The Combination of Achnatherum inebrians Extracts and Soil Microorganisms Inhibited Seed Germination and Seedling Growth in Elymus nutans

In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts from aboveground and belowground parts of A.inebrians significantly inhibited the germination rate,germination potential,germination index,vigor index,seedling height,root length,and fresh weight of E.nutans,but increased malondialdehyde content,catalase,peroxidase and superoxide dismutase activity of E.nutans seedlings(p<0.05).The allelopathy of aqueous extracts of the aboveground parts of A.inebrians was stronger than that of the pre-cipitates.Aqueous extracts of the aboveground parts of A.inebrians decreased seed germination rate,germination potential,germination index,vigor index,seedling length,root length,and seedling fresh weight by 10.45%-74.63%,24.18%-32.50%,19.03%-73.36%,37.83%-88.41%,21.42%-53.14%,2.65%-40.21%,and 20.45%-61.36%,respectively,and malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity increased by 8.09%-62.24%,27.83%-86.47%,22.90%-93.17%,and 11.15%-75.91%,respectively.The above indexes were higher in live soil than in sterilized soil.Soil microorganisms increased the allelopathy of A.inebrians.The seed germination rate,germination potential,germination index,vigor index,seedling length,and seedling fresh weight of E.nutans planted in live soil decreased by 8.22%-48.48%,10.00%-51.85%,8.19%-53.26%,16.43%-60.03%,12.91%-28.81%,and 9.09%-22.86%compared with sterilized soil,respectively.Malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity of E.nutans planted in live soil increased by 53.91%-81.06%,15.71%-57.34%,33.33%-86.31%,and 9.78%-52.51%compared with sterilized soil,respectively.The existence of soil microorganisms enhanced the allelopathy of the secondary metabolites of A.inebrians.A combination of microorganisms and aqueous extracts from the aboveground parts of A.inebrians had the strongest allelopathic effect on E.nutans.

Directional screening and identification of potential cytotoxic components from Achnatherum inebrians by a combination of surface palsmon resonance and chromatography

Objective:To establish a method for directional screening of the cytotoxic components from the medicinal herb of Achnatherum inebrians by a combination of surface plasmon resonance(SPR)biosensor and chromatographic isolation technology.Methods:Under the guidance of bioactive assessment based on binding abilities between objects and the a-Mannosidase(a-Man)target,the active components from different solvents extracts,different polar extraction parts and fractions were screened orderly and directionally using SPR.Components with a high binding ability to a-Man can be precisely oriented in a narrower fractions range and are easy to isolate.Three human cancer cells were used to evaluate the cytotoxic activity of component with the highest affinity to a-Man.Results:Eight compounds were isolated and identificated from A.inebrians for the first time.Deoxyvasicinone possessed the highest affinity to a-Man among them.Moreover,deoxyvasicinone showed good effects on inhibited proliferation of human hepatoma cells HepG2(IC_(50)=5.7 μmol/L),human breast cancer cells MCF7(IC_(50)=7.21 μmol/L)and human lung cancer cells HCC827(IC_(50)=0.75 μmol/L),respectively.In particular,its inhibitory effect on HCC827 was stronger than the positive drug gefitinib(IC_(50)=1.65 μmol/L).Conclusion:A comprehensive strategy of directional screening potential cytotoxic components from herb based on biomolecular interaction and chromatography was established.Deoxyvasicinone as an effective anti-cancer component was initially isolated from A.inebrians.It is expected that this screening strategy could provide new perspectives for rapid screening and identification of active components from natural plants with the complex matrix.

Effects of cutting frequency and height on alkaloid production in endophyte-infected drunken horse grass (Achnatherum inebrians)

An evaluation was performed on the influence of mowing height (2.5,5.0 or 7.5 cm) and mowing frequency (weekly or fortnightly) on levels of ergot alkaloids (ergine and ergonovine) formed in drunken horse grass,Achnatherum inebrians,grown under greenhouse conditions.Samples were taken monthly and alkaloids were extracted and analyzed by reverse-phase HPLC.Alkaloid levels increased more or less linearly with plant age over the first four months following establishment.Levels were higher in samples cut fortnightly compared to those cut weekly,and were higher when plants were cut at a mowing height of 7.5 cm vs.2.5 cm.In most cases,the highest alkaloid levels observed were almost three times those of the lowest.If plant protection applications are developed for the endophytic fungus,Neotyphodium gansuense,it will be necessary to be aware of the potential role of plant husbandry practices (e.g.,defoliation frequency and intensity) for reducing or enhancing levels of plant alkaloids.Similar husbandry factors may affect alkaloid levels in other Neotyphodium-grass associations,which would be interesting for further study.

The fungal endophyte Epichloëgansuensis increases NaCltolerance in Achnatherum inebrians through enhancing the activity of plasma membrane H^(+)-ATPase and glucose-6-phosphate dehydrogenase

Salt stress negatively affects plant growth,and the fungal endophyte Epichloëgansuensis increases the tolerance of its host grass species,Achnatherum inebrians,to abiotic stresses.In this work,we first evaluated the effects of E.gansuensis on glucose-6-phosphate dehydrogenase(G6PDH)and plasma membrane(PM)H^(+)-ATPase activity of Achnatherum inebrians plants under varying NaCl concentrations.Our results showed that the presence of E.gansuensis increased G6PDH,PMH^(+)-ATPase,superoxide dismutase and catalase activity to decrease O2•^(–),H_(2)O_(2)and Na^(+)contents in A.inebrians under NaCl stress,resulting in enhanced salt tolerance.In addition,the PM NADPH oxidase activity and NADPH/NADP+ratios were all lower in A.inebrians with E.ganusensis plants than A.inebrians plants without this endophyte under NaCl stress.In conclusion,E.gansuensis has a positive role in improving host grass yield under NaCl stress by enhancing the activity of G6PDH and PM H^(+)-ATPase to decrease ROS content.This provides a new way for the selection of stress-resistant and high-quality forage varieties by the use of systemic fungal endophytes.