Effects of biomass co-pyrolysis and herbaceous plant colonization on the transformation of tailings into soil like substrate.

Enhancing soil organic matter characteristics, ameliorating physical structure, mitigating heavy metal toxicity, and hastening mineral weathering processes are crucial approaches to accomplish the transition of tailings substrate to a soil-like substrate. The incorporation of biomass co-pyrolysis and plant colonization has been established to be a significant factor in soil substrate formation and soil pollutant remediation. Despite this, there is presently an absence of research efforts aimed at synergistically utilizing these two technologies to expedite the process of mining tailings soil substrate formation. The current study aimed to investigate the underlying mechanism of geochemical changes and rapid mineral weathering during the process of transforming tailings substrate into a soil-like substrate, under the combined effects of biomass co-smoldering pyrolysis and plant colonization. The findings of this study suggest that the incorporation of smoldering pyrolysis and plant colonization induces a high-temperature effect and biological effects, which enhance the physical and chemical properties of tailings, while simultaneously accelerating the rate of mineral weathering. Notable improvements include the amelioration of extreme pH levels, nutrient enrichment, the formation of aggregates, and an increase in enzyme activity, all of which collectively demonstrate the successful attainment of tailings substrate reconstruction. Evidence of the accelerated weathering was verified by phase and surface morphology analysis using X-ray diffraction and scanning electron microscopy. Discovered corrosion and fragmentation on the surface of minerals. The weathering resulted in corrosion and fragmentation of the surface of the treated mineral. This study confirms that co-smoldering pyrolysis of biomass, combined with plant colonization, can effectively promote the transformation of tailings into soil-like substrates. This method has can effectively address the key challenges that have previously hindered sustainable development of the mining industry and provides a novel approach for ecological restoration of tailings deposits.

Demographic but not competitive time lags can transiently amplify climate-induced changes in vegetation carbon storage.

How terrestrial ecosystems will accumulate carbon as the climate continues to change is a major source of uncertainty in projections of future climate. Under growth-stimulating environmental change, time lags inherent in population and community dynamic processes have been posed to dampen, or alternatively amplify, short-term carbon gain in terrestrial vegetation, but these outcomes can be difficult to predict. To theoretically frame this problem, we developed a simple model of vegetation dynamics that identifies the stage-structured demographic and competitive processes that could govern the timescales of carbon storage and loss. We show that demographic lags associated with growth-stimulating environmental change can allow a rapid increase in population-level carbon storage that is lost back to the atmosphere in later years. However, this transient carbon storage only emerges when environmental change increases the transition of adult individuals into a larger size class that suffers markedly higher mortality. Otherwise, demographic lags simply slow carbon accumulation. Counterintuitively, an analogous tradeoff between maximum adult size and survivorship in two-species models, coupled with environmental change-driven replacement, does not generate the transient carbon gain seen in the single-species models. Instead lags in competitive replacement slow the approach to the eventual carbon trajectory. Together, our results suggest that time lags inherent in demographic and compositional turnover tend to slow carbon accumulation in systems responding to growth-stimulating environmental change. Only under specific conditions will lagged demographic processes in such systems drive transient carbon accumulation, conditions that investigators can examine in nature to help project future carbon trajectories.

OPDA/dn-OPDA actions: biosynthesis, metabolism, and signaling.

Plants cannot move, so they have evolved sophisticated strategies that integrate the external environmental cues and internal signaling networks for adaptation to dynamic circumstances. Cis-(+)-12-oxo-phytodienoic acid (OPDA) and 2,3-dinor-OPDA (dn-OPDA), the cyclopentenone-containing oxylipins, ubiquitously occur in the green lineage to orchestrate a series of growth and developmental processes as well as various stress and defense responses. OPDA/dn-OPDA are precursors of jasmonate (JA) biosynthesis in vascular plants. Dn-OPDA and its isomer also serve as bioactive JAs perceived by the coronatine insensitive 1/jasmonate ZIM-domain (COI1/JAZ) co-receptor complex in bryophytes and lycophytes. In addition, OPDA/dn-OPDA display signaling activities independent of (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile) and COI1 in both vascular and non-vascular plants. In this review, we discuss recent advances in the biosynthesis, metabolism, and signaling of OPDA/dn-OPDA, and provide an overview of the evolution of OPDA/dn-OPDA actions to obtain a deeper understanding of the pervasive role of OPDA/dn-OPDA in the plant life cycle.

