Studies On Endophytic Fungis From Juglans Regia L. And Their Secondary Metabolites' Activity

In this paper, 27 kinds of strains isolated from roots, stems, fruits and leaves of Walnut (Juglans regia L.). 8 strains were from roots, which occupy 29.6% in 27 strains; 11 strains were from stems which occupy 40.7% in 27 strains; 4 strains were from fruits or leaves, respectively, which occupy 14.8% in 27 strains. It showed that the species and distribution of the endophytic fungus varied in different parts of Juglans regia L.Antimicrobial activity of 27strains endophytic fungi and their secondary metabolites was screened with 5 kinds of pathogenic fungi as tested bateria; wheat as allelopathy activity tested seed. We chose R8F and R9G as our target strains according to results of activity screening results. R9G strain which was isolated from the roots of Juglans regia L. was shown to be inhibitory to 14 typical pathogenic fungi, thereinto inhibiting rate at 50% and above were 6 strains which occupy 42.9% in 14 strains, and the inhibiting rate for 14 strains pathogenic fungi all above 39%. The inhibition of endophytic fungi fermente from R9G to growth of young roots and buds of wheat was 82.60 % and 63.64%. These showed that R9G was shown to be inhibitory to tested pathogenic fungi and allelopathy activity to wheat.To study the antimicrobial activity of the fermentation products and its extracts. The fungus fermented in liquid PDA culture medium. The results showed that, The extracts of fermentation all have different range activity to 31 kinds of pathogenic fungi, the inhibiting effect of the phases is acetyl acetate, butanol and residue from strong to weak.The inhibiting rate of acetyl acetate phase to pathogenic fungi at 50% and above were 28 strains which occupy 90.32% in 31 strains, at 70% and above were 21 strains which occupy 67.74% in 31 strains,at 90% and above were 5 strains which occupy 16.13% in 31 strains. These showed that the mainly inhibiting substance of R9G were in acetyl acetate phase. The extracts of acetyl acetate has different inhibiting effect on 5 species of tested bacteria, The variance analysis of group mean showed that the mean difference was significant at 0.05 level,but the multiple comparisons was not significant at 0.05 level. Different concentration of acetyl acetate extract has different inhibiting effect on 31 kinds of pathogenic fungus. The variance analysis and multiple comparisons of group mean all showed that the difference was significant at 0.05 level.R9G strain with antimicrobial activity was fermented in liquid PDA culture medium, and extracted to give 35g crude extract.11 compounds were obtained from the acetyl acetate extract of R9G by silica gel column chromatography, C18 column chromatography, Sephadex LH-20 column chromatography, thin layer preparation chromatography and re-crystallization. On the basis of chemical reaction and spectral data analyses(UV,MS,IR,NMR,DEPT,HMBC and HMQC), 2 compounds were elucidated as: compound A was 3β-hydroxy-5α-cholestan and compound oil B was oleic acid.