Orendophytic Fungi Isolation From Tephrosia Purpurea And The Study On Secondary Metabolites Of Its Active Strain TPL25

Tephrosia purpurea is a semi-shrub widely distributed in tropical and subtropical areas, which has been an important raw material of traditional herbal formulas, but also an important source of insecticide rotenone ingredients plant. The early studies of our laboratory found that T. purpurea extracts have strong insecticidal activity, and the secondary metabolites of the plant roots, stems, leaves, seeds were systematic studied. The endophytic fungi are generally able to participate in and affect the kind or content of secondary metabolites of host plants, or even a small number of endophytic fungi capable of producing the same or similar secondary metabolites to host plants. Up to now, the role of the endophytic fungi that are associated with T. purpurea remains unclear. Thus, we collected the plant T. purpureaand then isolated the endophytic fungi. Here, we investigated the phylogenetic diversity of endophytic fungi from T. purpurea and evaluated their potential insecticidal and antifungi activity. Then, we isolated and identified chemical components of the active strain. This research is aimed at providing the basis for the further development and utilization with insecticidal plant T. purpurea. Results are as follows:1. Sixty-one endophytic fungi with different colony morphologies isolated from leaves, stems, and roots of T. purpurea. All isolated strains belonged to one of 3 classes including 7 orders by morphology and molecular identification. Of the 61 strains,59 were identified at the genus level.2. The endophytic fungi isolated from T. purpurea were tested by primary and secondaryscreening for their ability against tosix plant pathogenic fungi. We obtained the high active strain TPL25, of which fermentation broth strongly inhibited the growth of Sclerotinia sclerotiorum, P. parasitica var. nicotianae and P. melonisand the inhibitory rate have more than 80%. Then, strain TPL25 was identified as Penicillium griseofulvum by morphological and molecular identification.3. The extracts (40mg/mL) of TPL25 exhibited a good inhibitory effect against the tested pathogenic fungi. The methanol extracts of mycelium and ethyl acetate extracts of fermented liquid showed significant inhibition against S. sclerotiorum. The extracts of strain TPL25 at concentration of 50 mg/mL showed insecticidal activity to Myzus persiace (Sulzer) after treatment with 24 h, wherein the ethyl acetate extract of the broth exhibited most significant insecticidal effect, the virulence regression equation was Y=1.5446 X+2.5788 (R2=0.9998) with the value of LC50 being 36.9 mg/mL. After treatment at concentrations 50 mg/mL,48 h, the extracts of TPL25 against Plutella xylostella (L.) exhibited antifeedant activity, especially ethyl acetate extracts with non-selective antifeedant rate up to 98.1%.4. Seven known compounds (1-7) had been isolated and identified from the extracts of strain TPL25, they were:hexitol (1),9-octadecenoic acid-2,3-dihydroxypropyl ester (2), methyl ?-D-glucopyranoside (3), undine (4), adenosine (5),1,2-Benzendicar-boxylic acid bis (2-methylpropyl) ester(6),2',3'-dihydrosorbicillin(7). Among these compounds, compound 6 showed weak activity against S. Sclerotiorum, compound 1 and compound 7 exhibited some insecticidal activity to M. persiace (S.).