Bioenergy Crops Research Articles

Four sugarcane ScDIR genes contribute to lignin biosynthesis and disease resistance to Sporisorium scitamineum

Sugarcane (Saccharum spp.) is a major sucrose and bioenergy crop in the world. The fungal pathogen Sporisorium scitamineum causes sugarcane smut, a devastating disease that destroys stalks and reduces sugar content in sugarcane. This disease can be controlled most effectively by applying smut-resistant sugarcane varieties. Previous studies have shown that Dirigent (DIR) genes are involved in the synthesis of the lignin precursor pinoresinol, which plays a crucial role in plant resistance to biotic stresses. However, the immune response of the DIR homologs in sugarcane (ScDIR) has not been reported yet. In this study, we found that the lignin content of smut-resistant sugarcane varieties (ZZ1, ZZ6, and ZZ9) was significantly higher than that of smut-susceptible varieties (GT42, ROC22, and FN41), and the lignin content of sugarcane increased after smut infection. The smut-resistant and smut-susceptible clones derived from the same genetic population (ROC25 × YZ89-7) showed similar patterns. Quantitative real-time PCR assays revealed that among the 64 DIR genes in sugarcane, ScDIR5, ScDIR7, ScDIR11, and ScDIR40 showed elevated expression after S. scitamineum infection. In vitro coupling reactions showed that the four corresponding ScDIR proteins could mediate the coupling of coniferyl alcohol and its conversion into the lignin precursor pinoresinol. Overexpression of the four ScDIR genes in Nicotiana benthamiana enhanced disease resistance to the fungal pathogens Sclerotium rolfsii, Rhizoctonia solani, and Botrytis cinerea. Moreover, transgenic sugarcane overexpressing these ScDIR genes showed enhanced resistance to smut disease. Taken together, our findings provide evidence that sugarcane ScDIR genes can improve the resistance of plants to fungal pathogens and highlight their potentials in sugarcane breeding for disease resistance.

Modeling net ecosystem exchange of CO2 with gated recurrent unit neural networks

The complex forcing mechanisms of biophysical drivers on ecosystem productivity, as well as some unknown relationships, stipulates the application of artificial intelligence techniques in modeling the ecosystem carbon cycle. In particular, various deep learning algorithms have been successfully applied to comprehend temporal relationships, though some issues regarding capturing temporal features for modeling CO2 fluxes across time scales remain unsolved. In this study, a gated recurrent unit (GRU) model was trained for simulating half-hourly net ecosystem exchange of CO2 (NEE) using 12-year continuous flux data (2009–2020) from seven experimental bioenergy crops in southwest Michigan, USA. The fields were historically managed either as corn-soybean rotation agricultural (AGR) or Conservation Reserve Program (CRP) lands and planted to no-till corn (AGR-C and CRP-C), restored-prairie (AGR-Pr and CPR-Pr), switchgrass (AGR-Sw and CRP-Sw) and smooth brome grass (CRP-Ref). We compared NEE simulations for the entire year, growing season, and non-growing season datasets, and analyzed relative importance of biophysical variables on variations of NEE. GRU performed well in simulating NEE at single site, with R2 of 0.89–0.93, 0.85–0.90, and 0.61–0.85 for the annual, growing season, and non-growing season datasets, respectively, which provided comparable accuracy and 6 % of run-time shorter than those of long short-term memory. R2 reached 0.70 and 0.80 across all sites and unique land-cover types. Radiation parameters contributed most to the variability of NEE. Contributions of individual variables appear more complex during the non-growing season and include incoming shortwave radiation, day of year, temperature, Monin-Obukhov stability, wind direction, and soil water content. The six most important forcing variables are consistent with our current understanding, although their ranked importance varied by ecosystem type and modeling scale. These results bring renewed insights in modeling observations at seasonal scales and provide guidance for variable selection to scale up measurements from one site to multiple land-cover types across the landscape.

