Consequences For Plants Research Articles

Nanoparticles as a Tool for Alleviating Plant Stress: Mechanisms, Implications, and Challenges.

Plants, being sessile, are continuously exposed to varietal environmental stressors, which consequently induce various bio-physiological changes in plants that hinder their growth and development. Oxidative stress is one of the undesirable consequences in plants triggered due to imbalance in their antioxidant defense system. Biochemical studies suggest that nanoparticles are known to affect the antioxidant system, photosynthesis, and DNA expression in plants. In addition, they are known to boost the capacity of antioxidant systems, thereby contributing to the tolerance of plants to oxidative stress. This review study attempts to present the overview of the role of nanoparticles in plant growth and development, especially emphasizing their role as antioxidants. Furthermore, the review delves into the intricate connections between nanoparticles and plant signaling pathways, highlighting their influence on gene expression and stress-responsive mechanisms. Finally, the implications of nanoparticle-assisted antioxidant strategies in sustainable agriculture, considering their potential to enhance crop yield, stress tolerance, and overall plant resilience, are discussed.

Application of Arabidopsis thaliana in the Remediation of Soil Pollution : Evidence from the Earthworm-Microbe-Arabidopsis System

ABSTRACT Presence of cadmium in soil affects the growth status of plants; research on the underlying mechanism has focused on its lethal and sublethal consequences in plants, ignoring the impacts of soil organisms. Therefore, this study designed a microorganism – earthworm – plant ecosystem, investigated the influence of Cd (0, 0.3, 1.0, and 3.0 mg kg−1) on the growth of Arabidopsis thaliana in the presence of earthworms (Eisenia fetida), and revealed the mechanisms from the perspective of altered relationships among different soil organisms. In this study, there was no significant difference in the death rate of earthworms with low Cd addition concentration, but the microorganisms in earthworms and soil microorganisms changed, abundance of Actinomycetes in soil increased, while Planctomycetes decreased, Mycobacterium in the gut of Eisenia fetida decreased under Cd stress. Microorganisms affect soil pH, which in turn affects soil physicochemical properties and the form of cadmium in soil. Compared with the control, soil pH significantly decreases under cadmium stress, Under 0.3 mg kg−1 treatment, soil total nitrogen, available phosphorus and total potassium are 181.11, 5.09, 51.90, and 7.55 mg kg−1, respectively, They were significantly higher than control group. Improved the growth environment of Arabidopsis thaliana and promoted the absorption of Cd in soil which affected the proportion of available Cd in the soil (when Cd was added at 1.0 mg kg−1, the proportion of available Cd in the soil decreased significantly from 95.05% to 49.40%). A. thaliana also absorbed more Cd, which increased Cd toxicity, and the reproductive growth of A. thaliana was enhanced, while vegetative growth was weakened.Compared with the control group (278.11 mg), the biomass of A. thaliana decreased significantly to 189.83 mg when Cd was supplemented at 0.3 mg kg−1. Therefore, the activities of and interactions among earthworms, plants, and microorganisms play important roles in reducing soil heavy metals and improving soil properties.

A practical exploration of land cover impacts on surface and air temperature when they are most consequential

Widespread shifts in land cover and land management (LCLM) are being incentivized as tools to mitigate climate change, creating an urgent need for prognostic assessments of how LCLM impacts surface energy balance and temperature. Historically, observational studies have tended to focus on how LCLM impacts surface temperature (T surf), usually at annual timescales. However, understanding the potential for LCLM change to confer climate adaptation benefits, or to produce unintended adverse consequences, requires careful consideration of impacts on both T surf and the near-surface air temperature (T a,local) when they are most consequential for ecosystem and societal well-being (e.g. on hot summer days). Here, long-term data from 130 AmeriFlux towers distributed between 19–71 °N are used to systematically explore LCLM impacts on both T surf and T a,local, with an explicit focus on midday summer periods when adaptive cooling is arguably most needed. We observe profound impacts of LCLM on T surf at midday, frequently amounting to differences of 10 K or more from one site to the next. LCLM impacts on T a,local are smaller but still significant, driving variation of 5–10 K across sites. The magnitude of LCLM impacts on both T surf and T a,local is not well explained by plant functional type, climate regime, or albedo; however, we show that LCLM shifts that enhance ET or increase canopy height are likely to confer a local mid-day cooling benefit for both T surf and T a,local most of the time. At night, LCLM impacts on temperature are much smaller, such that averaging across the diurnal cycle will underestimate the potential for land cover to mediate microclimate when the consequences for plant and human well-being are most stark. Finally, during especially hot periods, land cover impacts on T a,local and T surf are less coordinated, and ecosystems that tend to cool the air during normal conditions may have a diminished capacity to do so when it is very hot. We end with a set of practical recommendations for future work evaluating the biophysical impacts and adaptation potential of LCLM shifts.

