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Use of plant growth-promoting rhizobacteria isolates as a potential biofertiliser for wheat
Plant growth-promoting rhizobacteria (PGPR) isolated from the rhizosphere soil of eight field crops at different locations in Egypt were identified. Rhizobacteria strains were identified as Bacillus endophyticus AW1 5, B. filamentosus EM9, ET3, Micrococcus luteus KT2, FW9, FC13, SaW4, Enterobacter cloacae SK18, Pseudomonas azotoformans TPo10, Citrobacter braakii TC3. All isolates solubilised insoluble phosphate and produced IAA, while only six were able to produce siderophores in vitro. Vegetative growth and yield of wheat cv. ‘Sakha 94’ were enhanced after the application of single inoculation of each isolate compared to the control. Grain yield was increased by 20.7– 96.5% over the control according to bacterial isolates. Available phosphorus (P) and counts of total bacteria in soil were observed to be significantly increased in treatments than in control. After the wheat harvest, soil pH was observed to be decreased, and a highly significant negative correlation was observed between soil pH and the levels of available phosphorus. Significant increases in grain and straw yields, as well as uptake of nitrogen (N) and P by plants, were observed due to inoculation with PGPR isolates. Levels of photosynthetic pigments, free amino acids, free phenolics, and reducing sugars in flag leaf and spikes were significantly enhanced by the application of all PGPR isolates compared to the control. Thus this study identifies the PGPR isolates for the improvement of the growth, yield, and quality of wheat. The study may be also useful for field evaluation under different soils and environmental conditions before generalising PGPR isolates as biofertilisers.
Eco-friendly role of serratia marcescens and pseudomonas fluorescens in enhancing rice growth and mitigating cadmium toxicity via uptake modulation and antioxidant regulation
Abstract Plant growth-promoting rhizobacteria (PGPR) offer sustainable means to enhance crop resilience under environmental stress, including heavy metal toxicity. Understanding their role in mitigating such stresses is vital for advancing biotechnological strategies aimed at food security and sustainable agriculture. A pot experiment was conducted to determine the effects of single and/or combined application of different levels [10 and 20 ppm] of Serratia marcescens and Pseudomonas fluorescens on Cd accumulation, morpho-physio-biochemical attributes of rice (Oryza sativa L.) exposed to severe Cd stress [0 (without Cd stress), and 100 µM)]. The research outcomes indicated that elevated levels of Cd stress in the soil significantly (p ≤ 0.05) decreased plant growth and biomass, photosynthetic pigments, and gas exchange attributes. However, Cd stress also induced oxidative stress in the plants by increasing malondialdehyde (MDA) and hydrogen peroxide (H2O2), which also induced increased compounds of various enzymatic and non-enzymatic antioxidants and also the gene expression and sugar content. Furthermore, a significant (p ≤ 0.05) increase in proline metabolism, the ascorbate–glutathione (AsA–GSH) cycle were observed. Although, the application of S. marcescens and P. fluorescens showed a significant (p ≤ 0.05) increase in plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds, and their gene expression and also decreased oxidative stress. In addition, the application of S. marcescens and P. fluorescens enhanced cellular fractionation and decreased the proline metabolism and AsA–GSH cycle in O. sativa plants. Research findings, therefore, suggest that the application of S. marcescens and P. fluorescens can ameliorate Cd toxicity in O. sativa, resulting in improved plant growth and composition under metal stress, as depicted by balanced antioxidant defense mechanism. Graphical Abstract
Crop stress detection from UAVs: best practices and lessons learned for exploiting sensor synergies
Introduction Detecting and monitoring crop stress is crucial for ensuring sufficient and sustainable crop production. Recent advancements in unoccupied aerial vehicle (UAV) technology provide a promising approach to map key crop traits indicative of stress. While using single optical sensors mounted on UAVs could be sufficient to monitor crop status in a general sense, implementing multiple sensors that cover various spectral optical domains allow for a more precise characterization of the interactions between crops and biotic or abiotic stressors. Given the novelty of synergistic sensor technology for crop stress detection, standardized procedures outlining their optimal use are currently lacking. Materials and methods This study explores the key aspects of acquiring high-quality multi-sensor data, including the importance of mission planning, sensor characteristics, and ancillary data. It also details essential data pre-processing steps like atmospheric correction and highlights best practices for data fusion and quality control. Results Successful multi-sensor data acquisition depends on optimal timing, appropriate sensor calibration, and the use of ancillary data such as ground control points and weather station information. When fusing different sensor data it should be conducted at the level of physical units, with quality flags used to exclude unstable or biased measurements. The paper highlights the importance of using checklists, considering illumination conditions and conducting test flights for the detection of potential pitfalls. Conclusion Multi-sensor campaigns require careful planning not to jeopardise the success of the campaigns. This paper provides practical information on how to combine different UAV-mounted optical sensors and discuss the proven scientific practices for image data acquisition and post-processing in the context of crop stress monitoring.
