The intestine is a site of direct encounter with the external environment and must consequently balance barrier defense with nutrient uptake. To investigate how nutrient uptake is regulated in the ...small intestine, we tested the effect of diets with different macronutrient compositions on epithelial gene expression. We found that enzymes and transporters required for carbohydrate digestion and absorption were regulated by carbohydrate availability. The "on-demand" induction of this machinery required γδ T cells, which regulated this program through the suppression of interleukin-22 production by type 3 innate lymphoid cells. Nutrient availability altered the tissue localization and transcriptome of γδ T cells. Additionally, transcriptional responses to diet involved cellular remodeling of the epithelial compartment. Thus, this work identifies a role for γδ T cells in nutrient sensing.
Climate change scenarios forecast increased aridity in large areas worldwide with potentially important effects on nutrient availability and plant growth. Plant nitrogen and phosphorus concentrations ...(plant N and P) have been used to assess nutrient limitation, but a comprehensive understanding of drought stress on plant N and P remains elusive. We conducted a meta‐analysis to examine responses of plant N and P to drought manipulation treatments and duration of drought stress. Drought stress showed negative effects on plant N (−3.73%) and plant P (−9.18%), and a positive effect on plant N : P (+ 6.98%). Drought stress had stronger negative effects on plant N and P in the short term (< 90 d) than in the long term (> 90 d). Drought treatments that included drying–rewetting cycles showed no effect on plant N and P, while constant, prolonged, or intermittent drought stress had a negative effect on plant P. Our results suggest that negative effects on plant N and P are alleviated with extended duration of drought treatments and with drying–rewetting cycles. Availability of water, rather than of N and P, may be the main driver for reduced plant growth with increased long‐term drought stress.
Main conclusion
Nutrient transporter genes could be a potential candidate for improving crop plants, with enhanced nutrient uptake leading to increased crop yield by providing tolerance against ...different biotic and abiotic stresses.
The world’s food supply is nearing a crisis in meeting the demands of an ever-growing global population, and an increase in both yield and nutrient value of major crops is vitally necessary to meet the increased population demand. Nutrients play an important role in plant metabolism as well as growth and development, and nutrient deficiency results in retarded plant growth and leads to reduced crop yield. A variety of cellular processes govern crop plant nutrient absorption from the soil. Among these, nutrient membrane transporters play an important role in the acquisition of nutrients from soil and transport of these nutrients to their target sites. In addition, as excess nutrient delivery has toxic effects on plant growth, these membrane transporters also play a significant role in the removal of excess nutrients in the crop plant. The key function provided by membrane transporters is the ability to supply the crop plant with an adequate level of tolerance against environmental stresses, such as soil acidity, alkalinity, salinity, drought, and pathogen attack. Membrane transporter genes have been utilized for the improvement of crop plants, with enhanced nutrient uptake leading to increased crop yield by providing tolerance against different biotic and abiotic stresses. Further understanding of the basic mechanisms of nutrient transport in crop plants could facilitate the advanced design of engineered plant crops to achieve increased yield and improve nutrient quality through the use of genetic technologies as well as molecular breeding. This review is focused on nutrient toxicity and tolerance mechanisms in crop plants to aid in understanding and addressing the anticipated global food demand.
Water balance influences soil development, and consequently plant communities, by driving weathering of soil minerals and leaching of plant nutrients from the soil. Along gradients in water balance, ...soils exhibit process domains where chemical properties are relatively stable punctuated by pedogenic thresholds where soil chemical properties change rapidly with little additional change in water balance. We ask if plant macronutrient concentrations in leaves also exhibit non-linear trends along water balance gradients, and if so, how these non-linearities relate to those in soils. We analyze foliar nutrient concentrations and foliar N:P ratios from eight species that span a range of growth forms along three water balance gradients (three of the species are found on multiple gradients). The gradients are located on basaltic substrate of different ages and have previously been characterized by studies on soil development. We find that maximum concentrations of foliar macronutrients occur at an intermediate water balance. As with soil nutrients, time mediates the effect of water balance on foliar nutrients, such that plants on older soils attain maximum nutrient concentrations at a lower water balance. On both a young, 20 ky and an old, 4100 ky water balance gradient, foliar nutrients reach peak concentrations at a water balance greater than the threshold for depletion of rock-derived nutrients in surface soils. Our findings suggest that plant acquisition of essential nutrients is imperfectly predicted by overall soil nutrient availability because the regulation of internal nutrient pools by plants makes nutrient pools within leaves partially independent of soil nutrient availability.