The pollen virome: A review of pollen-associated viruses and consequences for plants and their interactions with pollinators.

The movement of pollen grains from anthers to stigmas, often by insect pollinator vectors, is essential for plant reproduction. However, pollen is also a unique vehicle for viral spread. Pollen-associated plant viruses reside on the outside or inside of pollen grains, infect susceptible individuals through vertical or horizontal infection pathways, and can decrease plant fitness. These viruses are transferred with pollen between plants by pollinator vectors as they forage for floral resources; thus, pollen-associated viral spread is mediated by floral and pollen grain phenotypes and pollinator traits, much like pollination. Most of what is currently known about pollen-associated viruses was discovered through infection and transmission experiments in controlled settings, usually involving one virus and one plant species of agricultural or horticultural interest. In this review, we first provide an updated, comprehensive list of the recognized pollen-associated viruses. Then, we summarize virus, plant, pollinator vector, and landscape traits that can affect pollen-associated virus transmission,infection, and distribution. Next, we highlight the consequences of plant-pollinator-virus interactions that emerge in complex communities of co-flowering plants and pollinator vectors, such as pollen-associated virus spread between plant species and viral jumps from plant to pollinator hosts. We conclude by emphasizing the need for collaborative research that bridges pollen biology, virology, and pollination biology.

Genotype and environment effects on sunflower nectar and their relationships to crop pollination

Whether caused by genotype (G) or environment (E), floral trait variation has consequences for plants and their pollinators. Cultivated sunflower is a model system to explore floral trait variation; though sunflowers are bred to self-pollinate, benefits of pollination by bees remain substantial. To better understand sunflower-pollinator interactions, experiments were conducted to: (i) examine genotype and environment effects on nectar quantity and quality under controlled conditions, and (ii) assess effects of bags used for pollinator exclusion on nectar quantity, quality and bee foraging in a field environment. Contrasting temperature treatments (28°C, 21°C, 28°C / 16°C) reveal environment effects or G × E interactions for nectar volume (µl / floret), concentration (°Brix), and sugar composition (% sucrose). Bags used to exclude sunflower pollinators resulted in nectar volumes greater than plants with unrestricted access for bees (= open-pollination), and in ≈ 5-fold increased visitation by wild bees after bags were removed. Differences in bee visits to plants that were previously bagged versus plants never bagged decreased over the 2 h following bag removal. Though genetic variation in sunflower nectar is affected by the environment and G × E interactions, improving pollination via plant breeding still appears feasible. Future research on intraspecific variation in pollen rewards could be helpful, especially because pollen has received little research compared to nectar. For research with nectar or pollen, it seems desirable to measure floral rewards with methods that don’t rely on pollinator exclusion (bags or cages), which should provide more realistic data on what pollinators experience while foraging.

Revisiting plant defense-fitness trade-off hypotheses using Solanum as a model genus

Plants possess physical and chemical defenses which have been found to deter herbivores that feed and oviposit on them. Despite having wide variety of defenses which can be constitutive or induced, plants are attacked and damaged by insects associated with different mouthparts and feeding habits. Since these defenses are costly, trade-offs for growth and defense traits play an important role in warding off the herbivores, with consequences for plant and herbivore growth, development and fitness. Solanum is a diverse and rich genus comprising of over 1,500 species with economic and ecological importance. Although a large number of studies on Solanum species with different herbivores have been carried out to understand plant defenses and herbivore counter defenses, they have primarily focused on pairwise interactions, and a few species of economic and ecological importance. Therefore, a detailed and updated understanding of the integrated defense system (sum of total defenses and trade-offs) is still lacking. Through this review, we take a closer look at the most common plant defense hypotheses, their assumptions and trade-offs and also a comprehensive evaluation of studies that use the genus Solanum as their host plant, and their generalist and specialist herbivores from different feeding guilds. Overall, review emphasizes on using ubiquitous Solanum genus and working toward building an integrated model which can predict defense-fitness-trade-offs in various systems with maximum accuracy and minimum deviations from realistic results.