Efficiency of weed control in winter pea in the Right Bank Forest Steppe of Ukraine

Purpose. To analyze the features of weed control in winter pea in the Right Bank Forest Steppe of Ukraine. Methods. The research was conducted at the Salyvonky State Enterprise of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Agrarian Sciences of Ukraine (Bila Tserkva district, Kyiv region) in 2020–2023. The agronomic practices used in the experiment were conventional for the zone of insufficient moisture of the Right Bank Forest Steppe of Ukraine, with the exception of the studied elements. Results. The development of the concept of autumn weed control for winter pea from requires a fairly competent selection of herbicides, taking into account weather forecasts, the specifics of the effect of active substances on weeds and cultivated plants, etc., as conditions for sowing winter pea do not allow to effectively apply conventional weed control system with the use of soil tillage and, if necessary, the limited application of herbicides during the vegetation season. This is explained by the fact that the terms for soil preparation and sowing are quite limited, and soil herbicides at high air temperatures work unpredictably and have limited efficiency in case of moisture deficit. Herbicide Corum, developed by combination of active substances bentazone (480 g/l) and imazomox (22 g/l), had better indicators in terms of total efficiency at an increased application rate (1.5 l/ha) – 92.9% in the BBCH 12 and 91.7% in the BBCH 14. At the same time, the efficiency of an application rate of 1.25 l/ha was within 80%. The latter is probably related not only to the autumn conditions of application of the [reparation, but also to the fact that such species as Fumaria officinalis, Sinapis arvensis, Solanum nigrum and thistles sprouted later, when the main mass of weeds was already in a development stage that was less sensitive to low rates of the herbicide. Conclusions. The application of Corum herbicide in the BBCH 12 at an application rate of 1.25 l/ha contributed to the destruction of 73.8% and an application rate of 1.5 l/ha resulted in 86.7% of weeds. When the herbicide was applied in BBCH 14, the total efficiency of crop treatment at an application rate of 1.25 l/ha was higher by 2.4% and at a rate of 1.5 l/ha it was higher by 1.2% compared to application in the BBCH 12. This is due to the fact that Chenopodium album, Amaranthus retroflexus, Polygonum convolvulus, Persicaria maculosa, Solanum nigrum, Polygonum lapathifolium and thistles sprouted in the pea crops, and the herbicide was highly effective against them. On the other hand, weed plants that sprouted earlier continued to vegetate and were already less sensitive even to increased application rates of herbicide. The application of the maximum recommended application rates was, for the most part, the most effective measure to reduce the number of weeds in winter pea crops. At the same time, such rates affected crop plants, causing stress, especially in the late periods of growth and development, which further affected the formation of pea yield. Therefore, the use of herbicides in the late phases of crop development should be avoided.

Engineered poplar for bioproduction of the triterpene squalene.

Building sustainable platforms to produce biofuels and specialty chemicals has become an increasingly important strategy to supplement and replace fossil fuels and petrochemical-derived products. Terpenoids are the most diverse class of natural products that have many commercial roles as specialty chemicals. Poplar is a fast growing, biomassdense bioenergy crop with many species known to produce large amounts of the hemiterpene isoprene, suggesting an inherent capacity to produce significant quantities of other terpenes. Here we aimed to engineer poplar with optimized pathways to produce squalene, a triterpene commonly used in cosmetic oils, a potential biofuel candidate, and the precursor to the further diversified classes of triterpenoids and sterols. The squalene production pathways were either re-targeted from the cytosol to plastids or co-produced with lipid droplets in the cytosol. Squalene and lipid droplet co-production appeared to be toxic, which we hypothesize to be due to disruption of adventitious root formation, suggesting a need for tissue specific production. Plastidial squalene production enabled up to 0.63 mg/g fresh weight in leaf tissue, which also resulted in reductions in isoprene emission and photosynthesis. These results were also studied through a technoeconomic analysis, providing further insight into developing poplar as a production host.

Sustainable co-production of plant lipids and cellulosic sugars from transgenic energycane at an industrially relevant scale: A proof of concept for alternative feedstocks

