and E.sinensis on two plant pathogenic fungi,Stemphylium sp.and Bipolaris sp.were determined.The results showed that E.typhina had the highest inhibiting rate of 25.0% for Stemphylium sp;E.sinensis had the highest inhibiting rate of 24.0% for Bipolaris sp.6.The results of the determination of total nitrogen(TN),total phosphorus(TP)and organic carbon(OC)content of 4 species of fescue showed that compared with grasses without endophyte,grasses infected by endophyte of F.arundinacea,F.sinensis,F.stapfii and F.ovina had higher TN content,among which the TN content of F.arundinacea and F.ovina were significantly higher(P <0.05),increasing by 22.3% and 11.6%,respectively.The TP and OC content of the 4 species of fescue grasses were also increased significantly,among which the TP content could be increased by 26.5% at the highest;the OC content could be increased by 1.9%-2.8%.Endophyte reduced the C:N and C:P of the 4 fescue species tested,of which the C:N of F.sinensis and F.arundinacea were decreased by 16.0% and 8.6%,respectively(P <0.05);C:P was decreased the most by 19.3%.The effect of endophyte on the N:P of the 4 fescue species tested varied according to species.Compared with grasses without endophyte,the N:P of F.arundinacea and F.stapfii were decreased by 11.1% and 10.1%,respectively,while the N:P of F.sinensis and F.ovina were increased by 13.4% and 4.4%,respectively. |
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