Carbon nanotube-based nano-biosensors for detecting heavy metals in the aquatic environment.

The identification of harmful metal ions in aquatic environments is a global concern since these contaminants can have serious consequences for plants, animals, humans, and ecosystems. A biosensor is a type of analytical equipment that combines a biological recognition element and a physical transducer to detect biological signals to produce a detectable indication proportionate to the concentration of the samples being analysed. The analyte spreads from the fluid to the biosensor's superficial. The analyte responds precisely and competently with the biosensor's biological component. The physicochemical properties of the transducer surface change as a result of this process. The visual or electric properties of the transducer surface alter as a result of this. The signal that is detected is an electrical signal. With the help of carbon-based nano-biosensors, metals from the aquatic environment can easily be detected, which is much simpler, less time-consuming, and less expensive as well.

Plant and herbivorous insect communities respond in complex ways to rainfall manipulation in an oak savanna grassland

Abstract Changes in precipitation due to climate change will have consequences for plant and herbivorous insect communities alike. Multiple hypotheses explain how changes in plant diversity and productivity can lead to changes in herbivore community composition. Yet as rainfall patterns change, the bottom‐up effects on the relationships between plant and herbivore communities are less well understood. Using a long‐term rainfall manipulation experiment in a remnant patch of Garry oak (Quercus garryana) savanna, we examined how plant diversity and productivity have responded to variation in soil moisture over 6 years. This highly endangered ecosystem is predicted to experience significantly wetter springs and drier summers by 2080. We also investigated plant‐mediated, indirect effects of manipulated rainfall on herbivore diversity and abundance, drawing on multiple hypotheses describing the relationships between plant and herbivore communities. For example, the more individuals hypothesis predicts that increased plant productivity results in increased herbivore abundance which, in turn, results in increased herbivore diversity. We found that plant productivity was influenced by soil moisture, but the direction and magnitude of the response varied across years, and found no support for plant diversity influencing productivity. We also found that the cover and productivity of grasses increased significantly with increasing precipitation. In addition to a direct negative effect on herbivore diversity, soil moisture had an indirect negative effect on herbivore abundance, via the negative effect of plant productivity on abundance, contradicting the more individuals hypothesis. Synthesis. Our results highlight that not only can drought result in significant reductions in plant productivity in this threatened ecosystem, but that these changes will also result in increases in herbivore abundance. In contrast, where soil moisture is higher, grasses will become more dominant resulting in decreased herbivore abundance. Ultimately, predicting how this system responds to changes in precipitation will depend on the ability to predict whether growing season soil moisture will be consistently drier or wetter in the future, a significant challenge. Going forward, investigating how variation in precipitation due to climate change affects the links between trophic levels, including how herbivores affect plant communities, remains critical for understanding ecosystem processes and stability.

Dirt cheap: an experimental test of controls on resource exchange in an ectomycorrhizal symbiosis.

To distinguish among hypotheses on the importance of resource-exchange ratios in outcomes of mutualisms, we measured resource (carbon (C), nitrogen (N), and phosphorus (P)) transfers and their ratios, between Pinus taeda seedlings and two ectomycorrhizal (EM) fungal species, Rhizopogon roseolus and Pisolithus arhizus in a laboratory experiment. We evaluated how ambient light affected those resource fluxes and ratios over three time periods (10, 20, and 30 wk) and the consequences for plant and fungal biomass accrual, in environmental chambers. Our results suggest that light availability is an important factor driving absolute fluxes of N, P, and C, but not exchange ratios, although its effects vary among EM fungal species. Declines in N:C and P:C exchange ratios over time, as soil nutrient availability likely declined, were consistent with predictions of biological market models. Absolute transfer of P was an important predictor of both plant and fungal biomass, consistent with the excess resource-exchange hypothesis, and N transfer to plants was positively associated with fungal biomass. Altogether, light effects on resource fluxes indicated mixed support for various theoretical frameworks, while results on biomass accrual better supported the excess resource-exchange hypothesis, although among-species variability is in need of further characterization.