Development of sustainable and scalable technologies to convert lignocellulosic biomass to biofuels is critical to achieving carbon neutrality. The potential of transgenic bioenergy crops as a renewable source of sugars and lipids has been demonstrated at bench-scale. However, scaling up these processes is important for holistic analysis. Here proof-of-concept for chemical-free hydrothermal pretreatment of transgenic energycane-oilcane line L13 at an industrially relevant scale to recover vegetative lipids along with cellulosic sugars is presented. Pilot-scale processing of 97 kg of transgenic energycane-oilcane L13 stems and high solids pretreatment of bagasse enhanced the recovery of cellulosic glucose and xylose by 5-fold as compared to untreated bagasse and helped in the enrichment of vegetative lipids in the biomass residues which allowed its recovery at the end of the bioprocess. Palmitic and oleic acids were the predominant fatty acids (FAs) extracted from stems and leaves. The processing did not affect lipid composition. The efficiency of lipid recovery from untreated biomass was 75.9% which improved to 88.7% upon pretreatment. The vegetative tissues of transgenic energycane-oilcane L13 contained 0.42 metric tons/hectare of lipids. Processing vegetative tissues yielded 0.38 metric tons/hectare of lipids. This approaches an oil yield similar to soybean (global average 0.44 metric tons/hectare) and is almost twice as high as the oil yield from sugarcane engineered to hyperaccumulate lipids (0.20 metric tons/hectare). The study suggests that further optimization by state-of-the-art metabolic engineering and biomass processing can establish transgenic bioenergy crops for commercial drop-in fuel production.

Early production of switchgrass (Panicum virgatum L.) and willow (Salix spp.) indicates carbon accumulation potential in Appalachian reclaimed mine and agriculture soil

AbstractThe production of bioproduct feedstocks such as switchgrass (Panicum virgatum L.) and willow (Salix spp.) on degraded lands provides an opportunity to grow dedicated bioenergy crops with the potential to capture and store carbon in the soil while reducing competition with land for food production. However, how the production of these crops alters plant–soil–microbe interactions that govern soil C accumulation in highly degraded soil is underexplored. The objectives of this study were to examine select biological and chemical properties related to stable soil organic matter (SOM) production from the growth of switchgrass and willow on marginal soil over two growing seasons and whether biochar amendment can positively affect these parameters. To address our objectives, paired former surface mined lands and non‐mine impacted marginal agriculture sites were selected across West Virginia, USA, and biochar and unamended control treatments were imposed. Through the first two growing seasons, microbial activity and demand for carbon (C) increased and was accompanied by a shift in extracellular enzyme investment for decomposition‐associated enzymes. Mineral‐associated organic matter C increased over the two growing seasons, and this increase was greater in the mine sites compared to the agriculture sites. Compared to each site's previous land use, C losses were observed under bioproduct systems in the agriculture, but not the mine sites. Biochar amendments did not impact microbial activity but did increase the C:N of SOM. Overall, our results suggest that the early growth of switchgrass and willow can result in C accumulation in marginal and highly degraded lands.

Bioenergy in Europe is unlikely to make a timely contribution to climate change targets

Increasing bioenergy production is a significant component of European efforts to mitigate climate change, but has contested potential for reducing emissions. We use an integrated land system model to explore the effects of large-scale bioenergy production within the European Union on carbon balances. We find that increased bioenergy crop production is likely to cause substantial deforestation and a commensurate loss of associated carbon stocks largely due to displacement of food production from other areas. Deforestation would occur either within the EU if European forests were not protected, or in other parts of the world arising from indirect land use change if European forests were protected. The net carbon benefit of bioenergy production is largely negative, or uncertain, even under the most optimistic levels of fossil fuel replacement, and will not offset initial carbon losses over the coming 50 yr. The growth of intensive agriculture required to satisfy the demand for bioenergy and food will have negative impacts on crucial ecosystem services. Overall, we identify substantial disadvantages to increasing bioenergy production relative to freeing land for natural succession. At best, large-scale bioenergy production is likely to be irrelevant to time-sensitive climate targets.

Genome-wide identification of WRKY transcription factor family members in Miscanthus sinensis (Miscanthus sinensis Anderss)

Miscanthus is an emerging sustainable bioenergy crop whose growing environment is subject to many abiotic and biological stresses. WRKY transcription factors play an important role in stress response and growth of biotic and abiotic. To clarify the distribution and expression of the WRKY genes in Miscanthus, it is necessary to classify and phylogenetically analyze the WRKY genes in Miscanthus. The v7.1 genome assembly of Miscanthus was analyzed by constructing an evolutionary tree. In Miscanthus, there are 179 WRKY genes were identified. The 179 MsWRKYs were classified into three groups with conserved gene structure and motif composition. The tissue expression profile of the WRKY genes showed that MsWRKY genes played an essential role in all growth stages of plants. At the early stage of plant development, the MsWRKY gene is mainly expressed in the rhizome of plants. In the middle stage, it is mainly expressed in the leaf. At the end stage, mainly in the stem. According to the results, it showed significant differences in the expression of the MsWRKY in different stages of Miscanthus sinensis. The results of the study contribute to a better understanding of the role of the MsWRKY gene in the growth and development of Miscanthus.