Employment of pqqE gene as molecular marker for the traceability of Gram negative phosphate solubilizing bacteria associated to plants.

Insoluble phosphorous compounds solubilization by soil bacteria is of great relevance since it puts available the phosphorus to be used by plants. The production of organic acids is the main microbiological mechanism by which insoluble inorganic phosphorus compounds are solubilized. In Gram negative bacteria, gluconic acid is synthesized by the activity of the holoenzyme glucose dehydrogenase-pyrroloquinoline quinine named GDH-PQQ. The use of marker genes is a very useful tool to evaluate the persistence of the introduced bacteria and allow to follow-up the effect of biotic and abiotic factors on these beneficial microorganisms in the soil. In previous studies we detected the presence of the pqqE gene in a great percentage of both non-culturable and culturable native soil bacteria. The objective of this study was to analyze the phylogeny of the sequence of pqqE gene and its potential for the study of phosphate solubilizing bacteria from pure and mixed bacterial cultures and rhizospheric soil samples. For this, the presence of the pqqE gene in the genome of phosphate solubilizing bacteria that belong to several bacteria was determined by PCR. Also, this gene was analyzed from mixed bacterial cultures and rhizospheric soil associated to peanut plants inoculated or not with phosphate solubilizing bacteria. For this, degenerate primers designed from several bacterial genera and specific primers for the genus Pseudomonas spp., designed in this study, were used. DNA template used from simple or mixed bacterial cultures and from rhizospheric soil samples was obtained using two different DNA extraction techniques. Results indicated that pqqE gene amplification product was found in the genome of all Gram negative phosphate solubilizing bacteria analyzed. It was possible to detect this gene in the DNA obtained from mixed cultures where these bacteria grew in interaction with other microorganisms and in that obtained from rhizospheric soil samples inoculated or not with these bacteria. The phylogenetic analysis indicated that pqqE gene is a conserved gene within related genera. In conclusion, pqqE gene could be a potential marker for the study of phosphate solubilizing bacterial populations.

Temporal variation characteristics in the association between climate and vegetation in Northwest China.

Northwest China has undergone notable alterations in climate and vegetation growth in recent decades. Nevertheless, uncertainties persist concerning the response of different vegetation types to climate change and the underlying mechanisms. This study utilized the Normalized Difference Vegetation Index (NDVI) and three sets of meteorological data to investigate the interannual variations in the association between vegetation and climate (specifically precipitation and temperature) from 1982 to 2015. Several conclusions were drawn. (1) RNDVI-GP (relationship between Growing Season NDVI and precipitation) decreased significantly across all vegetation, while RNDVI-GT (relationship between Growing Season NDVI and temperature) showed an insignificant increase. (2) Trends of RNDVI-GP and RNDVI-GT exhibited great variations across various types of vegetation, with forests displaying notable downward trends in both indices. The grassland exhibited a declining trend in RNDVI-GP but an insignificant increase in RNDVI-GT, while no significant temporal changes in RNDVI-GP or RNDVI-GT were observed in the barren land. (3) The fluctuations in RNDVI-GP and RNDVI-GT closely aligned with variations in drought conditions. Specifically, in regions characterized by VPD (vapor pressure deficit) trends less than 0.02 hpa/yr, which are predominantly grasslands, a rise in SWV (soil water volume) tended to cause a reduction in RNDVI-GP but an increase in RNDVI-GT. However, a more negative trend in SWV was associated with a more negative trend in both RNDVI-GP and RNDVI-GT when the VPD trend exceeded 0.02 hPa/yr, primarily in forests. Our results underscore the variability in the relationship between climate change and vegetation across different vegetation types, as well as the role of drought in modulating these associations.

Coming of age for Microbiome gene breeding in plants.

The plant microbiota can complement host functioning, leading to improved growth and health under unfavorable conditions. Microbiome engineering could therefore become a transformative technique for crop production. Microbiome genes, abbreviated as M genes, provide valuable targets for shaping plant-associated microbial communities.

New Insights into Involvement of Low Molecular Weight Proteins in Complex Defense Mechanisms in Higher Plants.