Pleiotropic effects of recombinant protease inhibitors in plants.

Recombinant gene encoded protease inhibitors have been identified as some of the most effective antidigestive molecules to guard against proteolysis of essential proteins and plant attacking proteases from herbivorous pests and pathogenic microorganisms. Protease inhibitors (PIs) can be over expressed in transgenic plants to complement internal host defense systems, Bt toxins in genetically modified pest resistance and abiotic stress tolerance achieved through cystatins expression. Although the understanding of the role of proteolytic enzymes and their inhibitors encoded by both endogenous and transgenes expressed in crop plants has significantly advanced, their implication in biological systems still requires further elucidations. This paper, therefore, succinctly reviewed most recently published literature on recombinant proteases inhibitors (RPIs), focusing mainly on their unintended consequences in plants, other living organisms, and the environment. The review discusses major negative and unintended effects of RPIs involving the inhibitors’ non-specificity on protease enzymes, non-target organisms and ubiquitous versatility in their mechanism of inhibition. The paper also discusses some direct and indirect effects of RPIs such as degradation by distinct classes of proteases, reduced functionality due to plant exposure to severe environmental stress and any other potential negative influences exerted on both the host plant as well as the environment. These pleiotropic effects must be decisively monitored to eliminate and prevent any potential adverse effects that transgenic plants carrying recombinant inhibitor genes may have on non-target organisms and biodiversity.

Effects of honeybee (Apis cerana) visiting behaviour on toxic plant (Tripterygium hypoglaucum) reproduction.

Honeybees play a significant role in the plant–pollinator interactions of many flowering plants. The ecological and evolutionary consequences of plant–pollinator interactions vary by geographic region, and the effects of honeybees on the reproduction of toxic plants have not been well studied. We measured the florescence of toxic plants, the flower-visiting behaviour of honeybees and the effects of pollination on the fertility, weight and moisture content of seeds. The effects of climatic factors on the number of flowers, and the spatial and temporal variation in pollinator visits were evaluated, and the effects of pollinator visits on seed quality were evaluated. Flower visitors were diverse, climatic factors had a great impact on spatio-temporal flowering variation and the number of bee visits was strongly correlated with the spatio-temporal variation in the number of flowers. Honeybees strongly increase the fullness and weight of seeds. Our study demonstrated a good ecological fit between the spatio-temporal variation in the flowering of toxic plants and the general validity of honeybee pollination syndrome in the south of Hengduan Mountains in East Asia. A linear relationship between honeybee visitation and plant reproduction can benefit the stabilization of plant reproduction.

Evaluation Of Oat (Avena Sativa L.) Accessions For Fodder Yield And Quality Under Drought Stress

Various aspects of fruit abscission in cotton have been reviewed in the past. Recent advances in this field thus permit consolidation of review of the current research. A major concern among cotton growers is heavy fruit drop, that leads to direct yield loss, which occurs at the expense of squares and young bolls. Shedding of fruiting forms in cotton is the combined consequence of plant itself like hormonal imbalance, plant nutritional status, age relation, and environmental stresses like water deficit, waterlogging, high temperature, dim light, salinity, insects and diseases. These stresses result in prominent signaling modifications like hormonal imbalance. Ethylene is claimed to play a key role in abscission apparently by activating the production of cell wall degrading enzymes such as cellulases and polygalacturonase. The premature dropping of fruiting bodies can significantly increase due to these environmental stresses, which result in severe loss in cotton yield. This article is focused on both internal and external factors that leads to fruit abscission, mechanism of fruit abscission at the physiological, hormonal, and molecular level and trying to point out the missing links on different aspects of plant hormones and environmental stresses regarding fruit abscission. This article also focused on the missing pieces of the very complicated puzzle of fruit abscission process in cotton and elucidation of the mechanism by which plants perceive abscission signals and trigger phytohormone–mediated signal transduction cascades is crucial to devise fruit shedding related breeding and transgenic approaches.