The Quantitative Inhibition Effects of Meteorological Drought on Sugarcane Growth Using the Decision Support System for Agrotechnology Transfer-CANEGRO Model in Lai-bin, China

Sugarcane is the most important cash crop for producing sugar and the most promising high-yield bioenergy crop in China. Lai-bin is a major sugarcane growing and karst area in the Guangxi Province of China. However, frequent droughts over the years have caused huge losses on sugarcane production in this region. Therefore, the daily quantitative response mechanisms of sugarcane growth to multiple meteorological drought scenarios were discovered in Lai-bin using the DSSAT−CANEGRO model. The daily Standardized Precipitation Evapotranspiration Index (SPEI) was developed to detect the possible scenarios of meteorological drought events over the sugarcane growth periods. The results indicate that, in general, the inhibitory effect on sugarcane growth is enhanced by the increase in the intensity and duration of meteorological drought, which involved cane yield (CY), stem height (SH), leaf area index (LAI), and evapotranspiration (ET). Additionally, a light drought at the seedling stage and a light, moderate, and severe drought at the maturity stage give a promotion effect on sugarcane growth, but its overall CY increase rate is less than 5%. The stem elongation stage is the most sensitive period of sugarcane growth to all scenarios of meteorological drought, and the CY reduction rates reached 7.12%, 16.48%, 18.80%, and 29.05%, when the plants suffered from light, moderate, severe, and extreme meteorological droughts, respectively. Alternate drought–flood scenarios presented a facilitating or an inhibiting effect on sugarcane growth during different periods, which cannot be ignored. In conclusion, the quantitative function relationships between meteorological drought and sugarcane growth are revealed by this study.

Bridging Quantitative and Qualitative Science for BECCS in Abandoned Croplands

AbstractBioenergy with carbon capture and storage (BECCS) plays a vital role in most climate change mitigation scenarios, where a solution for sustainable near‐term bioenergy expansion is to grow energy crops such as perennial grasses on recently abandoned cropland. There is a need to combine model‐based insights into theoretical potential and future biomass supply with more fine‐grained sociotechnical analysis to move toward realistic policies and innovation strategies. We combine natural science insights anchored in quantitative bioenergy modeling with qualitative social science anchored in the multi‐level perspective. Using these mixed methods enables a global‐to‐local‐to‐global level assessment of near‐term bioenergy recultivation opportunities for abandoned cropland. Norway is the local case. There are three main findings. First, the ongoing recultivation trends for food/feed production risks making gains in aboveground carbon stocks from natural regrowth on the mapped abandoned cropland over a 30‐year evaluation period almost negligible. Second, delaying a BECCS recultivation of abandoned cropland will make it impossible to reach high‐end mitigation potentials, and an accelerated BECCS recultivation guided by a policy push is needed to ensure stronger mitigation. Third, we unravel several real‐world challenges associated with bioenergy resource and supply modeling. Remote‐sensing techniques alone cannot capture actual land availability for land‐based climate change mitigation strategies. Local‐level sociotechnical conditions are generally found insufficiently supportive to align with the rapid near‐term bioenergy crop expansion found in 2°C scenarios from integrated assessment. The integration of mixed quantitative and qualitative methods is key to better understand the role of BECCS in climate change mitigation.

Bioenergy and sustainable agriculture: A review of synergies and potential conflicts

