Tag: microorganisms
PCR Based Detection Of Entomopathogenic Fungus Metarhizium Anisopliae In Host Organisms
PCR based detection and identification of the entomopathogenic fungus Metarhizium anisopliae was conducted with specific primers F3 (5’-GGGTATATGAGAGGGAGGGC-3’) and B3 (5’- GGTTCCTGGTCGGGACTT-3’) which amplify a fragment of gene in the IGS (Intergenic spacer) region of rRNA (Ribosomal RNA) of M. anisopliae. The PCR amplification of IGS sequences yielded a unique fragment of 226-bp for all the four strains of M. anisopliae (M4, M16, M34 and M43). The results proved that the primers F3 and B3 were highly specific for M. anisopliae. PCR based detection M. anisopliae within host insects as Mealworm beetle (Tenebrio molitor) in the laboratory and cockchafer (Melolontha spp) in the field by using specific primers was applied. The PCR method could be a simple, rapid method to detect M. anisopliae within host insects just 8 days after infection. This study also showed that M. anisopliae exists in the soils in Felsrs-Köveskútpuszta region in Hungary. In fact, the results proved that DNA extracted from infected insects in laboratory and field could be used to identify the presence of the entomopathogen fungus M. anisopliae by using specific primers. Our study demonstrates an alternative approach for typing M. anisopliae strains within infected insects and reduces the need for time-consuming morphological and physiological tests.
Continental-scale insights into the soil microbial co-occurrence networks of Australia and their environmental drivers
Soil microbial communities and their interactions play a critical role in shaping the functions of ecosystems at regional and continental scales. In recent years, co-occurrence network analyses have provided a way to investigate microbial interactions among different microorganisms. But understanding how different environmental factors shape these networks at the continental scale remains challenging. Analyzing fungal, bacterial, and archaeal data from 166 study sites across Australia, we inferred a meta-community level soil microbial co-occurrence network for the Australian continent. Additionally, we analyzed node-level and network-level topological shifts associated with the five major vegetation types. Our results indicate that soils in the Australian savannah systems harbor a unique microbial association pattern, with the highest proportion of positive linkages, highest modularity and lowest average path length in comparison to soils from other vegetation types. Multi-model approaches revealed that different environmental drivers, including soil properties, temperature, and vegetation type, regulated the spatial distribution of topological parameters of the soil microbial networks analyzed in our study. We further generated high-resolution predication maps of microbial networks for Australia, providing insight into the distribution of soil microbes across the continent. By determining how the microbial co-occurrence networks vary according to vegetation type and mapping the distribution of the key parameters of these networks across Australia, we provide a unique understanding of microbial biogeography at the continental scale.
Towards a comprehensive understanding of free-living nitrogen fixation
Free-living nitrogen fixation (FNF) is a ubiquitous phenomenon that plays a modest role in the (N) economy of an ecosystem. However, sampling difficulties, methodological constraints and environmental controls have presented challenges for predicting the actual rate of FNF. Therefore, a deeper understanding of the accuracy to design models that consider dynamics, heterogeneity, influences, and other limitations is needed. This review presents an overview of the biology and diversity of microorganisms related to FNF as well as various ecological controls that influence these microorganisms. We also discussed contributions of FNF to the N input of various ecosystems. Overall, previous research has shown that considerable spatiotemporal variability exists in microbial types at both biome and microbiome scales, resulting in significant variation in FNF. Beyond this, rate of FNF is controlled by certain factors, such oxygen and metal ion availability, source of energy and soil nutrients, temperature, and pH. Empirical evidence increasingly indicates a significant contribution of FNF to N inputs in natural, agricultural, and aquatic ecosystems. It is inferred from this review that for the expanded exploitation of biological nitrogen fixation (BNF), we must pay additional attention to FNF because it occupies a central role within the process. Finally, we propose a framework for the quantification of FNF alongside a suite of recommendations that would deepen our understanding of FNF.
Unraveling consequences of soil micro- and nano-plastic pollution on soil-plant system: Implications for nitrogen (N) cycling and soil microbial activity
Micro- and nano-plastics have widely been recognized as major global environmental problem due to its widespread use and inadequate waste management. The emergence of these plastic pollutants in agroecosystem is a legitimate ecotoxicological concerns for food web exchanges. In agriculture, micro/nano plastics are originated from a variety of different agricultural management practices, such as the use of compost, sewage sludge and mulching. A range of soil properties and plant traits are affected by their presence. With the increase of plastic debris, these pollutant materials have now begun to demonstrate serious implications for key soil ecosystem functions, such as soil microbial activity and nutrient cycling. Nitrogen (N) cycle is key predictor of ecological stability and management in terrestrial ecosystem. In this review, we evaluate ecological risks associated with micro-nano plastic for soil-plant system. We also discuss the consequence of plastic pollutants, either positive or negative, on soil microbial activities. In addition, we systematically summarize both direct and hypothesized implications for N cycling in agroecosystem. We conclude that soil N transformation had showed varied effects resulting from different types and sizes of plastic polymers present in soil. While mixed effects of microplastic pollution on plant growth and yield have been observed, biodegradable plastics have appeared to pose greater risk for plant growth compared to chemical plastic polymers.