Characterization of Plant Growth–Promoting Traits of Bacteria Isolated from Larval Guts of Diamondback Moth Plutella xylostella (Lepidoptera: Plutellidae)
ABSTRACT Eight bacterial isolates from the larval guts of Diamondback moths (Plutella xylostella) were tested for their plant growth-promoting (PGP) traits and effects on early plant growth. All of the strains tested positive for nitrogen fixation and indole 3-acetic acid (IAA) and salicylic acid production but negative for hydrogen cyanide and pectinase production. In addition, five of the isolates exhibited significant levels of tricalcium phosphate and zinc oxide solubilization; six isolates were able to oxidize sulfur in growth media; and four isolates tested positive for chitinase and beta-1,3-glucanase activities. Based on their IAA production, six strains including four that were 1-aminocyclopropane-1-carboxylate (ACC) deaminase positive and two that were ACC deaminase negative were tested for PGP activity on the early growth of canola and tomato seeds under gnotobiotic conditions. Acinetobacter sp. PSGB04 significantly increased root length (41%), seedling vigor, and dry biomass (30%) of the canola test plants, whereas Pseudomonas sp. PRGB06 inhibited the mycelial growth of Botrytis cinerea, Colletotrichum coccodes, C. gleospoiroides, Rhizoctonia solani, and Sclerotia sclerotiorum under in vitro conditions. A significant increase, greater than that of the control, was also noted for growth parameters of the tomato test plants when the seeds were treated with PRGB06. Therefore, the results of the present study suggest that bacteria associated with insect larval guts possess PGP traits and positively influence plant growth. Therefore, insect gut bacteria as effective PGP agents represent an unexplored niche and may broaden the spectrum of beneficial bacteria available for crop production.
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- "ACC deaminase, IAA, siderophore Poonguzhali et al. (2008) Serratia marcescens IAA, siderophore, HCN Selvakumar et al. (2008) Pseudomonas fluorescens ACC deaminase, phosphate solubilization Shaharoona et al. (2008) Acinetobacter sp., Pseudomonas sp. ACC deaminase, IAA, antifungal activity, N 2 -fixation, phosphate solubilization Indiragandhi et al. (2008) Enterobacter sp. ACC deaminase, IAA, siderophore, phosphate solubilization Kumar et al. (2008) Burkholderia ACC deaminase, IAA, siderophore, heavy metal solubilization, phosphate solubilization Jiang et al. (2008) Pseudomonas jessenii ACC deaminase, IAA, siderophore, heavy metal solubilization, phosphate solubilization Rajkumar and Freitas (2008) Pseudomonas aeruginosa ACC deaminase, IAA, siderophore, phosphate solubilization Ganesan (2008) ACC: 1-aminocyclopropane-1-carboxylate; EPS: exopolysaccharides; IAA: indole acetic acid. "
ABSTRACT: Various industrial, agricultural and military operations have released huge amounts of toxic heavy metals into the environment with deleterious effects on soils, water and air. Under metal stress, soil microorganisms including plant growth promoting bacteria (PGPB) have developed many strategies to evade the toxicity generated by the various heavy metals. Such metal resistant PGPB, when used as bioinoculant or biofertilizers, significantly improved the growth of plants in heavy metal contaminated/ stressed soils. Application of bacteria possessing metal detoxifying traits along with plant-beneficial properties is a cost effective and environmental friendly metal bioremediation approach. This review highlights the different mechanisms of metal resistance and plant growth promotion of metal resistant PGPB as well as the recent development in exploitation of these bacteria in bioremediation of heavy metals in different agroecosystems.Arabian Journal of Chemistry 11/2014; 158. DOI:10.1016/j.arabjc.2014.11.020 · 2.68 Impact Factor