The intersection of bioenergy and sustainable agriculture presents a dynamic landscape with both promising synergies and potential conflicts that demand careful consideration. This comprehensive review explores the intricate relationship between bioenergy production and sustainable agricultural practices, aiming to elucidate the opportunities and challenges inherent in their integration. Synergies between bioenergy and sustainable agriculture are evident in their shared goal of mitigating climate change. Bioenergy crops, such as perennial grasses and woody biomass, can sequester carbon and contribute to greenhouse gas reduction, aligning with the principles of sustainable agriculture that emphasize environmental stewardship. Additionally, the integration of bioenergy systems with agricultural practices can foster resource efficiency, as crop residues and organic waste become valuable feedstocks for biofuel production. However, potential conflicts arise when land-use competition intensifies. The expansion of bioenergy crops may encroach upon land designated for food production, leading to concerns about food security and biodiversity loss. Striking a balance requires careful planning, considering regional variations in land availability, climate, and socio-economic factors. Furthermore, the review delves into the technological advancements driving the coexistence of bioenergy and sustainable agriculture. Precision farming techniques, agroforestry, and innovative cropping systems emerge as tools to optimize land use, enhance resource efficiency, and minimize environmental impacts. In conclusion, the intertwining realms of bioenergy and sustainable agriculture offer a complex tapestry of synergies and potential conflicts. A nuanced and context-specific approach is essential for maximizing the benefits while minimizing adverse impacts. This review provides insights into the current state of knowledge, highlighting the need for interdisciplinary collaboration, policy frameworks, and technological innovations to ensure a harmonious coexistence between bioenergy production and sustainable agriculture.

Social Capital, Trust, and Cultivation of Bioenergy Crops: Evidence from Germany and Greece

In the move towards bioeconomy, little is known about the contribution of factors such as social capital and trust in farmers’ motivation for adopting innovative practices like the cultivation of drought-tolerant bioenergy crops. Based on the broad notion of social capital, this research investigates the level of trust in institutions, cooperation, and the cultural value of farming in Greece and in Germany. Focus group discussions and interviews with farmers show similar levels of trust in institutions in both countries. Trust in cooperation positively related to community social cohesion in Germany, in contrast to the predominant mistrust of formal and informal forms of cooperation in Greece. In Germany, the cultural value of farming, urban “demands” impeding traditional small-scale farming, and their primary role in producing and guarding the rural environment tend to hinder the adoption of bioenergy crop cultivations. In Greece, the marginalization of farming results in an uncertain/ambiguous farming self-concept and, in turn, to an easier adoption of innovations such as the cultivation of bioenergy crops. All three dimensions are pivotal in agriculture, rural development, and energy transition, as they affect how people relate to institutions and to each other and organize and perceive themselves in the current representations of rurality.

PvARL1 Increases Biomass Yield and Enhances Alkaline Tolerance in Switchgrass (Panicum virgatum L.).

Switchgrass is an important bioenergy crop valued for its biomass yield and abiotic tolerance. Alkali stress is a major abiotic stress that significantly impedes plant growth and yield due to high salinity and pH; however, the response mechanism of switchgrass to alkali stress remains limited. Here, we characterized PvARL1, an ARF-like gene, which was up-regulated in both the shoot and root tissues under alkali stress conditions. Overexpression of PvARL1 not only improved alkali tolerance but also promoted biomass yield with more tiller and higher plant height in switchgrass. Moreover, PvARL1 overexpression lines displayed higher capacities in the maintenance of water content and photosynthetic stability compared with the controls under alkali treatments. A significant reduction in the ratio of electrolyte leakage, MDA content, and reactive oxygen species (ROS) showed that PvARL1 plays a positive role in protecting cell membrane integrity. In addition, PvARL1 also negatively affected the K+ efflux or uptake in roots to alleviate ion toxicity under alkali treatments. Overall, our results suggest that PvARL1 functions as a positive regulator in plant growth as well as in the plant response to alkali stress, which could be used to improve switchgrass biomass yield and alkali tolerance genetically.

Phenological coding of Crambe abyssinica Hochst. according to the BBCH system

AbstractCrambe (Crambe abyssinica Hochst.) is an oilseed crop domesticated in the Mediterranean region that is becoming increasingly important worldwide. Crambe is now considered as an alternative to bioenergy crops and oleochemicals, because of its ability to acclimatise under inhospitable conditions. Despite the interest in the agronomic characteristics and applications of this crop, research on crambe is still scarce and has focused only on production, taking into account the phenological stages of this species. Therefore, a single criterion for quantifying the phenology of the species can be a useful tool for both researchers and growers. In the present study, a proposed scale of the phenological growth stages of crambe was applied according to the BBCH (Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie) coding system. The phenological stages were described using the one‐ and two‐digit decimal coding of the BBCH system and corresponded to stage 0: germination; stage 1: leaf development; stage 2: lateral sprout formation; stage 5: inflorescence emergence; stage 6: flowering; stage 8: fruit ripening and stage 9: senescence. Growth stages 3 and 4 (main stem elongation and development of collectable vegetative parts, respectively) have been omitted. Figures have been included to illustrate the main stages, and plant growth has been represented by a technical botanical illustration. The BBCH system has been effective in providing phenological data on crambe, allowing for better growing management of the crop under varying climatic conditions, as well as contributing to the standardisation of research methods on the species.

