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Aphid repellence in arabidopsis over-expressing FPS2Background and Aims: Plant-synthesized sesquiterpenes play a pivotal role in chemotactic interactions with insects. Biosynthesis of functionally diverse sesquiterpenes is dependent on the availability of a pool of the precursor farnesyldiphosphate (FDP). In Arabidopsis thaliana, FPS2, encoding cytosolic farnesyldiphosphate synthase, is implicated in the synthesis of cytosolic FDP, but it is not known whether enhanced levels of FDP have a commensurate effect on sesquiterpene-mediated defence responses. This study examined transgenic arabidopsis plants generated to over-express FPS2 in order to determine if any effects could be observed in the response of aphids, Myzus persicae. Methods Transgenic arabidopsis plants were generated to over-express FPS2 to produce FPS2 in either the cytosol or the chloroplasts. Morphochemical analyses of the transgenic plants were carried out to detremine growth responses of roots and shoots, and for GC-MS profiling of sesquiterpenes. Aphid response to hyrdo-distillate extracts and head-space volatiles from transgenic plants was assessed using a bioassay. Key Results Either over-expression of FPS2 in the cytosol or targetting of its translated product to chlorplasts resulted in stimulatory growth responses of transgenic arabidopsis at early and late developmental stages. GC-MS analysis of hydro-distillate extracts from aerial parts of the plants revealed biosynthesis of several novel sesquiterpenes, including E-β-farnesene, an alarm pheromone of aphids. Both entrapped volatiles and hydro-distillate extracts of the transgenic leaves triggered agitation in aphids, which was related to both time and dose of exposure. Conclusions Over-expression of FPS2 in the cytosol and targeting of its translated product to chloroplasts in arabidopsis led to synthesis of several novel sesquiterpenes, including E-β-farnesene, and induced alarm responses in M. persicae. The results suggest a potential for engineering aphid-resistant strains of arabidopsis.Not Availabl

Cold plasma processing: A review

The increase in the outbreaks reported due to consumption of infected produce has increased to a larger extent. Conventional technologies hamper the quality of food. To fulfill the need of an efficient cold processing method, researchers came up with a novel technology known as plasma technology. Two type's thermal and non-Thermal plasma exists. The non-Thermal or cold plasma technology is now the prime consideration in food processing industries viz. post-harvest, meat, packaging etc. Cold plasma plays an important role in decontamination of food and packaging materials from microorganisms, manufacturing of packaging materials, active packaging and retards browning reactions. Cold plasma withholds the ability to manufacture high quality fresh and processed food products

Improved Properties of Li-Mn-Ti Ferrites by Microwave Sintering

Substituted Li-ferrites are attractive materials for research due to their important properties like high Curie temperature leading to high thermal stability, high and wide range of saturation magnetization, low stress sensitivity of remanence and they are very good dielectric materials. The properties are very sensitive to the type and amount of substituents, method of preparation and sintering conditions. Attempts to minimize loss of lithia and oxygen during sintering by adopting various processing method, which otherwise is very difficult to control technologically by conventional method, has been a continuous efforts for the researchers.The present paper reports the improvements that arise in the properties of Li-Mn-Ti ferrite by using novel microwave (MW) processing technique. Mn4+ and Ti4+ substituted Li-ferrites having the compositional formula Li0.60Mn0.1Ti0.1Fe2.20O4 were prepared by both the conventional and microwave techniques. XRD confirmed the formation of single phase with spinel structures in both the samples. Dielectric properties were studied as a function of temperature. Dielectric properties of MW processed sample were found to be more stable with temperature. Significant improvement in the d. c. resistivity was observed in theMWsintered sample over the conventional sintered sample. The possiblemechanisms involved are discussed