Ecophysiological variables retrieval and early stress detection: insights from a synthetic spatial scaling exercise
Sun-induced fluorescence spectrum as a tool for assessing peatland vegetation productivity in the framework of warming and reduced precipitation experiment
The effect of climate manipulation on CO2 fluxes in a temperate peatland: higher fluxes, more frequent irregularities, and seasonality displacements
High-throughput phenotyping of buckwheat (Fagopyrum esculentum Moench.) genotypes under water stress: exploring drought resistance for sustainable agriculture
Abstract Background As global agriculture faces the challenge of climate change, characterized by longer and more severe drought episodes, there is an increasing need for crop diversification and improved plant breeding. Buckwheat is one of the climate-resilient candidates for future important crops with remarkable adaptability to various biotic and abiotic stresses. As an underbred crop, a large number of genotypes should be assessed for the breeding of superior plants. Therefore, this study investigates the response of various buckwheat genotypes to water stress by high-throughput phenotyping and auxiliary plant physiology measurements. Results We assessed six buckwheat genotypes from different regions under mild and severe water stress, focusing on morphological and physiological changes to understand drought tolerance mechanisms. Our findings revealed that reallocation of assimilated carbon from growth to secondary metabolite production is a common response to drought stress. Among the genotypes tested, Panda emerged as the most drought-resistant, with its morphology remaining the most stable under mild water stress and its ability to rapidly accumulate protective pigments in response to drought. Silver Hull also demonstrated resilience, maintaining its aboveground biomass under mild water stress at levels comparable to the control group. Additionally, the response magnitude to drought stress was linked to the biomass production potential of the genotypes, which was higher for those from warmer regions (Bhutan, Zimbabwe) and lower for those from colder regions (Poland, Canada). Conclusion The diversity in genotypic responses highlights the significant role of genetic variability in shaping drought resistance strategies in buckwheat. This research not only enhances our understanding of buckwheat’s physiological responses to water stress but also holds promise for developing drought-resistant buckwheat varieties. These advancements are crucial for promoting sustainable agriculture in the face of climate change.
Photoinhibition in horticultural crops: an overview of the effect of light quality and signaling in the underlying photoprotection mechanisms
Mitigation effects of selenium on accumulation of cadmium and morpho-physiological properties in rice varieties
Cloud-Based Remote Sensing for Wetland Monitoring—A Review
The rapid expansion of remote sensing provides recent and developed advances in monitoring wetlands. Integrating cloud computing with these techniques has been identified as an effective tool, especially for dealing with heterogeneous datasets. In this study, we conducted a systematic literature review (SLR) to determine the current state-of-the-art knowledge for integrating remote sensing and cloud computing in the monitoring of wetlands. The results of this SLR revealed that platform-as-a-service was the only cloud computing service model implemented in practice for wetland monitoring. Remote sensing applications for wetland monitoring included prediction, time series analysis, mapping, classification, and change detection. Only 51% of the reviewed literature, focused on the regional scale, used satellite data. Additionally, the SLR found that current cloud computing and remote sensing technologies are not integrated enough to benefit from their potential in wetland monitoring. Despite these gaps, the analysis revealed that economic benefits could be achieved by implementing cloud computing and remote sensing for wetland monitoring. To address these gaps and pave the way for further research, we propose integrating cloud computing and remote sensing technologies with the Internet of Things (IoT) to monitor wetlands effectively.
