Understanding the molecular basis of plant growth promotional effect of Pseudomonas fluorescens on rice through protein profiling

<p>Abstract</p> <p>Background</p> <p>Plant Growth Promoting Rhizobacteria (PGPR), <it>Pseudomonas fluorescens </it>strain KH-1 was found to exhibit plant growth promotional activity in rice under both <it>in-vitro </it>and <it>in-vivo </it>conditions. But the mechanism underlying such promotional activity of <it>P. fluorescens </it>is not yet understood clearly. In this study, efforts were made to elucidate the molecular responses of rice plants to <it>P. fluorescens </it>treatment through protein profiling. Two-dimensional polyacrylamide gel electrophoresis strategy was adopted to identify the PGPR responsive proteins and the differentially expressed proteins were analyzed by mass spectrometry.</p> <p>Results</p> <p>Priming of <it>P. fluorescens</it>, 23 different proteins found to be differentially expressed in rice leaf sheaths and MS analysis revealed the differential expression of some important proteins namely putative p23 co-chaperone, Thioredoxin h- rice, Ribulose-bisphosphate carboxylase large chain precursor, Nucleotide diPhosphate kinase, Proteosome sub unit protein and putative glutathione S-transferase protein.</p> <p>Conclusion</p> <p>Functional analyses of the differential proteins were reported to be directly or indirectly involved in growth promotion in plants. Thus, this study confirms the primary role of PGPR strain KH-1 in rice plant growth promotion.</p

GENE EXPRESSION DURING IMIDACLOPRID-INDUCED HORMESIS IN GREEN PEACH APHID

Imidacloprid-induced hormesis in the form of stimulated reproduction has previously been reported in green peach aphid, Myzus persicae. Changes in gene expression accompanying this hormetic response have not been previously investigated. In this study, expression of stress response (Hsp60), dispersal (OSD, TOL and ANT), and developmental (FPPS I) genes were examined for two generations during imidacloprid-induced reproductive stimulation in M. persicae. Global DNA methylation was also measured to test the hypothesis that changes in gene expression are heritable. At hormetic concentrations, down-regulation of Hsp60 was followed by up-regulation of this gene in the subsequent generation. Likewise, expression of dispersal-related genes and FPPS I varied with concentration, life stage, and generation. These results indicate that reproductive hormesis in M. persicae is accompanied by a complex transgenerational pattern of up- and down-regulation of genes that likely reflects trade-offs in gene expression and related physiological processes during the phenotypic dose-response. Moreover, DNA methylation in second generation M. persicae occurred at higher doses than in first-generation aphids, suggesting that heritable adaptability to low doses of the stressor might have occurred

Tasco®: A Product of Ascophyllum nodosum Enhances Immune Response of Caenorhabditis elegans Against Pseudomonas aeruginosa Infection

The effects of Tasco®, a product made from the brown seaweed (Ascophyllum nodosum) were tested for the ability to protect Caenorhabditis elegans against Pseudomonas aeruginosa infection. A water extract of Tasco® (TWE) reduced P. aeruginosa inflicted mortality in the nematode. The TWE, at a concentration of 300 µg/mL, offered the maximum protection and induced the expression of innate immune response genes viz.; zk6.7 (Lypases), lys-1 (Lysozyme), spp-1 (Saponin like protein), f28d1.3 (Thaumatin like protein), t20g5.7 (Matridin SK domain protein), abf-1 (Antibacterial protein) and f38a1.5 (Lectin family protein). Further, TWE treatment also affected a number of virulence components of the P. aeuroginosa and reduced its secreted virulence factors such as lipase, proteases and toxic metabolites; hydrogen cyanide and pyocyanin. Decreased virulence factors were associated with a significant reduction in expression of regulatory genes involved in quorum sensing, lasI, lasR, rhlI and rhlR. In conclusion, the TWE-treatment protected the C. elegans against P. aeruginosa infection by a combination of effects on the innate immunity of the worms and direct effects on the bacterial quorum sensing and virulence factors

Tasco®, a Product of Ascophyllum nodosum, Imparts Thermal Stress Tolerance in Caenorhabditis elegans

Tasco®, a commercial product manufactured from the brown alga Ascophyllum nodosum, has been shown to impart thermal stress tolerance in animals. We investigated the physiological, biochemical and molecular bases of this induced thermal stress tolerance using the invertebrate animal model, Caenorhabiditis elegans. Tasco® water extract (TWE) at 300 μg/mL significantly enhanced thermal stress tolerance as well as extended the life span of C. elegans. The mean survival rate of the model animals under thermal stress (35 °C) treated with 300 μg/mL and 600 μg/mL TWE, respectively, was 68% and 71% higher than the control animals. However, the TWE treatments did not affect the nematode body length, fertility or the cellular localization of daf-16. On the contrary, TWE under thermal stress significantly increased the pharyngeal pumping rate in treated animals compared to the control. Treatment with TWE also showed differential protein expression profiles over control following 2D gel-electrophoresis analysis. Furthermore, TWE significantly altered the expression of at least 40 proteins under thermal stress; among these proteins 34 were up-regulated while six were down-regulated. Mass spectroscopy analysis of the proteins altered by TWE treatment revealed that these proteins were related to heat stress tolerance, energy metabolism and a muscle structure related protein. Among them heat shock proteins, superoxide dismutase, glutathione peroxidase, aldehyde dehydrogenase, saposin-like proteins 20, myosin regulatory light chain 1, cytochrome c oxidase RAS-like, GTP-binding protein RHO A, OS were significantly up-regulated, while eukaryotic translation initiation factor 5A-1 OS, 60S ribosomal protein L18 OS, peroxiredoxin protein 2 were down regulated by TWE treatment. These results were further validated by gene expression and reporter gene expression analyses. Overall results indicate that the water soluble components of Tasco® imparted thermal stress tolerance in the C. elegans by altering stress related biochemical pathways

