diversity and activity of biosurfactant producing pseudomonas in the rhizosphere of Black Pepper in vietnam

Aims: Phytophthora capsici is a major pathogen of Black Pepper and zoospores play an important role in the infection process. Fluorescent pseudomonads that produce biosurfactants with zoosporicidal activities were isolated from the Black Pepper rhizosphere in Vietnam, and their genotypic diversity and potential to control Phy. capsici root rot was determined.

Methods:  Biosurfactant-producing pseudomonads were genotypically and biochemically characterized by BOX-polymerase chain reaction (PCR), 16S-rDNA sequencing, reverse-phase-high-performance liquid chromatography and liquid chromatography-masss spectrometry analyses.

Results:  Biosurfactant-producing fluorescent pseudomonads make up c. 1.3% of the culturable Pseudomonas population in the rhizosphere of Black Pepper. Although BOX-PCR revealed substantial genotypic diversity, the isolates were shown to produce the same biosurfactants and were all identified as Pseudomonas putida. When applied to Black Pepper stem cuttings, several of the biosurfactant-producing strains provided significant disease control. In absence of the disease, several of the bacterial strains promoted shoot and root growth of Black Pepper stem cuttings.

Conclusions:  Biosurfactant-producing pseudomonads indigenous to the rhizosphere of Black Pepper plants are genotypically diverse and provide a novel resource for the control of Phy. capsici root rot and growth promotion of Black Pepper stem cuttings.

Significance and Impact of the Study:  The results of this study provide a strong basis for further development of supplementary strategies with antagonistic bacteria to control foot and root rot of Black Pepper and to promote plant growth.

Diversity and activity of biosurfactant‐producing Pseudomonas in the rhizosphere of Black Pepper in Vietnam

Aims: Phytophthora capsici is a major pathogen of Black Pepper and zoospores play an important role in the infection process. Fluorescent pseudomonads that produce biosurfactants with zoosporicidal activities were isolated from the Black Pepper rhizosphere in Vietnam, and their genotypic diversity and potential to control Phy. capsici root rot was determined.

Methods:  Biosurfactant-producing pseudomonads were genotypically and biochemically characterized by BOX-polymerase chain reaction (PCR), 16S-rDNA sequencing, reverse-phase-high-performance liquid chromatography and liquid chromatography-masss spectrometry analyses.

Results:  Biosurfactant-producing fluorescent pseudomonads make up c. 1.3% of the culturable Pseudomonas population in the rhizosphere of Black Pepper. Although BOX-PCR revealed substantial genotypic diversity, the isolates were shown to produce the same biosurfactants and were all identified as Pseudomonas putida. When applied to Black Pepper stem cuttings, several of the biosurfactant-producing strains provided significant disease control. In absence of the disease, several of the bacterial strains promoted shoot and root growth of Black Pepper stem cuttings.

Conclusions:  Biosurfactant-producing pseudomonads indigenous to the rhizosphere of Black Pepper plants are genotypically diverse and provide a novel resource for the control of Phy. capsici root rot and growth promotion of Black Pepper stem cuttings.

Significance and Impact of the Study:  The results of this study provide a strong basis for further development of supplementary strategies with antagonistic bacteria to control foot and root rot of Black Pepper and to promote plant growth.

comparison of fungal community in Black Pepper vanilla and vanilla monoculture systems associated with vanilla fusarium wilt disease