Dispersal and persistence of cup plant seeds (Silphium perfoliatum): do they contribute to potential invasiveness?

Background and aims – The cup plant (Silphium perfoliatum) is being grown in Germany as a promising new bioenergy crop with an increasing area under cultivation in the last years. Its alien status, its high productivity, and high reproductive potential could carry the risk of this species becoming invasive. The present study investigates the dispersal and persistence of cup plant seeds, to contribute to the assessment of its invasive potential. Material and methods – For this purpose, four experimental studies were conducted in Germany, Central Europe: wind dispersal distance was measured in a field experiment for wind speeds up to 7 m.s-1. The seeds were offered to rodents in different habitats near to a cup plant field. We observed seed persistence and germination over 4 weeks storing in water and over 4 years storing in different soil depths. Key results – Cup plant seeds are dispersed by wind only over a few meters. In the forest, rodents removed 100% of the offered seeds, in open habitats none. Independent of the duration of storage in water, germination rate of the cup plant seeds was constantly high. Most of the seeds already germinated in water in the first two weeks. Stored on the soil surface and at 10 cm soil depth, the seeds germinated already in the first two years. Stored at 30 cm depth, one third of the seeds retained their germination ability over four years. Conclusion – Wind serves as short-distance dispersal vector for cup plant seeds. Rodents remove the seeds, but it is unknown whether they disperse them or just eat them. Water could disperse the seeds, which retain their germination ability, over long distances. The cup plant could therefore spread and possibly become invasive in Central Europe, and therefore measures are suggested to prevent its dispersal and spontaneous settlement.

The role of sudden variance shifts in predicting volatility in bioenergy crop markets under structural breaks

Forecasting bioenergy feedstock commodity volatility has received significant attention due to its importance in biofuel production and household consumption. Several extreme events, including the COVID-19 pandemic, have sparked interest in studying the role of structural breaks on volatility modeling and prediction in these markets. This study extensively examines the prediction performance of econometric models at multiple horizons using a rolling-window approach, with and without accommodating structural changes. We exploit the ICSS algorithm to determine the in-sample estimation windows to accommodate structural breaks. We extend the procedure beyond GARCH-class models. Also, the detected break information defines the regime dummies. The study innovatively evaluates the prediction performance of specific GARCH-class models by incorporating binary variables for sudden shifts in unconditional variance. Our findings reveal that accounting for the endogenously detected structural breaks through the dummy variables leads to considerable forecast accuracy gains.

IbNIEL-mediated degradation of IbNAC087 regulates jasmonic acid-dependent salt and drought tolerance in sweet potato.

Sweet potato (Ipomoea batatas [L.] Lam.) is a crucial staple and bioenergy crop. Its abiotic stress tolerance holds significant importance in fully utilizing marginal lands. Transcriptional processes regulate abiotic stress responses, yet the molecular regulatory mechanisms in sweet potato remain unclear. In this study, a NAC (NAM, ATAF1/2, and CUC2) transcription factor, IbNAC087, was identified, which is commonly upregulated in salt- and drought-tolerant germplasms. Overexpression of IbNAC087 increased salt and drought tolerance by increasing jasmonic acid (JA) accumulation and activating reactive oxygen species (ROS) scavenging, whereas silencing this gene resulted in opposite phenotypes. JA-rich IbNAC087-OE (overexpression) plants exhibited more stomatal closure than wild-type (WT) and IbNAC087-Ri plants under NaCl, polyethylene glycol, and methyl jasmonate treatments. IbNAC087 functions as a nuclear transcriptional activator and directly activates the expression of the key JA biosynthesis-related genes lipoxygenase (IbLOX) and allene oxide synthase (IbAOS). Moreover, IbNAC087 physically interacted with a RING-type E3 ubiquitin ligase NAC087-INTERACTING E3 LIGASE (IbNIEL), negatively regulating salt and drought tolerance in sweet potato. IbNIEL ubiquitinated IbNAC087 to promote 26S proteasome degradation, which weakened its activation on IbLOX and IbAOS. The findings provide insights into the mechanism underlying the IbNIEL-IbNAC087 module regulation of JA-dependent salt and drought response in sweet potato and provide candidate genes for improving abiotic stress tolerance in crops.

