| Fifty endophytic bacillus strains isolated from medicinal plants were characterized by numerical taxonomy,16S rDNA PCR-RFLP,BOX-PCR fingerprints and 16S rDNA sequence to describe the biological diversity and phylogeny.The antagonism of the isolates against pathogenic fungi from crops were tested at same time.The main results were as follows:A high phenotypic and phylogenetic diversity of endophytic bacillus isolated from Medicinal plants.And compared with standarded strains,according to cluster analysis of phenotypic character,16S rDNA PCR-RFLP and BOX-PCR,the isolates were divided into 13 phenons,16 and 27 gentic groups respectively.The phenotypic characterization of these strains showed that most of these strains had high stress resistance.Among the restriction enzymes used,Mspl was the most discriminating enzyme.The genetic diversity was high revealed by BOX-PCR.BOX-PCR fingerprinting is appropriate as a method revealing genetypic diversity within a bacillus species and strains.Strains belonged to one pheno in numerical taxonomy always distributed into several BOX-PCR groups.Overall,the analysis of phenotypic and genotypic diversity was good agreement with each other,which approved the research results were credible and stable.Based on the result,the 16S rRNA gene of representative strains were completely sequenced,and the phylogenetic tree was reconstructed.The results showed that SCAU11 was highly related to B sphaericus,SCAU78 and SCAU25 were identified as B subtilis subspecies,SCAU39 was highly related to B megaterium.The phylogenic relationship constructed by the 16S rDNA gene full sequence.The result of antagonistic test supported that SCAU11,SCAU10,SCAU49, SCAU33 and SCAU46 in the strains tested displayed a stronger antagonistic effect against pathogenic microorganism(Curvularia Lunata,Fusarium graminear,Fusarium moniliforme,Setosphaeria Turcica and Sclerotinia sclerotiorum) than the others.This study laid a foundation for applying of bacillus in biological control.
|
PDF Full Text Request