Long-term vanilla monocropping often results in the occurrence of vanilla Fusarium wilt disease, seriously affecting its production all over the world. In the present study, vanilla exhibited significantly less Fusarium wilt disease in the soil of a long-term continuously cropped Black Pepper orchard. The entire fungal communities of bulk and rhizosphere soils between the Black Pepper-vanilla system (i.e., vanilla cropped in the soil of a continuously cropped Black Pepper orchard) and vanilla monoculture system were compared through the deep pyrosequencing. The results showed that the Black Pepper-vanilla system revealed a significantly higher fungal diversity than the vanilla monoculture system in both bulk and rhizosphere soils. The UniFrac-weighted PCoA analysis revealed significant differences in bulk soil fungal community structures between the two cropping systems, and fungal community structures were seriously affected by the vanilla root system. In summary, the Black Pepper-vanilla system harboured a lower abundance of F. oxysporum in the vanilla rhizosphere soil and increased the putatively plant-beneficial fungal groups such as Trichoderma and Penicillium genus, which could explain the healthy growth of vanilla in the soil of the long-term continuously cropped Black Pepper field. Thus, cropping vanilla in the soil of continuously cropped Black Pepper fields for maintaining the vanilla industry is executable and meaningful as an agro-ecological system.

diversity and activity of biosurfactant producing pseudomonas in the rhizosphere of Black Pepper in vietnam

Aims: Phytophthora capsici is a major pathogen of Black Pepper and zoospores play an important role in the infection process. Fluorescent pseudomonads that produce biosurfactants with zoosporicidal activities were isolated from the Black Pepper rhizosphere in Vietnam, and their genotypic diversity and potential to control Phy. capsici root rot was determined.

Methods:  Biosurfactant-producing pseudomonads were genotypically and biochemically characterized by BOX-polymerase chain reaction (PCR), 16S-rDNA sequencing, reverse-phase-high-performance liquid chromatography and liquid chromatography-masss spectrometry analyses.

Results:  Biosurfactant-producing fluorescent pseudomonads make up c. 1.3% of the culturable Pseudomonas population in the rhizosphere of Black Pepper. Although BOX-PCR revealed substantial genotypic diversity, the isolates were shown to produce the same biosurfactants and were all identified as Pseudomonas putida. When applied to Black Pepper stem cuttings, several of the biosurfactant-producing strains provided significant disease control. In absence of the disease, several of the bacterial strains promoted shoot and root growth of Black Pepper stem cuttings.

Conclusions:  Biosurfactant-producing pseudomonads indigenous to the rhizosphere of Black Pepper plants are genotypically diverse and provide a novel resource for the control of Phy. capsici root rot and growth promotion of Black Pepper stem cuttings.

Significance and Impact of the Study:  The results of this study provide a strong basis for further development of supplementary strategies with antagonistic bacteria to control foot and root rot of Black Pepper and to promote plant growth.

Diversity and activity of biosurfactant‐producing Pseudomonas in the rhizosphere of Black Pepper in Vietnam

Aims: Phytophthora capsici is a major pathogen of Black Pepper and zoospores play an important role in the infection process. Fluorescent pseudomonads that produce biosurfactants with zoosporicidal activities were isolated from the Black Pepper rhizosphere in Vietnam, and their genotypic diversity and potential to control Phy. capsici root rot was determined.

Methods:  Biosurfactant-producing pseudomonads were genotypically and biochemically characterized by BOX-polymerase chain reaction (PCR), 16S-rDNA sequencing, reverse-phase-high-performance liquid chromatography and liquid chromatography-masss spectrometry analyses.

Results:  Biosurfactant-producing fluorescent pseudomonads make up c. 1.3% of the culturable Pseudomonas population in the rhizosphere of Black Pepper. Although BOX-PCR revealed substantial genotypic diversity, the isolates were shown to produce the same biosurfactants and were all identified as Pseudomonas putida. When applied to Black Pepper stem cuttings, several of the biosurfactant-producing strains provided significant disease control. In absence of the disease, several of the bacterial strains promoted shoot and root growth of Black Pepper stem cuttings.

Conclusions:  Biosurfactant-producing pseudomonads indigenous to the rhizosphere of Black Pepper plants are genotypically diverse and provide a novel resource for the control of Phy. capsici root rot and growth promotion of Black Pepper stem cuttings.

Significance and Impact of the Study:  The results of this study provide a strong basis for further development of supplementary strategies with antagonistic bacteria to control foot and root rot of Black Pepper and to promote plant growth.