Timing of short‐term drought structures plant–herbivore dynamics

Drought is an important stressor that affects plant growth, survival and physiology and, through plant responses, alters plant–herbivore interactions and herbivore population dynamics. Short‐term drought can occur at different times during a growing season, affecting herbivore populations and plants at various stages of development and growth. As phenology influences drought response, drought timing could strongly structure plant–herbivore interactions. We grew common milkweed plants with or without its dominant aphid herbivore, allowing both plants and herbivore populations to develop over time as in a typical growing season. To determine how drought timing affects plants and aphid populations, we applied short‐term (1 week) drought at different times. Plants and aphids were sensitive to drought timing, with a few weeks difference shifting the effects of drought from minimal to causing massive declines in plant growth, plant survival and herbivore population density. Aphid herbivory added to or overrode drought consequences in plants, with different plant fitness components responding distinctly to herbivory. Drought timing also affected whether plant and herbivore responses were parallel or divergent, suggesting that shifts in the seasonal timing of drought have the potential to disrupt plant–herbivore interactions and affect the larger ecological community. Our results show drought timing has important and disparate consequences for herbivores and their host plants and indicates the necessity of considering phenology and timing in assessing drought response.

Long Short-Term Memory Recurrent Neural Networks for Plant disease Identification

Farming profitability is something on which economy profoundly depends. This is the one reason that sickness recognition in plants assumes a critical job in farming field, as having infection in plants are very common. In the event that legitimate consideration isn't taken here, it causes genuine consequences for plants and because of which particular item quality, amount or profitability is influenced. This paper displays an algorithm for image segmentation technique which is utilized for automatic identification and classification plant leaf infections. It additionally covers review on various classification techniques that can be utilized for plant leaf ailment discovery. As the infected regions vary in length it is difficult to develop a feature vector of identical finite length representing all the sequences. A simple method to go around this issue is given by Recurrent Neural Networks (RNN). In this work we separate a feature vector through the use of Long Short-Term Memory (LSTM) recurrent neural networks. The LSTM network recursively repeats and concentrates two limited vectors whose link yields finite length vector portrayal.

Фітосанітарний стан агроценозу пшениці озимої у Південному Степу України

It is established that winter wheat belongs to the oldest crops and is the main food product in many countries. In Ukraine, the sown area of winter wheat is 5–6 million hectares. More than half of winter wheat grain production falls on the steppe zone. Cereal crops are damaged by insects in all growing zones, especially in the steppe zone of Ukraine. This is due to both the significant diversity of harmful species and the fact that in this area they reproduce most quickly and intensively. In addition, the lack of spring and summer precipitation exacerbates the negative significance of damage. Feeding insects on cereals causes a wide variety of damage, both in nature and in consequences for plants and crops. It is determined that one of the urgent problems of winter wheat protection is the study of patterns of dynamics of the number of major pests in modern agrobiocenoses. According to many scientists, global warming has affected the structure of entomocomplexes, as it optimizes environmental factors for the activities of insects, leads to their reproduction and spread. Harmful entomocomplex of winter wheat covers more than 360 species of insects. They damage the plants of this strategically important crop during all periods of growth. However, the species structure, level of dominance, number and harmfulness of insects are constantly varying, largely due to changes in climatic conditions associated with global warming. The article analyzes the phytosanitary status of winter wheat agrocenoses in the Southern Steppe of Ukraine during 2017–2019. The aim of the study was to determine the species composition and population density of insects in the modern entomocomplex with different technologies of growing crops in short-rotation crop rotations of the Southern Steppe of Ukraine. The research was performed in the research field of the Odessa State Agricultural Research Station of the National Academy of Agrarian Sciences of Ukraine. Observations and records were carried out in all phases of plant development during route inspections of winter wheat fields and adjacent fallows and other stations according to generally accepted methods of entomology and plant protection: mowing with entomological net, shaking of individual plants, test sites and test plants. The species composition of the detected insects was determined in the laboratory. According to the results of studies of the species composition and population density of insects in modern entomocomplexes, it was found that the vast majority of identified species – 78% belong to phytophages, 17% – to entomophages, 5% – to neutral species. Changes in the entomological complex and population levels of the phytophagous complex of the agrocenosis of winter cereals have been revealed. 46 species belonging to 19 families from 8 orders of the insect class were found in the harmful entomofauna. Significant fluctuations of entomocomplex structures in short-rotation crop rotation in the conditions of the Southern Steppe of Ukraine have been established. In particular, with the use of typical zonal technologies for growing crops, which lead to the reproduction of specialized pests.

