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B. R. Pati

Bio: B. R. Pati is an academic researcher from University of Calcutta. The author has contributed to research in topics: Pesticide & Nitrogen fixation. The author has an hindex of 2, co-authored 2 publications receiving 33 citations.

Papers
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Journal ArticleDOI
TL;DR: Culture of two nitrogen-fixing bacteria isolated from rice and jute phyllospheres respectively were sprayed on wheat plants as substitute for nitrogenous fertilisers and there was a marked improvement in yield and growth of the plants.
Abstract: Culture of two nitrogen-fixing bacteria (REN2 and JN1) isolated from rice and jute phyllospheres respectively, were sprayed on wheat plants as substitute for nitrogenous fertilisers. There was a marked improvement in yield and growth of the plants. An average increase in yield by 70% was obtained which was very near to that obtained by fertilizer treatment.

32 citations

Journal ArticleDOI
TL;DR: Thein vitro effects of twelve commonly used pesticides, including the fungicides Cuman-L (Ziram) and Hinosan (Ediphenphos), the acaricides Nuvacron (Monocrotophos), Ekatin 25EC (Thiometon) and Ekalux-G5 (Quinalphos) and other insecticides on the nitrogen fixing bacteria isolated from the phyllosphere of some crop plants were tested.
Abstract: Thein vitro effects of twelve commonly used pesticides, including the fungicides Cuman-L (Ziram) and Hinosan (Ediphenphos), the acaricides Nuvacron (Monocrotophos), Ekatin 25EC (Thiometon) and Ekalux-G5 (Quinalphos) and other insecticides namely Dimecron (Phosphamidon), Anthio 25EC (Formothion), Baytex (Fenthion), Metasystox (Methyl demeton) and Phosalone (Zolone), on the nitrogen fixing bacteria isolated from the phyllosphere of some crop plants were tested. A very wide variation of the effect of these pesticides on the different organisms was noted. At a concentration of 700 μg/ml in the medium, most of the pesticides completely inhibited growth of the nitrogen fixing bacterial isolates. However, with some pesticides, when used at a lower concentration, a degree of growth stimulation was recorded.

5 citations


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Journal ArticleDOI

2,133 citations

Journal ArticleDOI
TL;DR: This review focuses on the bacterial component of leaf microbial communities, with emphasis on P. syringae—a species that participates in leaf ecosystems as a pathogen, ice nucleus, and epiphyte, to illustrate the attractiveness and somewhat unique opportunities provided by leaf ecosystems for addressing fundamental questions of microbial population dynamics and mechanisms of plant-bacterium interactions.
Abstract: The extremely large number of leaves produced by terrestrial and aquatic plants provide habitats for colonization by a diversity of microorganisms. This review focuses on the bacterial component of leaf microbial communities, with emphasis on Pseudomonas syringae—a species that participates in leaf ecosystems as a pathogen, ice nucleus, and epiphyte. Among the diversity of bacteria that colonize leaves, none has received wider attention than P. syringae, as it gained notoriety for being the first recombinant organism (Ice− P. syringae) to be deliberately introduced into the environment. We focus on P. syringae to illustrate the attractiveness and somewhat unique opportunities provided by leaf ecosystems for addressing fundamental questions of microbial population dynamics and mechanisms of plant-bacterium interactions. Leaf ecosystems are dynamic and ephemeral. The physical environment surrounding phyllosphere microbes changes continuously with daily cycles in temperature, radiation, relative humidity, wind velocity, and leaf wetness. Slightly longer-term changes occur as weather systems pass. Seasonal climatic changes impose still a longer cycle. The physical and physiological characteristics of leaves change as they expand, mature, and senesce and as host phenology changes. Many of these factors influence the development of populations of P. syringae upon populations of leaves. P. syringae was first studied for its ability to cause disease on plants. However, disease causation is but one aspect of its life strategy. The bacterium can be found in association with healthy leaves, growing and surviving for many generations on the surfaces of leaves as an epiphyte. A number of genes and traits have been identified that contribute to the fitness of P. syringae in the phyllosphere. While still in their infancy, such research efforts demonstrate that the P. syringae-leaf ecosystem is a particularly attractive system with which to bridge the gap between what is known about the molecular biology of genes linked to pathogenicity and the ecology and epidemiology of associated diseases as they occur in natural settings, the field.