Cold plasma processing: A review

The increase in the outbreaks reported due to consumption of infected produce has increased to a larger extent. Conventional technologies hamper the quality of food. To fulfill the need of an efficient cold processing method, researchers came up with a novel technology known as plasma technology. Two type's thermal and non-Thermal plasma exists. The non-Thermal or cold plasma technology is now the prime consideration in food processing industries viz. post-harvest, meat, packaging etc. Cold plasma plays an important role in decontamination of food and packaging materials from microorganisms, manufacturing of packaging materials, active packaging and retards browning reactions. Cold plasma withholds the ability to manufacture high quality fresh and processed food products

[In Press] Severe prolonged drought favours stress-tolerant microbes in Australian drylands

Drylands comprise one-third of Earth’s terrestrial surface area and support over two billion people. Most drylands are projected to experience altered rainfall regimes, including changes in total amounts and fewer but larger rainfall events interspersed by longer periods without rain. This transition will have ecosystem-wide impacts but the long-term effects on microbial communities remain poorly quantified. We assessed belowground effects of altered rainfall regimes (+65% and -65% relative to ambient) at six sites in arid and semi-arid Australia over a period of three years (2016–2019) coinciding with a significant natural drought event (2017–2019). Microbial communities differed significantly among semi-arid and arid sites and across years associated with variation in abiotic factors, such as pH and carbon content, along with rainfall. Rainfall treatments induced shifts in microbial community composition only at a subset of the sites (Milparinka and Quilpie). However, differential abundance analyses revealed that several taxa, including Acidobacteria, TM7, Gemmatimonadates and Chytridiomycota, were more abundant in the wettest year (2016) and that their relative abundance decreased in drier years. By contrast, the relative abundance of oligotrophic taxa such as Actinobacteria, Alpha-proteobacteria, Planctomycetes, and Ascomycota and Basidiomycota, increased during the prolonged drought. Interestingly, fungi were shown to be more sensitive to the prolonged drought and to rainfall treatment than bacteria with Basidiomycota mostly dominant in the reduced rainfall treatment. Moreover, correlation network analyses showed more positive associations among stress-tolerant dominant taxa following the drought (i.e., 2019 compared with 2016). Our result indicates that such stress-tolerant taxa play an important role in how whole communities respond to changes in aridity. Such knowledge provides a better understanding of microbial responses to predicted increases in rainfall variability and the impact on the functioning of semi-arid and arid ecosystems

Altered rainfall greatly affects enzyme activity but has limited effect on microbial biomass in Australian dryland soils

Drylands support a substantial proportion of the worlds biodiversity and are important to food production but are sensitive to changes in rainfall regimes. Altered rainfall has been shown to impact plant growth and soil microbial activity in drylands but the longer-term effect on belowground communities and biogeochemical cycles remains uncertain. We explored how four years of reduced and increased rainfall influenced soil total and available carbon (C), nitrogen (N) and phosphorus (P) content, microbial biomass and potential extracellular enzyme activity under field conditions at six dryland sites in eastern Australia. The study coincided with a severe 3-year drought that resulted in low standing plant biomass and soil C content at all sites. Microbial biomass attributes varied considerably across sites, with rainfall treatment effects limited to decreased fungal biomass and lower fungal:bacterial ratios in semi-arid Nyngan and reduced fungal:bacterial ratios and microbial biomass C in semi-arid Quilpie in reduced treatments compared with increased rainfall plots. Similarly, available soil C, N and P varied considerably among sites, with more available N and P at four and all sites, respectively, in reduced rainfall treatments particularly when compared with increased rainfall treatments. Rainfall treatments consistently influenced enzyme activity across all sites, with higher rates in increased rainfall plots indicative of greater microbial activity and enhanced nutrient cycling. Enzymatic activity associated with N cycling showed a negative relationship with available N while enzymes associated with P cycling related positively to available C and negatively to available P. This indicates that microbes invested more in production of enzymes associated with less available nutrients. Enzyme activity was not related to microbial biomass suggesting a disconnect between biomass and enzyme production and that rainfall treatments altered the ecosystem's specific enzyme activity (activity per unit of microbial biomass). Our results suggest that altered rainfall consistently impacted dryland ecosystem function, but that microbial biomass is a poor proxy for rainfall-induced changes in soil processes