While grazing exclusion is thought to drive soil nutrient transport and cycling, and reduce soil compaction, its direct impact on microbial community composition remains unclear. In this study, we ...examined the impact of grazing exclusion on abundance and composition of soil microbial (bacterial, archaeal, and fungal) communities, especially those associated with nutrient cycling. We surveyed soil physicochemical properties and litter mass, at sites undergoing varying durations of grazing exclusion (0–34 years) in a semiarid grassland. Using next-generation amplicon sequencing, we further characterized variations in the composition and diversity of soil microbial communities associated with grazing exclusion and soil depths, as well as subsequent changes in physicochemical properties. Most soil physicochemical parameter values significantly increased as the result of long-term grazing exclusion, and these properties were associated with variation in composition and diversity of microbial communities. Notably, the relative abundances of microbial families associated with C cycling (e.g.,
Chitinophagaceae
) increased with an increase in nutrient availability following grazing exclusion. The abundance of the archaeal ammonia-oxidizing
Nitrososphaerae
increased with decreasing concentration of ammonium among samples. Likewise, fungal communities were also associated with the shifts in nutrient concentrations, although the majority of fungi could not be classified to the species level. Nitrate concentration also played a critical role in shaping bacterial, archaeal, or fungal communities. Moreover, bacterial and archaeal communities had a greater mean Shannon index in 0–10-cm than those in 10–20-cm soil layer. Results of this study provide novel insights regarding how the length of grazing exclusion and soil depth influence nutrient gradients and microbial community composition associated with nutrient cycling.
BACKGROUND AND AIMS: Arbuscular mycorrhizas (AM) enhance plant uptake of a range of mineral nutrients from the soil. Interactions between nutrients in the soil and plant, are complex, and can be ...affected by AM. Using a mycorrhiza-defective mutant tomato genotype (rmc) and its wild-type (76R), provides a novel method to study AM functioning. METHODS: We present a meta-analysis comparing tissue nutrient concentration (P, Zn, K, Ca, Cu, Mg, Mn, S, B, Na, Fe), biomass and mycorrhizal colonisation data between the 76R and rmc genotypes, across a number of studies that have used this pair of tomato genotypes. Particular attention is paid to interactions between soil P or soil Zn, with tissue nutrients. RESULTS: For most nutrients, the difference in concentration between genotypes was significantly affected either by soil P, soil Zn, or both. When soil P was deficient, AM were particularly beneficial in terms of uptake of not only P, but other nutrients as well. CONCLUSIONS: Colonisation by AMF significantly affects the uptake of many soil macro- and micro-nutrients. Furthermore, the soil P and Zn status also influences the difference in nutrient concentrations between mycorrhizal and non-mycorrhizal plants. The interactions identified by this meta-analysis provide a basis for future research in this area.
The winner population forms a stable, swarming community (filled cells on top) while the loosing species (non-filled cells, near the starting position) will form a small community that will either ...stagnate in the solitary state, or die out, depending on the nutrients available. In the dfferent patches, either one or the other species is nearer to the resources. https://doi.org/10.1371/journal.pone.0057947.g001 thumbnail Download: * PPT PowerPoint slide * PNG larger image * TIFF original image Figure 4.