ZnO nanoparticles induce cell wall remodeling and modify ROS/ RNS signalling in roots of Brassica seedlings

Cell wall-associated defence against zinc oxide nanoparticles (ZnO NPs) as well as nitro-oxidative signalling and its consequences in plants are poorly examined. Therefore, this study compares the effect of chemically synthetized ZnO NPs (~45 nm, 25 or 100 mg/L) on Brassica napus and Brassica juncea seedlings. The effects on root biomass and viability suggest that B. napus is more tolerant to ZnO NP exposure relative to B. juncea. This may be due to the lack of Zn ion accumulation in the roots, which is related to the increase in the amount of lignin, suberin, pectin and in peroxidase activity in the roots of B. napus. TEM results indicate that root cell walls of 25 mg/L ZnO NP-treated B. napus may bind Zn ions. Additionally, callose accumulation possibly contribute to root shortening in both Brassica species as the effect of 100 mg/L ZnO NPs. Further results suggest that in the roots of the relatively sensitive B. juncea the levels of superoxide radical, hydrogen peroxide, hydrogen sulfide, nitric oxide, peroxinitrite and S-nitrosoglutathione increased as the effect of high ZnO NP concentration meaning that ZnO NP intensifies nitro-oxidative signalling. In B. napus; however, reactive oxygen species signalling was intensified, but reactive nitrogen species signalling wasn't activated by ZnO NPs. Collectively, these results indicate that ZnO NPs induce cell wall remodeling which may be associated with ZnO NP tolerance. Furthermore, plant tolerance against ZnO NPs is associated rather with nitrosative signalling than oxidative modifications.

Intraspecific neighbourhood effect: Population‐level consequence of aggregation of highly defended plants

Abstract There is increasing evidence that herbivore–plant interactions on a focal plant species are influenced by interspecific neighbourhood effects via neighbouring plants (i.e. an associational effect). However, intraspecific neighborhood effects imposed by plant traits have been less appreciated. Specifically, the significance of intraspecific neighbourhood effects in population‐level consequences of plants has been totally overlooked. Using two varieties of Nicotiana tabacum (high‐ and low‐nicotine), we evaluated the neighbourhood effects based on patch‐level interactions in a split‐plot 3 × 3 factorial experiment that manipulated number of plants (4, 9 and 16 plants) and culture type (monoculture plots with high‐ and low‐nicotine plants, and polyculture plot) in an experimental garden. We found that herbivore visits on plants varied depending on the number of plants per patch and culture type. Presence of more high‐nicotine plants decreased herbivore visits in the four plant plots, and presence of high‐nicotine plants in the nine plant plots decreased herbivore visits on both high‐ and low‐nicotine plants. In contrast, in the 16 plant plots, herbivore visits on high‐nicotine plants in polyculture plots were lower than others, including those on high‐nicotine plants in monoculture plots. Our findings clearly demonstrated that the intraspecific neighbourhood effect could occur depending on the aggregation of highly defended plants (i.e. high density and/or plant‐spacing). This study suggests that multiple mechanisms for the neighbourhood effect simultaneously worked, depending on the patch size and composition of defensive traits of individual plants, and that intraspecific neighbourhood effects may influence population‐level consequences for plant–herbivore interaction. A free Plain Language Summary can be found within the Supporting Information of this article.

PropaNet: Time-Varying Condition-Specific Transcriptional Network Construction by Network Propagation.