877 citations

Book ChapterDOI
TL;DR: The major function of the polyester in plants is as a protective barrier against physical, chemical, and biological factors in the environment, including pathogens.
Abstract: Polyesters occur in higher plants as the structural component of the cuticle that covers the aerial parts of plants. This insoluble polymer, called cutin, attached to the epidermal cell walls is composed of interesterified hydroxy and hydroxy epoxy fatty acids. The most common chief monomers are 10, 16-dihydroxy C16 acid, 18-hydroxy-9, 10 epoxy C18 acid, and 9, 10, 18-trihydroxy C18 acid. These monomers are produced in the epidermal cells by ω hydroxylation, in-chain hydroxylation, epoxidation catalyzed by P450-type mixed function oxidase, and epoxide hydration. The monomer acyl groups are transferred to hydroxyl groups in the growing polymer at the extracellular location. The other type of polyester found in the plants is suberin, a polymeric material deposited in the cell walls of a layer or two of cells when a plant needs to erect a barrier as a result of physical or biological stress from the environment, or during development. Suberin is composed of aromatic domains derived from cinnamic acid, and aliphatic polyester domains derived from C16 and C18 cellular fatty acids and their elongation products. The polyesters can be hydrolyzed by pancreatic lipase and cutinase, a polyesterase produced by bacteria and fungi. Catalysis by cutinase involves the active serine catalytic triad. The major function of the polyester in plants is as a protective barrier against physical, chemical, and biological factors in the environment, including pathogens. Transcriptional regulation of cutinase gene in fungal pathogens is being elucidated at a molecular level. The polyesters present in agricultural waste may be used to produce high value polymers, and genetic engineering might be used to produce large quantities of such polymers in plants.

403 citations

Journal ArticleDOI
TL;DR: Three nitrogen fixing bacteria, particularly the Azotobacter, as a foliar biofertilizer to increase mulberry leaf production resulted in improved leaf quality as indicated by their protein content and their impact on silkworm rearing and cocoon production when treated leaves were subjected to bioassay.
Abstract: A field experiment was conducted for two years (1994-96) to evaluate three nitrogen fixing bacteria (NFBs) namely Azotobacter, Azospirillum and Beijerinckia as foliar biofertilizers on mulberry (Morus spp.). Foliar application of these bacteria in their specific culture media with half of the recommended dose of N as a basal application of chemical fertilizer were compared with the recommended dose of N (300 kg/ha per year in four equal splits) but without biofertilizer. Other controls for comparison were respective culture media with half N. All the NFBs improved leaf yield over their respective controls (specific culture media). The addition of Azotobacter resulted in significantly greater yield than that given by the recommended dose of N. The Beijerinckia treatment resulted in a leaf yield equal to that from the recommended dose of N and Azospirillum reduced leaf yield in comparison to that from the recommended N treatment although the yield from Azospirillum treatment was more than that from the culture medium treatments. A combination of NFBs where Azotobacter was one of the components improved leaf yield over single NFB treatments. NFBs also resulted in improved leaf quality as indicated by their protein content and their impact on silkworm rearing and cocoon production when treated leaves were subjected to bioassay. The use of these NFBs, particularly the Azotobacter, as a foliar biofertilizer to increase mulberry leaf production has not been investigated before.

138 citations

Journal ArticleDOI
TL;DR: A phyllospheric bacterial culture found to contain a fluorescent pseudomonas which was identified as Pseudomonas putida and a Corynebacterium sp.
Abstract: A phyllospheric bacterial culture, previously reported to partially replace nitrogen fertilizer (B. R. Patti and A. K. Chandra, Plant Soil 61:419-427, 1981) was found to contain a fluorescent pseudomonas which was identified as Pseudomonas putida and a Corynebacterium sp. The P. putida isolate was found to produce an extracellular cutinase when grown in a medium containing cutin, the polyester structural component of plant cuticle. The Corynebacterium sp. grew on nitrogen-free medium but could not produce cutinase under any induction conditions tested, whereas P. putida could not grow on nitrogen-free medium. When cocultured with the nitrogen-fixing Corynebacterium sp., the P. putida isolate grew in a nitrogen-free medium, suggesting that the former provided fixed N2 for the latter. These results suggest that the two species coexist on the plant surface, with one providing carbon and the other providing reduced nitrogen for their growth. The presence of cutin in the medium induced cutinase production by P. putida. However, unlike the previously studied fungal systems, cutin hydrolysate did not induce cutinase. Thin-layer chromatographic analysis of the products released from labeled apple fruit cutin showed that the extracellular enzyme released all classes of cutin monomers. This enzyme also catalyzed hydrolysis of the model ester substrates, p-nitrophenyl esters of fatty acids, and optimal conditions were determined for a spectrophotometric assay with p-nitrophenyl butyrate as the substrate. It did not hydrolyze triacyl glycerols, indicating that the cutinase activity was not due to a nonspecific lipase. It showed a broad pH optimum between 8.0 and 10.5 with 3H-labeled apple cutin as the substrate.(ABSTRACT TRUNCATED AT 250 WORDS)

59 citations