Effecting On Drought Resistance Of Dark Septate Endophytes In Blueberry Root

Blueberry is a plant of the genus Vaccinium Ericaceae.Because of its high nutritional value and health care value,it is deeply loved by consumers.Although the history of China's cultivation of blueberry has more than 30 years,because of the blueberry roots in the soil distribution is relatively shallow,no hair,so it is easily affected by the drought environment.Previous studies have shown that the inoculation of dark septate endophytic(DSE)can improve the drought resistance of plants.Therefore,we isolated the indigenous endophytic fungi from blueberry roots in the province,and then inoculation the fungi into the blueberry aseptic seedlings to screen the strain which can promote the growth and improve the drought resistance of Blueberry.1.Isolation of Endophytic Fungi from blueberry rootsWe collected the roots of blueberry as experimental materials from Blueberry base in Rushan.58 endophytic fungi were isolated from the roots of Blueberry.After the preliminary morphological observation,10 strains of fungi with obvious transverse septum were selected to analyze the effect of inoculation.2.Co-culture of DSE and blueberry aseptic seedlingsSelection of sterilized moss as co-culture medium,the above 10 kinds of endophytic fungi were inoculated into blueberry aseptic seedlings for symbiotic culture respectively.Symbiotic culture after 2 months,compared with non inoculated blueberry seedlings,inoculated blueberry seedlings is root abundance,deep green leaves,multiple tiller.The root of the blueberry seedling was taken to analyze the colonization of the strain in the root.The results showed that the R249 strains were colonized in the root of blueberry,and the structures of melanized septate hyphae and microsclerotia were formed in the cortical cells,but no R225 strain was found in the root of blueberry.3.Study on physiological stress of R249 fungi on Drought Resistance of blueberry seedlingsDifferent concentrations of PEG6000 solution were used for treatmenting inoculated and non inoculated blueberry seedlings.Then,the content of malondialdehyde,proline and chlorophyll content in blueberry leaves were determined.The results showed that inoculated R249 strains of blueberry leaf malondialdehyde content is lower,proline and chlorophyll content is higher.The results showed that the inoculation of R249 strain could improve the drought resistance of blueberry seedlings.4.Morphological and molecular identification of R225 and R249 strainsBased on the R225 and R249 colony and mycelium of morphology observation and rDNA-ITS sequence analysis,strain R225 was identified as Minutisphaera aspera;the R249 strain was identified as Dothideomycetes sp.Minutisphaera aspera and Dothideomycetes sp.are all belong to Ascomycota,Dothideomycetes.5.Effects of carbon and nitrogen sources on the growth of R225 and R249In this experiment,R225 and R249 fungi were cultured with different carbon sources and nitrogen sources on the basis of MMN solid medium.The results showed that R225 and R249 strains could grow in MMN solid medium containing different carbon and nitrogen sources.Among them,R249 with glucose and ammonium nitrate as the sole carbon and nitrogen source,the largest diameter of mycelium expansion,xylose and sodium nitrate as the sole carbon and nitrogen source,the maximum dry weight of mycelium;R225 with sodium bicarbonate and casein as the sole carbon and nitrogen source,the largest diameter of mycelium expansion,glucose and glycine as the sole carbon and nitrogen source,the maximum dry weight of mycelium.6.Myo-Inositol metabolism in blueberry fruitMyo-inositol(MI)metabolism in plant edible organs has become the focus of many recent studies because of its benefits to human health and its unique functions in normal plant development.In this study,MI contents were analyzed during the development of two blueberry cultivars,cv ‘Berkeley'and cv ‘Bluecrop'.Furthermore,two VcMIPS 1/2(Vaccinium corymbosum MIPS)genes,and one VcMIOX(Vaccinium corymbosum MIOX)gene were isolated for the first time from blueberry.The expression patterns of VcMIPS2 and VcMIOX genes showed a relationship with the change profiles of myo-inositol content during fruit ripening.Results indicated that both myo-inositol biosynthesis and oxidation played important roles in determining of myo-inositol levels during the development of blueberry.To our knowledge,this report is the first to discuss myo-inositol levels in fruits in terms of biosynthesis and catabolism.