Artificial neural network (ANN)-based algorithms for high light stress phenotyping of tomato genotypes using chlorophyll fluorescence features
Microbial allies in agriculture: harnessing plant growth-promoting microorganisms as guardians against biotic and abiotic stresses
Plants face many biological and non-biological challenges throughout their life cycle, from seed to harvest. These challenges have recently increased due to climate changes. Strategies for confronting different types of stresses depend on the type of stress, the cultivated plant, climatic conditions, soil characteristics, water variables, cost, and management system. Chemical methods (fertilizers and pesticides) have been widely used to manage abiotic and biotic stresses, but they raise concerns about environmental contamination, toxic residues, and the development of resistant pathogens. Eco-friendly strategies have recently become one of the most important approaches to obtaining high-quality and quantitative plant-based products. Microbial inoculants, such as plant growth-promoting microorganisms (PGPM), offer a sustainable alternative to chemical methods. PGPM can augment plant growth and nutrition, improve plant tolerance to abiotic stresses, and reduce the growth of certain pathogens. They employ a variety of mechanisms to alleviate stressors and boost plant resilience, including nutrient assimilation, production of metabolites, and activation of systemic resistance. This review aims to elucidate the impact of PGPM, with a particular focus on plant growth-promoting bacteria (PGPB), and their mechanisms of action on plants under varying stressors, while also identifying areas for further research in both PGPB and other non-bacterial organisms.
Dissecting the osmotic and oxidative stress responses in salt-tolerant and salt-sensitive wheat genotypes under saline conditions
Impact of climate change-induced alterations in peatland vegetation phenology and composition on carbon balance
Exploration of Genetic Pattern of Phenological Traits in Wheat (Triticum aestivum L.) under Drought Stress
Exogenous allantoin confers rapeseed (Brassica campestris) tolerance to simulated drought by improving antioxidant metabolism and physiology
Allantoin is an emerging plant metabolite, but its role in conferring drought-induced oxidative stress is still elusive. Therefore, an experiment was devised to explore the role of allantoin (0.5 and 1.0 mM; foliar spray) in rapeseed (Brassica campestris cv. BARI Sarisha-17) under drought. Seedlings at fifteen days of age were subjected to drought, maintaining soil moisture levels at 50% and 25% field capacities, while well-irrigated plants served as the control group. Drought-stressed plants exhibited increased levels of lipid peroxidation and hydrogen peroxide, electrolyte leakage, and impaired glyoxalase systems. Thus, the growth, biomass, and yield attributes of rapeseed were significantly impaired under drought. However, the allantoin-supplemented plants showed a notable increase in their contents of ascorbate and glutathione and decreased dehydroascorbate and glutathione disulfide contents under drought. Moreover, the activity of antioxidant enzymes such as ascorbate peroxidase, dehydroascorbate reductase, glutathione reductase, glutathione peroxidase, and catalase were accelerated with the allantoin spray and the glyoxalase system was also enhanced under drought. Moreover, the improvement in water balance with reduction in proline and potassium ion contents was also observed when allantoin was applied to the plants. Overall, the beneficial effects of allantoin supplementation resulted in the improved plant growth, biomass, and yield of rapeseed under drought conditions. These findings suggest that allantoin acts as an efficient metabolite in mitigating the oxidative stress caused by reactive oxygen species by enhancing antioxidant defense mechanisms and the glyoxalase system.
Carbon sequestrating fertilizers as a tool for carbon sequestration in agriculture under aridisols
Response to Cadmium Toxicity: Orchestration of Polyamines and microRNAs in Maize Plant
Cadmium (Cd) is a heavy metal that is widely contaminating the environment due to its uses in industries as corrosive reagents, paints, batteries, etc. Cd can easily be absorbed through plant roots and may have serious negative impacts on plant growth. To investigate the mechanisms utilized by plants to cope with Cd toxicity, an experiment was conducted on maize seedlings. We observed that the plant growth and photosynthetic mechanism were negatively influenced during 20 days of Cd stress. The expression levels of ornithine decarboxylase (ORDC) increased in the six seedlings under Cd exposure compared to the control. However, Cd toxicity led to an increase in putrescine (Put) content only on day 15 when compared to the control plants. In fact, with the exception of day 15, the increases in the ORDC transcript levels did not show a direct correlation with the observed increases in Put content. Spermidine and Spermine levels were reduced on day 6 by Cd application, which was parallel with suppressed Spermidine synthase gene. However, an increase in Spermidine and Spermine levels was observed on day 12 along with a significant elevation in Spermidine synthase expression. On day 6, Cd was observed to start accumulating in the root with an increase in the expression of microRNA 528; while on day 15, Cd started to be observed in the shoot part with an increase in microRNA 390 and microRNA 168. These results imply that different miRNAs may regulate polyamines (PAs) in maize under Cd toxicity, suggesting a plant-derived strategy to commit a PAs/miRNA-regulated mechanism/s in different developmental stages (time points) in response to Cd exposure.