Dynamic climate changes pose a significant challenge for plants to cope with numerous abiotic and biotic stressors of increasing intensity. Plants have evolved a variety of biochemical and molecular defense mechanisms involved in overcoming stressful conditions. Under environmental stress, plants generate elevated amounts of reactive oxygen species (ROS) and, subsequently, modulate the activity of the antioxidative enzymes. In addition, an increase in the biosynthesis of important plant compounds such as anthocyanins, lignin, isoflavonoids, as well as a wide range of low molecular weight stress-related proteins (e.g., dehydrins, cyclotides, heat shock proteins and pathogenesis-related proteins), was evidenced. The induced expression of these proteins improves the survival rate of plants under unfavorable environmental stimuli and enhances their adaptation to sequentially interacting stressors. Importantly, the plant defense proteins may also have potential for use in medical applications and agriculture (e.g., biopesticides). Therefore, it is important to gain a more thorough understanding of the complex biological functions of the plant defense proteins. It will help to devise new cultivation strategies, including the development of genotypes characterized by better adaptations to adverse environmental conditions. The review presents the latest research findings on selected plant defense proteins.

Melatonin-Nitric Oxide Crosstalk in Plants and the Prospects of NOMela as a Nitric Oxide Donor.

Melatonin regulates vital physiological processes in animals, such as the circadian cycle, sleep, locomotion, body temperature, food intake, and sexual and immune responses. In plants, melatonin modulates seed germination, longevity, circadian cycle, photoperiodicity, flowering, leaf senescence, postharvest fruit storage, and resistance against biotic and abiotic stresses. In plants, the effect of melatonin is mediated by various regulatory elements of the redox network, including RNS and ROS. Similarly, the radical gas NO mediates various physiological processes, like seed germination, flowering, leaf senescence, and stress responses. The biosynthesis of both melatonin and NO takes place in mitochondria and chloroplasts. Hence, both melatonin and nitric oxide are key signaling molecules governing their biological pathways independently. However, there are instances when these pathways cross each other and the two molecules interact with each other, resulting in the formation of N-nitrosomelatonin or NOMela, which is a nitrosated form of melatonin, discovered recently and with promising roles in plant development. The interaction between NO and melatonin is highly complex, and, although a handful of studies reporting these interactions have been published, the exact molecular mechanisms governing them and the prospects of NOMela as a NO donor have just started to be unraveled. Here, we review NO and melatonin production as well as RNS-melatonin interaction under normal and stressful conditions. Furthermore, for the first time, we provide highly sensitive, ozone-chemiluminescence-based comparative measurements of the nitric oxide content, as well as NO-release kinetics between NOMela and the commonly used NO donors CySNO and GSNO.

Predicting undetected native vascular plant diversity at a global scale.

Vascular plants are diverse and a major component of terrestrial ecosystems, yet their geographic distributions remain incomplete. Here, I present a global database of vascular plant distributions by integrating species distribution models calibrated to species' dispersal ability and natural habitats to predict native range maps for 201,681 vascular plant species into unsurveyed areas. Using these maps, I uncover unique patterns of native vascular plant diversity, endemism, and phylogenetic diversity revealing hotspots in underdocumented biodiversity-rich regions. These hotspots, based on detailed species-level maps, show a pronounced latitudinal gradient, strongly supporting the theory of increasing diversity toward the equator. I trained random forest models to extrapolate diversity patterns under unbiased global sampling and identify overlaps with modeled estimations but unveiled cryptic hotspots that were not captured by modeled estimations. Only 29% to 36% of extrapolated plant hotspots are inside protected areas, leaving more than 60% outside and vulnerable. However, the unprotected hotspots harbor species with unique attributes that make them good candidates for conservation prioritization.

Methods for Assessing Plant Immune System Activation by Bacterial Extracellular Vesicles and Other Elicitors.

Bacterial extracellular vesicles (BEVs) are released from the surface of bacterial cells and contain a diverse molecular cargo. Studies conducted primarily with bacterial pathogens of mammals have shown that BEVs are involved in multiple processes such as cell-cell communication, the delivery of RNA, DNA, and proteins to target cells, protection from stresses, manipulation of host immunity, and other functions. Until a decade ago, the roles of BEVs in plant-bacteria interactions were barely investigated. However, recent studies have shown that BEVs of plant pathogens possess similar functions as their mammalian pathogen counterparts, and more research is now devoted to study their roles and interactions with plants. In the following methods chapter, we provide five well-validated assays to examine the interaction of BEVs with the plant immune system. These assays rely on different markers or immune outputs, which indicate the activation of plant immunity (defense marker gene expression, reactive oxygen species burst, seedling inhibition). Furthermore, we offer assays that directly evaluate the priming of the immune system following BEV challenge and the effectiveness of its response to subsequent local or systemic infection. Altogether, these assays provide a thorough examination to the interactions of BEVs and the plant immune system.