Biological nitrogen (N) fixation (BNF), an important source of N in terrestrial ecosystems, plays a critical role in terrestrial nutrient cycling and net primary productivity. Currently, large ...uncertainty exists regarding how nutrient availability regulates terrestrial BNF and the drivers responsible for this process. We conducted a global meta‐analysis of terrestrial BNF in response to N, phosphorus (P), and micronutrient (Micro) addition across different biomes (i.e, tropical/subtropical forest, savanna, temperate forest, grassland, boreal forest, and tundra) and explored whether the BNF responses were affected by fertilization regimes (nutrient‐addition rates, duration, and total load) and environmental factors (mean annual temperature MAT, mean annual precipitation MAP, and N deposition). The results showed that N addition inhibited terrestrial BNF (by 19.0% (95% confidence interval CI: 17.7%‒20.3%); hereafter), Micro addition stimulated terrestrial BNF (30.4% 25.7%‒35.3%), and P addition had an inconsistent effect on terrestrial BNF, i.e., inhibiting free‐living N fixation (7.5% 4.4%‒10.6%) and stimulating symbiotic N fixation (85.5% 25.8%‒158.7%). Furthermore, the response ratios (i.e., effect sizes) of BNF to nutrient addition were smaller in low‐latitude (<30°) biomes (8.5%‒36.9%) than in mid‐/high‐latitude (≥30°) biomes (32.9%‒61.3%), and the sensitivity (defined as the absolute value of response ratios) of BNF to nutrients in mid‐/high‐latitude biomes decreased with decreasing latitude (p ≤ 0.009; linear/logarithmic regression models). Fertilization regimes did not affect this phenomenon (p > 0.05), but environmental factors did affect it (p < 0.001) because MAT, MAP, and N deposition accounted for 5%‒14%, 10%‒32%, and 7%‒18% of the variance in the BNF response ratios in cold (MAT < 15°C), low‐rainfall (MAP < 2,500 mm), and low‐N‐deposition (<7 kg ha−1 year−1) biomes, respectively. Overall, our meta‐analysis depicts a global pattern of nutrient impacts on terrestrial BNF and indicates that certain types of global change (i.e., warming, elevated precipitation and N deposition) may reduce the sensitivity of BNF in response to nutrient enrichment in mid‐/high‐latitude biomes.
This study addresses how nutrient addition regulates biological nitrogen (N) fixation (BNF) in terrestrial ecosystems and uncovers the latitude patterns and drivers of BNF in response to nutrient enrichment. We found a negative effect of N addition, a positive effect of Micro addition, and an inconsistent effect of P addition on terrestrial BNF and also observed a less sensitivity of BNF to nutrient addition in low‐latitude biomes than in mid‐/high‐latitude biomes. Our findings indicate that certain types of global change (warming, elevated precipitation and N deposition) may reduce the nutrient constraints of BNF in mid‐/high‐latitude biomes.
Summary
Warming‐induced desiccation of the fertile topsoil layer could lead to decreased nutrient diffusion, mobility, mineralization and uptake by roots. Increased vertical decoupling between ...nutrients in topsoil and water availability in subsoil/bedrock layers under warming could thereby reduce cumulative nutrient uptake over the growing season.
We used a Mediterranean semiarid shrubland as model system to assess the impacts of warming‐induced topsoil desiccation on plant water‐ and nutrient‐use patterns. A 6 yr manipulative field experiment examined the effects of warming (2.5°C), rainfall reduction (30%) and their combination on soil resource utilization by Helianthemum squamatum shrubs.
A drier fertile topsoil (‘growth pool’) under warming led to greater proportional utilization of water from deeper, wetter, but less fertile subsoil/bedrock layers (‘maintenance pool’) by plants. This was linked to decreased cumulative nutrient uptake, increased nonstomatal (nutritional) limitation of photosynthesis and reduced water‐use efficiency, above‐ground biomass growth and drought survival.
Whereas a shift to greater utilization of water stored in deep subsoil/bedrock may buffer the negative impact of warming‐induced topsoil desiccation on transpiration, this plastic response cannot compensate for the associated reduction in cumulative nutrient uptake and carbon assimilation, which may compromise the capacity of plants to adjust to a warmer and drier climate.
Plants in infertile habitats are thought to have a high rate of nutrient resorption to enable them reuse nutrients more efficiently than those in fertile habitats. However, there is still much debate ...on how plant nutrient resorption responds to nutrient availability. Here we used a meta-analysis from a global data set of 9703 observations at 306 sites from 508 published articles to examine the effects of nitrogen (N) and phosphorus (P) fertilization on plant foliar N and P concentrations and resorption efficiency. We found that N fertilization enhanced N concentration in green leaves by 27% and P fertilization enhanced green-leaf P by 73% on average. The N and P concentrations in senesced leaves also increased with respective nutrient fertilization. Resorption efficiencies (percentage of nutrient recovered from senescing leaves) of both N and P declined in response to respective nutrient fertilization. Combined N and P fertilization also had negative effects on both N and P resorption efficiencies. Whether nutrient resorption efficiency differs among plant growth types and among ecosystems, however, remains uncertain due to the limited sample sizes when analyzed by plant growth types or ecosystem types. Our analysis indicates that fertilization decreases plant nutrient resorption and the view that nutrient resorption is a critical nutrient conservation strategy for plants in nutrient-poor environments cannot be abandoned. The response values to fertilization presented in our analysis can help improve biogeochemical models.
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