The microbial population dynamics in bulk and developing cucumber rhizospheres were studiedby cultivation and cultivation-independent approach based on directly extracted DNA toprovide baseline data. Soil and rhizosph...The microbial population dynamics in bulk and developing cucumber rhizospheres were studiedby cultivation and cultivation-independent approach based on directly extracted DNA toprovide baseline data. Soil and rhizosphere samples were taken from tested field 2, 4, 7 and10 weeks after the seeds were planted, which was positively related to the corresponding dateof cucumber growth stages. The plate culture amount showed that total number of bacteria,fungi and actinomyces began to rise when cucumber planted and quickly reached peak at seedlingor blossom period, but decreased slightly later. Bacterial population in rhizosphere washigher by comparison with that of counterpart except for seedling and flowering stages, butthe shift trend of them were quite similar all the time. Nitrogen fixating, nitrobacter andammonifying bacteria showed the same change tendency in population as bacteria and actinomycesdid, however, cellulose-decomposing bacteria had the contrary rhizosphere effect as cucumberdeveloped. Data revealed that positive relevance existed between the dominant rhizospheremicrobe population and cucumber development. PCR was employed to amplify the V3 region of 16SrDNA, then the products were subjected to denaturing gradient gel electrophoresis(DGGE). DGGEprofile indicated that a few microbe species lived stable in farmland soil, but some wereinfluenced by population due to cucumber roots growth. Significant difference was observed inbulk and rhizosphere soils especially for the seedling and flowering samples. Few prominentbands in DGGE patterns, which displayed stronger or less illumination, means the representativebacteria had great population variation in that period. These phenomena indicated thatflowering cucumber heavily affected rhizosphere bacteria, or the bacteria, most probably theuncultured bacteria, functioned specially to cucumber blossom. Most detected bands with noillumination change in DGGE quite possibly represent the indigenous microbes that wereessential for constructing and stabilizing farmland microecological environment.展开更多
Studying the relationship between rhizosphere microorganisms and root exudates is of great significance for the interaction between rhizosphere microorganisms and plants, and the prevention and control of soil-borne d...Studying the relationship between rhizosphere microorganisms and root exudates is of great significance for the interaction between rhizosphere microorganisms and plants, and the prevention and control of soil-borne diseases. This article analyzed the effects of different microorganisms on tobacco root exudates and rhizosphere microorganisms. It was found that the bacterial wilt pathogen can greatly increase acids and amines, while the probiotic <i>B. amyloliquefaciens</i> ZM9 can eliminate some acids and amines. The results of the study show that the root exudates of pathogenic bacteria may contain a variety of allelochemicals that cause soil-borne diseases.展开更多
Molecular biology covers a wide scope of problems related to molecular and cell biology including structural and functional genomics, transcriptomics, proteomics, bio- informatics, and biomedicines. Molecular biology ...Molecular biology covers a wide scope of problems related to molecular and cell biology including structural and functional genomics, transcriptomics, proteomics, bio- informatics, and biomedicines. Molecular biology is the study of molecular underpinnings of the processes of replication, transcription, translation, and cell function. The central dogma of molecular biology where genetic material is transcribed into RNA and then translated into proteins, despite being oversimplified, still provides a good starting point for understanding the field. The picture has been revised in light of emerging novel roles for RNA. Increasingly many other areas of biology focus on molecules, either directly or indirectly studying the interactions in their own right. The techniques and methods of molecular biology, such as molecular cloning, polymerase chain reaction, gel electrophoresis, macromolecule blotting and probing, microarray and so on, have been applied in biomedicine and herbal medicines.展开更多
文摘The microbial population dynamics in bulk and developing cucumber rhizospheres were studiedby cultivation and cultivation-independent approach based on directly extracted DNA toprovide baseline data. Soil and rhizosphere samples were taken from tested field 2, 4, 7 and10 weeks after the seeds were planted, which was positively related to the corresponding dateof cucumber growth stages. The plate culture amount showed that total number of bacteria,fungi and actinomyces began to rise when cucumber planted and quickly reached peak at seedlingor blossom period, but decreased slightly later. Bacterial population in rhizosphere washigher by comparison with that of counterpart except for seedling and flowering stages, butthe shift trend of them were quite similar all the time. Nitrogen fixating, nitrobacter andammonifying bacteria showed the same change tendency in population as bacteria and actinomycesdid, however, cellulose-decomposing bacteria had the contrary rhizosphere effect as cucumberdeveloped. Data revealed that positive relevance existed between the dominant rhizospheremicrobe population and cucumber development. PCR was employed to amplify the V3 region of 16SrDNA, then the products were subjected to denaturing gradient gel electrophoresis(DGGE). DGGEprofile indicated that a few microbe species lived stable in farmland soil, but some wereinfluenced by population due to cucumber roots growth. Significant difference was observed inbulk and rhizosphere soils especially for the seedling and flowering samples. Few prominentbands in DGGE patterns, which displayed stronger or less illumination, means the representativebacteria had great population variation in that period. These phenomena indicated thatflowering cucumber heavily affected rhizosphere bacteria, or the bacteria, most probably theuncultured bacteria, functioned specially to cucumber blossom. Most detected bands with noillumination change in DGGE quite possibly represent the indigenous microbes that wereessential for constructing and stabilizing farmland microecological environment.
文摘Studying the relationship between rhizosphere microorganisms and root exudates is of great significance for the interaction between rhizosphere microorganisms and plants, and the prevention and control of soil-borne diseases. This article analyzed the effects of different microorganisms on tobacco root exudates and rhizosphere microorganisms. It was found that the bacterial wilt pathogen can greatly increase acids and amines, while the probiotic <i>B. amyloliquefaciens</i> ZM9 can eliminate some acids and amines. The results of the study show that the root exudates of pathogenic bacteria may contain a variety of allelochemicals that cause soil-borne diseases.
文摘Molecular biology covers a wide scope of problems related to molecular and cell biology including structural and functional genomics, transcriptomics, proteomics, bio- informatics, and biomedicines. Molecular biology is the study of molecular underpinnings of the processes of replication, transcription, translation, and cell function. The central dogma of molecular biology where genetic material is transcribed into RNA and then translated into proteins, despite being oversimplified, still provides a good starting point for understanding the field. The picture has been revised in light of emerging novel roles for RNA. Increasingly many other areas of biology focus on molecules, either directly or indirectly studying the interactions in their own right. The techniques and methods of molecular biology, such as molecular cloning, polymerase chain reaction, gel electrophoresis, macromolecule blotting and probing, microarray and so on, have been applied in biomedicine and herbal medicines.