Prospects of phosphate solubilizing microorganisms in sustainable agriculture.

Phosphorus (P), an essential macronutrient for various plant processes, is generally a limiting soil component for crop growth and yields. Organic and inorganic types of P are copious in soils, but their phyto-availability is limited as it is present largely in insoluble forms. Although phosphate fertilizers are applied in P-deficit soils, their undue use negatively impacts soil quality and the environment. Moreover, many P fertilizers are lost because of adsorption and fixation mechanisms, further reducing fertilizer efficiencies. The application of phosphate-solubilizing microorganisms (PSMs) is an environmentally friendly, low-budget, and biologically efficient method for sustainable agriculture without causing environmental hazards. These beneficial microorganisms are widely distributed in the rhizosphere and can hydrolyze inorganic and organic insoluble P substances to soluble P forms which are directly assimilated by plants. The present review summarizes and discusses our existing understanding related to various forms and sources of P in soils, the importance and P utilization by plants and microbes,, the diversification of PSMs along with mixed consortia of diverse PSMs including endophytic PSMs, the mechanism of P solubilization, and lastly constraints being faced in terms of production and adoption of PSMs on large scale have also been discussed.

Evaluation of the Reliability of the CCM-300 Chlorophyll Content Meter in Measuring Chlorophyll Content for Various Plant Functional Types.

Chlorophyll fluorescence is a well-established method to estimate chlorophyll content in leaves. A popular fluorescence-based meter, the Opti-Sciences CCM-300 Chlorophyll Content Meter (CCM-300), utilizes the fluorescence ratio F735/F700 and equations derived from experiments using broadleaf species to provide a direct, rapid estimate of chlorophyll content used for many applications. We sought to quantify the performance of the CCM-300 relative to more intensive methods, both across plant functional types and years of use. We linked CCM-300 measurements of broadleaf, conifer, and graminoid samples in 2018 and 2019 to high-performance liquid chromatography (HPLC) and/or spectrophotometric (Spec) analysis of the same leaves. We observed a significant difference between the CCM-300 and HPLC/Spec, but not between HPLC and Spec. In comparison to HPLC, the CCM-300 performed better for broadleaves (r = 0.55, RMSE = 154.76) than conifers (r = 0.52, RMSE = 171.16) and graminoids (r = 0.32, RMSE = 127.12). We observed a slight deterioration in meter performance between years, potentially due to meter calibration. Our results show that the CCM-300 is reliable to demonstrate coarse variations in chlorophyll but may be limited for cross-plant functional type studies and comparisons across years.

Micronutrient deficiency-induced oxidative stress in plants.

Micronutrients like iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), boron (B), nickel (Ni), and molybdenum (Mo) perform significant roles in the regulation of plant metabolism, growth, and development. Micronutrients, namely Fe, Zn, Cu, Mn, and Ni, are involved in oxidative stress and antioxidant defense as they are cofactors or activators of various antioxidant enzymes, viz., superoxide dismutase (Fe, Cu/Zn, Mn, and Ni), catalase (Fe), and ascorbate peroxidase (Fe). An effort has been made to incorporate recent advances along with classical work done on the micronutrient deficiency-induced oxidative stress and associated antioxidant responses of plants. Deficiency of a micronutrient produces ROS in the cellular compartments. Enzymatic and non-enzymatic antioxidant defense systems are often modulated by micronutrient deficiency to regulate redox balance and scavenge deleterious ROS for the safety of cellular constituents. ROS can strike cellular constituents such as lipids, proteins, and nucleic acids and can destruct cellular membranes and proteins. ROS might act as a signaling molecule and activate the antioxidant proteins by interacting with signaling partners such as respiratory burst oxidase homolog (RBOH), G-proteins, Ca2+, mitogen activated protein kinases (MAPKs), and various transcription factors (TFs). Opinions on probable ROS signaling under micronutrient deficiency have been described in this review. However, further research is required to decipher micronutrient deficiency-induced ROS generation, perception, and associated downstream signaling events, leading to the development of antioxidant responses in plants.

Significance of AI-assisted techniques for epiphyte plant monitoring and identification from drone images.