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- "Con respecto a los miembros del género Acinetobacter identicados en el estudio, es importante indicar que dichas bacterias se caracterizan por ser saprófitas habitantes de suelos, cuerpos de agua, aguas residuales, alimentos y por no ser fermentativas . Diferentes estudios han indicado que esta bacteria es también una importante PGPR y, por tanto, podría ser formulada como biofertilizante de amplio espectro por su capacidad probada para solubilizar fosfatos, fijar N2 y producir ácido indolacético (AIA) (Indiragandhi et al., 2008; Gulati et al., 2009). Adicionalmente, se ha encontrado que bacterias del género Acinetobacter, además de Pseudomonas, Bacillus, Rhodococcus, Rhizobium y Mycobacterium tienen capacidad de producir AIA (Tsavkelova et al., 2007). "
ABSTRACT: The cultivation of vanilla (Vanilla planifolia) is highly promising in Colombia, but more research is needed on its agronomical management and beneficial microorganisms that grow associated to its rhizosphere, on which the plant depends for its nutrition and growth. This study involved the identification of microorganisms associated to the rhizosphere of vanilla plants in a crop located in Sopetrán, Colombia. The microbes were isolated in selective media for functional groups such as cellulolytic, proteolytic, inorganic and organic phosphate (phytate) solubilizers, and asymbiotic nitrogen fixing bacteria. After isolation and purification, 109 microbial isolates were obtained. DNA was extracted from 52 selected isolates for molecular identification based on ITS and 16S rDNA sequencing, for fungi and bacteria, respectively. The diversity of rhizosphere microorganisms found was significant. Bacteria such as Bacillus megaterium, Pseudomonas koreensis and Acinetobacter sp., and the fungus Plectosphaerella sp., may have a high potential to be used as biofertilizers to improve vanilla plant nutrition and growth.Acta Biologica Colombiana 01/2013; 18(2):293-306.
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- "ACC deaminase, IAA, siderophore Poonguzhali et al. (2008) Serratia marcescens IAA, siderophore, HCN Selvakumar et al. (2008) Pseudomonas fluorescens ACC deaminase, phosphate solubilization Shaharoona et al. (2008) Acinetobacter sp., Pseudomonas sp. ACC deaminase, IAA, antifungal activity, N 2 -fixation, phosphate solubilization Indiragandhi et al. (2008) Enterobacter sp. ACC deaminase, IAA, siderophore, phosphate solubilization Kumar et al. (2008) Burkholderia ACC deaminase, IAA, siderophore, heavy metal solubilization, phosphate solubilization Jiang et al. (2008) Pseudomonas jessenii ACC deaminase, IAA, siderophore, heavy metal solubilization, phosphate solubilization Rajkumar and Freitas (2008) Pseudomonas aeruginosa ACC deaminase, IAA, siderophore, phosphate solubilization Ganesan (2008) Pseudomonas sp. "
ABSTRACT: Plant growth promoting rhizobacteria are the soil bacteria inhabiting around/on the root surface and are directly or indirectly involved in promoting plant growth and development via production and secretion of various regulatory chemicals in the vicinity of rhizosphere. Generally, plant growth promoting rhizobacteria facilitate the plant growth directly by either assisting in resource acquisition (nitrogen, phosphorus and essential minerals) or modulating plant hormone levels, or indirectly by decreasing the inhibitory effects of various pathogens on plant growth and development in the forms of biocontrol agents. Various studies have documented the increased health and productivity of different plant species by the application of plant growth promoting rhizobacteria under both normal and stressed conditions. The plant-beneficial rhizobacteria may decrease the global dependence on hazardous agricultural chemicals which destabilize the agro-ecosystems. This review accentuates the perception of the rhizosphere and plant growth promoting rhizobacteria under the current perspectives. Further, explicit outlooks on the different mechanisms of rhizobacteria mediated plant growth promotion have been described in detail with the recent development and research. Finally, the latest paradigms of applicability of these beneficial rhizobacteria in different agro-ecosystems have been presented comprehensively under both normal and stress conditions to highlight the recent trends with the aim to develop future insights.Journal of King Saud University - Science 01/2013; 26(1). DOI:10.1016/j.jksus.2013.05.001