| Datura metel L.is an annual herb belonging to the family Solanaceae,also known as "Hindu Datura".As an important medicinal plant,it has a wide range of pharmacological activities and great market demand.At present,it has become one of the eight medicinal plants with the largest production and circulation in the world.However,due to the serious destruction of the ecological environment and the excessive exploitation and utilization,there is a serious shortage of wild resources of Datura metel.Therefore,to construct the rapid artificial cultivation system of Datura metel and find its alternative resources is of great significance to solve the shortage of resources and to excavate and utilize its medicinal resources in an all-round way.A large number of studies have shown that medicinal plant endophytic fungi contain a variety of secondary metabolites which are the same or similar to their host plants in structure or activity.At the same time,it is also found that endophytic fungi can also promote the growth of host plants by producing iron carriers,secreting plant hormones,promoting plant absorption and other mechanisms.Therefore,on the one hand,medicinal plant endophytic fungi are an important resource bank for screening medicinal lead compounds,on the other hand,as plant growth promoters,they have potential application prospects in the construction of rapid and green artificial cultivation system of plants.Nevertheless,the studies on the biodiversity,active substances and growth-promoting characteristics of endophytic fungi of Datura metel have not been reported.Therefore,the biodiversity of endophytic fungi in roots,stems and leaves were systematically analyzed,and the anti-bacterial and skin pathogenic fungal activities were studied,in order to screen endophytic fungi with antibacterial activity,which will serve as a medicinal resource for Datura metel comprehensive development and utilization provide alternative resources.Meanwhile,the strains with growth-promoting characteristics were screened,which laid the foundation for the construction of the artificial rapid cultivation system of "endophytic fungi-Datura metel".The specific research contents and results are as follows:(1)The results of high-throughput sequencing of roots,stems and leaves in seedling stage,flowering stage and mature stage showed that in three growth cycles(seedling stage,flowering stage and mature stage),the diversity of endophytic fungi in leaves was significantly higher than that in roots and stems,and the diversity of endophytic fungi in roots,stems and leaves was the highest at maturity.The dominant groups in roots,stems and leaves at seedling stage were [ Fusarium(1.47%)and Cyathus(0.03%)]?[ Diaporthe(0.70%)and Colletotrichum(0.35%)]?[ Phyllosticta(0.09%)and Colletotrichum(0.02%)],At flowering stage,the dominant groups of root,stem and leaf were Subulicystidium(0.03%)?[ Asteromella(0.05%)and Ophiosphaerella(0.03%)] ? Malassezia(0.01%),The dominant groups in roots,stems and leaves at mature stage were [ Malassezia(0.04%)and Aspergillus(0.02%)] ? [ Aspergillus(0.04%)and Malassezia(0.04%)] ? [ Malassezia(0.05%)and Aspergillus(0.02%)].(2)292 strains of endophytic fungi were isolated from Datura metel L.by traditional isolation and culture methods,belonging to 34 genera.The dominant groups were Fusarium(72.97%)in roots,Fusarium(37.25%)and Plectosphaerella(28.43%)in stems,and Colletotrichum(39.66%)in leaves,respectively.The isolation rate(89.23%),colonization rate(84.62%)and diversity index(1.82)of endophytic fungi in leaves were the significantly higher than those in roots(70.48%,70.48% and 1.23)and stems(69.39%,68.03% and 1.64).(3)The antibacterial activity of 35 representative strains of Datura metel endophytic fungi were analyzed and the results showed that94% of endophytic fungi exhibited inhibitory activity against at least one of the tested bacteria strains,and the strains with Escherichia coli ?Shigella dysenteriae ? Bacillus subtilis ? Staphylococcus aureus ?Salmonella typhimurium accounted for 14.30%,20%,22.90%,22.90%,88.60%,respectively.Among them,the strain Periconia sp.S23 possessed all the five traits.The strains with inhibitory activity against Microsporum canis,Trichosporon mucoides,Trichophyton rubrum and Candida albicans accounted for 97.14%,71.43%,45.71%,and 25.71%,respectively.Among them,6 strains(17.14%)had inhibitory activities against all the four kinds of skin pathogenic fungi.They were Fusarium sp.R1,Penicillium sp.R5,Aspergillus sp.R7,Metarhizium sp.S18,Diaporthe sp.S19,and Glomerella sp.L57.(4)The results of growth-promoting properties of 35 representative strains showed that the proportions of the strains with nitrogen fixing,protease production,siderophore production,IAA production,dissolving phosphorus,dissecting phosphorus and dissolving potassium activity were 100%,71.43%,14.29%,88.57%,8.57%,14.29%and 17.14%,respectively.Among them,the strain Penicillium citrinum R5 possessed all the seven traits,showing the good plant growth-promoting potential,The ratio of the transparent circle of protease production,dissolving potassium,dissolving phosphorus,dissecting phosphorus ability to the diameter of the strain was 1.68,2.84,1.60,1.22,respectively.After re-screening,The phosphate ion concentration of dissolving phosphorus,dissecting phosphorus ability were 2.51 ?g / m L and 0.01 ?g / m L,respectively.The yield of IAA was 179.32 ?g / m L,and was finally identified as Penicillium citrinum by molecular identification.The species diversity of Datura metel L.endophytic fungi was very abundant,and its distribution has certain tissue and organ specificity.Among them,a relatively high proportion of endophytic fungi possessed the anti-skin fungal activities and growth-promoting properties,which could provide a resource pool for development of the new anti-dermatomycotic drugs and constructing the environmentally friendly cultivation system of "endophytic fungi-Datura metel". |
PDF Full Text Request