Tasco®, a Product of Ascophyllum nodosum, Imparts Thermal Stress Tolerance in Caenorhabditis elegans

Tasco®, a commercial product manufactured from the brown alga Ascophyllum nodosum, has been shown to impart thermal stress tolerance in animals. We investigated the physiological, biochemical and molecular bases of this induced thermal stress tolerance using the invertebrate animal model, Caenorhabiditis elegans. Tasco® water extract (TWE) at 300 µg/mL significantly enhanced thermal stress tolerance as well as extended the life span of C. elegans. The mean survival rate of the model animals under thermal stress (35 °C) treated with 300 µg/mL and 600 µg/mL TWE, respectively, was 68% and 71% higher than the control animals. However, the TWE treatments did not affect the nematode body length, fertility or the cellular localization of daf-16. On the contrary, TWE under thermal stress significantly increased the pharyngeal pumping rate in treated animals compared to the control. Treatment with TWE also showed differential protein expression profiles over control following 2D gel-electrophoresis analysis. Furthermore, TWE significantly altered the expression of at least 40 proteins under thermal stress; among these proteins 34 were up-regulated while six were down-regulated. Mass spectroscopy analysis of the proteins altered by TWE treatment revealed that these proteins were related to heat stress tolerance, energy metabolism and a muscle structure related protein. Among them heat shock proteins, superoxide dismutase, glutathione peroxidase, aldehyde dehydrogenase, saposin-like proteins 20, myosin regulatory light chain 1, cytochrome c oxidase RAS-like, GTP-binding protein RHO A, OS were significantly up-regulated, while eukaryotic translation initiation factor 5A-1 OS, 60S ribosomal protein L18 OS, peroxiredoxin protein 2 were down regulated by TWE treatment. These results were further validated by gene expression and reporter gene expression analyses. Overall results indicate that the water soluble components of Tasco® imparted thermal stress tolerance in the C. elegans by altering stress related biochemical pathways

Size Variability in Seed Lot Impact Seed Nutritional Balance, Seedling Vigor, Microbial Composition and Plant Performance of Common Corn Hybrids

Soils with highly uniform textural, physical, and chemical characteristics still give rise to crop stand variability. Seed quality is one of the factors adding to yield variability and has become a concern for corn growers. Hybrid seed producers claim that their seeds provide a uniformity in crop emergence and productivity, but they do not always provide detailed studies to support this claim. Based on growers&rsquo; concerns, we examined fields planted with three different hybrid varieties and found that 25% to 50% of the stand had relatively weak vigor, where seed variety A showed 15% of seedlings with lower vigor, and varieties B and C had 30% of seedlings with low vigor. These apparent differences in plant vigor prompted us to initiate a cursory investigation to identify how seed size influenced seedling vigor and if the seedling&rsquo;s microbial profile played a role in the early growth stages of three commonly grown corn hybrids in Ontario. Seeds were separated based on size, prior to conducting a growth room study. Different sizes of seeds from the same seed lot showed significant differences in vigor capacity and related biometric components. Significant differences were also found in their nutritional composition and microbial profiles within the different seed sizes and the roots and shoots of seedlings derived from such seeds. The results clearly indicate that seed size greatly impacts the plant growth and its microbiome, resulting in seedlings with different plant vigor, microbiomes, and performance

Sugarcane growth and nutrition levels are differentially affected by the application of PGPR and cane waste

Mineral and organic fertilization can be optimized by using rhizobacteria which increases dry matter, yield, and nutrients in the soil and plant, among the other biological inputs. However, the discovery of single microbes or a consortium that can benefit plants has been a challenge. In this context, this study aimed to evaluate the effects of Bacillus subtilis and Bacillus pumilus combined with mineral fertilization and sugar and alcohol industry by-products in presprouted and the initial growth phase of sugar cane seedlings. The study was carried out in two phases. Phase 1 included presprouted seedlings with T1 = untreated control, T2 = B. subtilis, T3 = B. pumilus, and T4 = B. subtilis + B. pumilus treatments. Phase 2 included the same treatments with four types of fertilization: F1 = mineral fertilization, F2 = mineral fertilization + vinasse, F3 = mineral fertilization + filter cake, and F4 = mineral fertilization + filter cake compost. Of the phase 1 treatments, T2 (B. subtilis) was the best promoter of root growth and the total dry matter compared to the control with an increase of 23.0% compared to the control. In phase 2, B. pumilus application, increased the total dry matter by 13%, the number of tillers by 37%, and the diameter of the tillers by 48% when combined with mineral fertilization. The combined application of B. subtilis and B. pumilus increased the phosphorus content by 13% in soil treated with mineral fertilization and filter cake compost. The results of the this study strongly suggest that the use of B. subtilis and B. pumilus together with these by-products can improve soil fertility parameters and decrease adverse effects associated with vinasse fertilization, in addition to providing shoot and root growth and providing collective synergy for a high yield of sugarcane production with environmental benefits.Agricultural and Livestock Microbiology Post - Graduation Program School of Agricultural and Veterinarian Sciences São Paulo State University (UNESP) Jaboticabal BrazilA and L Biologicals Agroecological Research Services Centre London, ON Canad