Biodiversity Of Endophytic Fungi From Adlay(Coix Lacrymajobi L.var. Mayuen.) And Their Correlations With The Crud Drug Quality Of The Host Plants

In this paper, we conducted a systematic study of the endophytic fungi and the medicinalherb adlay (Coix lacrymajobi L. var. mayuen.), with a particular emphasis on the factorsthat possibly influence the population structure of endophytic fungi and benefits to the hostplant from the existence of endophytic fungi. We hope that the research will provide usefulinformation for a wide range of audience to understand the relationships betweenendophytic fungi and host medicinal plants, which can help us to design strategies for theefficient production of the bioactive metabolites through selecting proper medicinal hostplants occurring in the suitable environment. Ideally, a system mimicking the mutualisticor antagonistic symbiosis conditions of endophytic fungi and the host plants may beestablished to effectively produce the desired drug compounds through bioengineering, ifthe relationships and conditions that promote the production of the compounds are clearlyunderstood.More than3266endophytic fungal strains were isolated from tissues (leaf, stem andseed) of adlay at eight locations in China. The strains were distributed among eightprovinces, including Hainan (262), Liaoning (466), Anhui (370), Zhejiang (467), Sichuan(403), Fujian (365), Yunnan (466) and Shangha (467), respectively. These strains belongedto88taxa based on morphology and molecular (ITS1and ITS2regions and the intervening5.8S rDNA region) analyses. Of these85taxa (96.6%) can be classified as Ascomycota,3(3.4%) to Basidiomycot.The analytical results indicated that the distribution and population structure ofendophytes from adlay can be considerably affected by factors, such as the environmentalconditions and tissues of host plants. The distribution pattern of the dominant fungi and thecommon fungi at taxonomic levels (order, genus and specie) were significantly affected bylocalities and tissues. The dominant orders at eight locations were Hypocreales,Pleosporales and Glomerellales. Gibberella/Fusarium, Edenia, Colletotrichum,Phaeosphaeria/Glomerella, Xylaria, Cochliobolu, Trichoderma were the dominant generaat eight locations. Among the15dominant fungi, Gibberella moniliformis was the mostdominant speice in every place. Only four taxa shared among the eight localities,they wereEdenia gomezpompae, Fusarium sp.2, Fusarium sp.4å'ŒGibberella moniliformis,separately. The colonization of endophytic fungi was significantly determined by differentplant tissues producing differential substrates. The species richness and diversity of endophytic fungi in the leaves was1.57fold higher comparing to the tissues of stems andseeds. These results indicate the richness of endophytic fungi residing in adlay plants,which provides opportunities to study fungal-host relationships and to explore new geneticresources for bioactive compounds.We also found that there was a correlation between the population structure ofendophytic fungi and chemical constituents of host plant-adlay. The results suggested thatthe contents of two active ingredients （Triolein and Coixol）in adlay were related to thediversity and species of endophytic fungi. The most dominant fungi AH13Gibberellamoniliformis showed a significant correlation with the ingredient ofTriolein. Anotheractive ingredient-Coixol in the adlay leaves was related with the dominant fungi LN7E.gomezpompae.The fungus produced Triolein (trioleoylglycerol), a major constituent oftriacylglycerols (TAGs) of adlay, in rich PDB medium under shake flask and bench scalefermentation conditions. The fungus was identified as Gibberella moniliformis (Fusariumverticillioides) by its morphology and authenticated by ITS analysis (ITS1and ITS2regions and the intervening5.8S rDNA region). Triolein was identified by HPLC-ELSDcoupled with APCI-MS and confirmed through comparison with authentic standard.Moreover, the EtOAc extract of AH13G. moniliformis showed strong antitumour activityagainst four types of tumour cells (A549, HCT116, MDA-MB-231, and SW1990). Theseresults suggest that AH13G. moniliformis in adlay has significant scientific and industrialpotential to meet the pharmaceutical demands and sustainable energy requirements forTAGs in a cost-effective, easily accessible and reproducible way, and is also a potentialnovel source of natural antitumour bioactive agents. The concentration of Trioleinproduced by AH13G. moniliformis reached2.536±0.006mg/g dry weight of myceliumin rich rice medium.Furthermore，our research further indicated the benefits conferred by someendophytic fungi to the host plant after colonization. Results indicated that the endophyticfungus ZJ44Epichlo sp. was able to increase the growth of the host plant-adlay byactivating the expression of a certain enzym which could enhance the resistance of hostplants to biotic and abiotic stresses. The activities of SOD，POD, MDA and PAL in theleaves of adlay inoculated the fungus ZJ44were1.65,1.72,0.82,1.25fold comparing tothe plants which not inoculated endophytic fungi. Results also showed that ZJ44E. sp. hadthe ability to promote the accumulation of secondary metabolites of host plant-adlay, which influenced the quantity and quality of drugs. The Coixol contents in the roots, stemsand leaves of adlay which innoculated the endophytic fungi ZJ44were1.49,1.63and1.39fold higher comparing to the tissues of adlay which uninnoculated endophytic fungi.We investigated the role of endophytic fungus ZJ44E. sp. in regulating the growthand development of Arobidopis (Arabdopsis thaliana) seedings by developingplant-fungus interaction systems. Wild-type Arabidopsis seedlings inoculated with ZJ44E.sp. showed characteristics, including increased biomass production and stimulated lateralroot development. Results from our reseach clearly indicated that E. sp.increased thegrowth of Arobidopis by stimulating the development of lateral roots, modulating rootsystem architecture and obtaining nutritional elements useful for plants.