Isolation And Identification Of Endophytes From Special Rice Seeds And Their Function Research

Rice endophyte comprises fungus,bacterium and actinomycetes.They live with rice but do not harm rice apparently.Rice endophyte itself can produce some enzymes such as cellulase,and it can also improve the quality of rice such as resistance and nitrogen fixation ability.The endophyte of rice from different areas,different varieties and different parts have diversities.In this research,we isolated endophytic fungi and bacteria from special rice seeds of four varieties,and then analyzed the ITS or 16s rDNA of some endophyte from black rice.Then we screened the highest concerntration of cellulase produced by endophytic fungi strains and optimized the celllulase production condition.In this paper,we also studied the effect of 8 endophytic strains from black rice on the quality of blace rice and this research can be utilized to improve the quality of black rice.The main results are as follows:1.Isolation and identification of endophytic fungi from special rice seedsWe isolated 50 endophytic fungi strains from four varieties of special rice seeds totally.Then we analyzed 19 strains of them by ITS.The result was that the 19 strains were belong to 9 genus:Gibberella,Dothideomycete,Alternaria,Cochliobolus,Arthrinium,Phaeosphaeria,Colletotrichum,Fusarium,Phoma.2.Isolation and identification of endophytic bacteria from special rice seedsWe isolated 35 endophytic bacteria strains from four varieties of special rice seeds totally.Then we analyzed 9 strains of them by 16srDNA.The result was that the 9 strains were belong to 4 genus:Pantoea,Microbacterium,Xanthomonas and Curtobacterium.3.Screening fungi which can produced cellulase and optimizing the celllulase production condition.We screened out PT9-3 strain which had the highest cellulase activity from 50 endophytic fungi.And then we got the optimal condition of producing cellulase by PT9-3:straw content 1.88%,liquid medium volume 48mL,the initial pH 5.89,culture temperature 28?,inoculation quantity 5 slice/bottle,(NH4)2SO4 0.5%,shaking revolution 150rpm and the culture time was 5days.With the optimal condition,the cellulase activity is 5.57U/ml,which is 23.3%higher than that before optimizing.4.The effect of 8 endophyte strains on oxidation resistance of black rice8 endophyte strains sprayed to two black rice varieties in heading stage.The result of the experiment was that all 8 strains could remarkably improve the TOC of"1C902",the highest improvement was 6.30 fold and the quantity of improvement was 832.838Unit/g;6 strains of them could remarkably improve the SFRC of"1C902",the highest improvement was 130%and the quantity of improvement was 1855.348U/g;3 strains of them could remarkably improve the TOC of "1C903",the highest improvement was 1 10%and the quantity of improvement was 1855.348U/g;4 strains of them could remarkably improve the SFRC of "1C903",the highest improvement was 82.12%and the quantity of improvement was 848.19U/g.