Phytochemical bioprospecting, antioxidant, antimicrobial and cytotoxicity activities of saline extract from Tithonia diversifolia(Hemsl) A.Gray leaves

Objective:To evaluate antimicrobial and antioxidant properties of saline extract from Tithonia diversifolia leaves by phytochemical bioprospecting,and investigate its safety against animal cells.Methods:The saline extract was prepared,with NaCl(0.15 M),by constant stirring of the dried and pulverized leaves,followed by volume reduction by lyophilization.The extract was phytochemical characterized using ultra-performance liquid chromatography,and total phenol and flavonoid analysis also was performed.The antioxidant capacity was determined through DPPH*radical,the antimicrobial property was evaluated against standard bacteria and fungi,and the viability assays were performed against mice splenocytes.Results:Fifteen compounds were identified belonging to two main classes terpenoids and phenolics.The extract showed 22.185 mg GAE/g of total phenolic compounds and 3.220 mg QE/g of flavonoid.Moreover,extract showed higher antioxidant ability similar to butylated hydroxytoluene a standard molecule[(3.042±0.019)mg AAE/g and(4.12±0.10)mg AAE/g to saline extract and butylated hydroxytoluene,respectively].The antimicrobial assays demonstrated that the extract had a significant antifungal potential against Candida species and could be used with safety against mice splenocytes,in concentrations lower than 50μg/mL,promoting higher proliferation in these cells.Conclusions:Saline extract from Tithonia diversifolia leaves presents potential antioxidant,antifungal properties and induces immunostimulation in mice splenocytes.

The disease resistance potential of Trichoderma asperellum T-Pa2 isolated from Phellodendron amurense rhizosphere soil

To promote the application of Trichoderma,many countries have collected Trichoderma resources.In the present study,nine isolates were isolated from a rhizosphere soil of Phellodendron amurense and were identified as three species:Trichoderma brevicompactum(one isolate),T.asperellum(two isolates),T.atroviride(six isolates).Dual culture experiments showed that T.asperellum T-Pa2 grew fast and produced the best inhibition rates against six tested pathogens(80.25–91.65%)via competition and mycoparasitism.Populus davidiana×P.alba var.pyramidalis Louche(PdPap poplar)was treated with T-Pa2,which increased the catalase activity,nitrate reductase activity,and content of osmosis molecules significantly(P<0.05).Meanwhile,induction by T-Pa2 increased the resistance of PdPap poplar against Alternaria alternata via modulating the expression of salicylic acid,jasmonic acid,and auxin transduction pathway genes.The results will form the basis for the collection and application of biocontrol agents in forestry.

Papiliotrema flavescens colonized in biochars inhibits wheat crown rot and Fusarium head blight

Biochar,a known soil amendment,has been found to alleviate plant or soil-borne diseases.However,the related mechanisms are poorly understood,especially from the perspective of microbes colonizing in raw biochar.In this study,laboratory studies,including isolation,adsorption,antifungal test,were employed to investigate biological characteristic of a fungus isolated from aging biochars(peanut shell biochar,rice husk biochar and bamboo biochar),as well as antimicrobial mechanisms on Fusarium species which cause wheat crown rot and Fusarium head blight(FHB).Furthermore,the field trial was conducted to investigate the effect of this fungus on spikelet disease rate and crop yield.The results were as follows:the isolated fungus was identified as Papiliotrema flavescens(P.flavescens),which was confirmed from ambient air,and its properties were characterized,such as the optimal growth pH and the growth curve.The mixed action of 1×10^(6)cells/mL P.flavescens and 1×10^(6)cells/mL Bacillus subtilis(B.subtilis)had the best antifungal effect,reaching an antifungal rate of 86.5%.The P.fla-vescens exerted antifungal effects through potential competition among nutrition,space,and parasitism,not from producing antifungal substances.Results from the field trial showed that the presence of P.flavescens could reduce the spike disease rate by 43.2%and increase the yield by 34.5%.In summary,the present study provides novel evidence about microbes from aging biochars that can prevent wheat crown rot and FHB.