Monitoring forest canopies is vital for ecological studies, particularly for assessing epiphytes in rain forest ecosystems. Traditional methods for studying epiphytes, such as climbing trees and building observation structures, are labor, cost intensive and risky. Unmanned Aerial Vehicles (UAVs) have emerged as a valuable tool in this domain, offering botanists a safer and more cost-effective means to collect data. This study leverages AI-assisted techniques to enhance the identification and mapping of epiphytes using UAV imagery. The primary objective of this research is to evaluate the effectiveness of AI-assisted methods compared to traditional approaches in segmenting/identifying epiphytes from UAV images collected in a reserve forest in Costa Rica. Specifically, the study investigates whether Deep Learning (DL) models can accurately identify epiphytes during complex backgrounds, even with a limited dataset of varying image quality. Systematically, this study compares three traditional image segmentation methods Auto Cluster, Watershed, and Level Set with two DL-based segmentation networks: the UNet and the Vision Transformer-based TransUNet. Results obtained from this study indicate that traditional methods struggle with the complexity of vegetation backgrounds and variability in target characteristics. Epiphyte identification results were quantitatively evaluated using the Jaccard score. Among traditional methods, Watershed scored 0.10, Auto Cluster 0.13, and Level Set failed to identify the target. In contrast, AI-assisted models performed better, with UNet scoring 0.60 and TransUNet 0.65. These results highlight the potential of DL approaches to improve the accuracy and efficiency of epiphyte identification and mapping, advancing ecological research and conservation.

Advances in Understanding the Toxicity of 4-Hydroxyphenylpyruvate Dioxygenase-Inhibiting Herbicides.

4-Hydroxyphenylpyruvate dioxygenase inhibiting herbicides (HIHs) represent a recent class (HRAC group 27) of herbicides that offer many advantages, such as broad-spectrum activity, crop selectivity, and low resistance rates. However, emerging studies have highlighted the potential toxicity of HIHs in the environment. This review aims to provide a comprehensive summary of the toxicity of HIHs toward nontarget organisms, including plants, microorganisms, animals, and humans. Furthermore, the present work discusses the ecological roles of these organisms in the environment and their significance in agriculture. By shedding light on the toxicity of HIHs, this study seeks to raise awareness among end users, including environmentalists, researchers, and farmers, regarding the potential ecological implications of these herbicides. Hopefully, this knowledge can contribute to informed decision-making and sustainable practices in green agriculture and environmental management.

Integrating viruses into soil food web biogeochemistry.

The soil microbiome is recognized as an essential component of healthy soils. Viruses are also diverse and abundant in soils, but their roles in soil systems remain unclear. Here we argue for the consideration of viruses in soil microbial food webs and describe the impact of viruses on soil biogeochemistry. The soil food web is an intricate series of trophic levels that span from autotrophic microorganisms to plants and animals. Each soil system encompasses contrasting and dynamic physicochemical conditions, with labyrinthine habitats composed of particles. Conditions are prone to shifts in space and time, and this variability can obstruct or facilitate interactions of microorganisms and viruses. Because viruses can infect all domains of life, they must be considered as key regulators of soil food web dynamics and biogeochemical cycling. We highlight future research avenues that will enable a more robust understanding of the roles of viruses in soil function and health.

Advances in functional studies of plant MYC transcription factors.

Myelocytomatosis (MYC) transcription factors (TFs) belong to the basic helix-loop-helix (bHLH) family in plants and play a central role in governing a wide range of physiological processes. These processes encompass plant growth, development, adaptation to biotic and abiotic stresses, as well as secondary metabolism. In recent decades, significant strides have been made in comprehending the multifaceted regulatory functions of MYCs. This advancement has been achieved through the cloning of MYCs and the characterization of plants with MYC deficiencies or overexpression, employing comprehensive genome-wide 'omics' and protein-protein interaction technologies. MYCs act as pivotal components in integrating signals from various phytohormones' transcriptional regulators to orchestrate genome-wide transcriptional reprogramming. In this review, we have compiled current research on the role of MYCs as molecular switches that modulate signal transduction pathways mediated by phytohormones and phytochromes. This comprehensive overview allows us to address lingering questions regarding the interplay of signals in response to environmental cues and developmental shift. It also sheds light on the potential implications for enhancing plant resistance to diverse biotic and abiotic stresses through genetic improvements achieved by plant breeding and synthetic biology efforts.