Transcription factor (TF) has a significant influence on the state of a cell by regulating multiple down-stream genes. Thus, experimental and computational biologists have made great efforts to construct TF gene networks for regulatory interactions between TFs and their target genes. Now, an important research question is how to utilize TF networks to investigate the response of a plant to stress at the transcription control level using time-series transcriptome data. In this article, we present a new computational network, PropaNet, to investigate dynamics of TF networks from time-series transcriptome data using two state-of-the-art network analysis techniques, influence maximization and network propagation. PropaNet uses the influence maximization technique to produce a ranked list of TFs, in the order of TF that explains differentially expressed genes (DEGs) better at each time point. Then, a network propagation technique is used to select a group of TFs that explains DEGs best as a whole. For the analysis of Arabidopsis time series datasets from AtGenExpress, we used PlantRegMap as a template TF network and performed PropaNet analysis to investigate transcriptional dynamics of Arabidopsis under cold and heat stress. The time varying TF networks showed that Arabidopsis responded to cold and heat stress quite differently. For cold stress, bHLH and bZIP type TFs were the first responding TFs and the cold signal influenced histone variants, various genes involved in cell architecture, osmosis and restructuring of cells. However, the consequences of plants under heat stress were up-regulation of genes related to accelerating differentiation and starting re-differentiation. In terms of energy metabolism, plants under heat stress show elevated metabolic process and resulting in an exhausted status. We believe that PropaNet will be useful for the construction of condition-specific time-varying TF network for time-series data analysis in response to stress. PropaNet is available at http://biohealth.snu.ac.kr/software/PropaNet.

Changes in timing of seasonal peak photosynthetic activity in northern ecosystems.

Seasonality in photosynthetic activity is a critical component of seasonal carbon, water, and energy cycles in the Earth system. This characteristic is a consequence of plant's adaptive evolutionary processes to a given set of environmental conditions. Changing climate in northern lands (>30°N) alters the state of climatic constraints on plant growth, and therefore, changes in the seasonality and carbon accumulation are anticipated. However, how photosynthetic seasonality evolved to its current state, and what role climatic constraints and their variability played in this process and ultimately in carbon cycle is still poorly understood due to its complexity. Here, we take the "laws of minimum" as a basis and introduce a new framework where the timing (day of year) of peak photosynthetic activity (DOYPmax ) acts as a proxy for plant's adaptive state to climatic constraints on its growth. Our analyses confirm that spatial variations in DOYPmax reflect spatial gradients in climatic constraints as well as seasonal maximum and total productivity. We find a widespread warming-induced advance in DOYPmax (-1.66±0.30days/decade, p<0.001) across northern lands, indicating a spatiotemporal dynamism of climatic constraints to plant growth. We show that the observed changes in DOYPmax are associated with an increase in total gross primary productivity through enhanced carbon assimilation early in the growing season, which leads to an earlier phase shift in land-atmosphere carbon fluxes and an increase in their amplitude. Such changes are expected to continue in the future based on our analysis of earth system model projections. Our study provides a simplified, yet realistic framework based on first principles for the complex mechanisms by which various climatic factors constrain plant growth in northern ecosystems.

UV‐B activates a ‘group A’ mitogen activated protein kinase in Oryza sativa

Increased level of Ultra violet-B radiation at earth’s surface has several deleterious consequences for plants and ecosystems. Higher UV-B level affects crop plants in several ways and also gives penalty in terms of crop yield. With changing climatic conditions it is crucial to elucidate signal transduction pathway involved in UV-B stress. Here, involvement of mitogen activated protein kinases (MAPKs) in UV-B stress was investigated in rice (Oryza sativa). Transcripts profiling of all 15 rice MAPKs have shown UV-B induced expressions of a few MAPK genes including OsMPK3, OsMPK6, OsMPK4, OsMPK17-1, OsMPK17-2, OsMPK20-1, OsMPK20-4 and OsMPK20-5. In-gel kinase assay as well as immuno-kinase assay showed activation of single MAPK of size ~45 kDa in response to UV-B treatment. Further UV-B responsive activity of rice MAPKs, OsMPK3, OsMPK4 and OsMPK6 was checked using antibodies for the respective orthologs in Arabidopsis which indicated activation of OsMPK3 in UV-B stress. Additionally, GST: OsMPK3 protein showed UV responsive phosphorylation when incubated with crude protein extract from UV exposed plants in an in-vitro phosphorylation assay. These results indicate activation of OsMPK3 in UV-B stress. Further, possible involvement of UV-B responsive OsWRKY89 downstream of MAPK cascade was studied. It was observed that staurosporin and other specific chemical inhibitors of MAPK could attenuate UV-B induced expression of OsWRKY89. OsMPK3 was also found to interact with OsWRKY89 in yeast two-hybrid assay, although the interaction was weak in nature. The present work gives an account of MAPKs in UV-B stress in rice.