Biomass partitioning reveals the adaptability of tiger nut (Cyperus esculentus L.) in an arid ecosystem in Inner Mongolia, China

AbstractTiger nuts (Cyperus esculentus L.) have been widely cultivated as a bioenergy crop in northern China. The value of tubers is receiving special attention, but the lack of information on how organs of tiger nuts coordinate resources to adapt to arid environments has limited the potential tuber production and diverse use. To address this knowledge gap, we experimented in the Ulan Buh Desert, Inner Mongolia (106° 33′ 28″ E, 40° 27′ 32″ N). Three fertilizer treatments were applied: zero fertilizer (N:P = 0:0), traditional fertilizer (N:P = 15:15), and additional nitrogen fertilizer (N:P = 60:15). Investigations were conducted at seedling, rhizome production, tuber formation, and tuber maturation stages. The results showed that under zero fertilizer, tiger nuts allocated biomass predominantly to propagative organs, namely rhizomes and tubers. However, an increase in leaf area or root surface area would necessitate more investment in leaf or root dry mass, resulting in diminishing returns. For biomass allocation, tiger nut responded the same way to traditional fertilizer treatment and zero fertilizer treatment, but the tuber number and yield increase under traditional fertilizer application. Additional nitrogen fertilizer stimulated shoot production through accelerated rhizome production aided by leaf area increasing. Fertilizer application can significantly increase both the number of tiger nuts and tuber yield. Nitrogen addition positively influenced aboveground biomass and enhanced rhizome tillering. Strong adaptability of tiger nuts makes the plant a suitable pioneer crop for developing marginal lands. The robust aboveground growth after nitrogen application enhances suitability for pasture utilization.

High temperatures and low soil moisture synergistically reduce switchgrass yields from marginal field sites and inhibit fermentation

Abstract‘Marginal lands’ are low productivity sites abandoned from agriculture for reasons such as low or high soil water content, challenging topography, or nutrient deficiency. To avoid competition with crop production, cellulosic bioenergy crops have been proposed for cultivation on marginal lands, however on these sites they may be more strongly affected by environmental stresses such as low soil water content. In this study we used rainout shelters to induce low soil moisture on marginal lands and determine the effect of soil water stress on switchgrass growth and the subsequent production of bioethanol. Five marginal land sites that span a latitudinal gradient in Michigan and Wisconsin were planted to switchgrass in 2013 and during the 2018–2021 growing seasons were exposed to reduced precipitation under rainout shelters in comparison to ambient precipitation. The effect of reduced precipitation was related to the environmental conditions at each site and biofuel production metrics (switchgrass biomass yields and composition and ethanol production). During the first year (2018), the rainout shelters were designed with 60% rain exclusion, which did not affect biomass yields compared to ambient conditions at any of the field sites, but decreased switchgrass fermentability at the Wisconsin Central–Hancock site. In subsequent years, the shelters were redesigned to fully exclude rainfall, which led to reduced biomass yields and inhibited fermentation for three sites. When switchgrass was grown in soils with large reductions in moisture and increases in temperature, the potential for biofuel production was significantly reduced, exposing some of the challenges associated with producing biofuels from lignocellulosic biomass grown under drought conditions.

The silicon regulates microbiome diversity and plant defenses during cold stress in Glycine max L.

With climate change, frequent exposure of bioenergy and food crops, specifically soybean (Glycine max L.), to low-temperature episodes is a major obstacle in maintaining sustainable plant growth at early growth stages. Silicon (Si) is a quasi-essential nutrient that can help to improve stress tolerance; however, how Si and a combination of cold stress episodes influence plant growth, plant physiology, and microbiome diversity has yet to be fully discovered. The soybean plants were exposed to cold stress (8-10°C) with or without applying Si, and the different plant organs (shoot and root) and rhizospheric soil were subjected to microbiome analysis. The plant growth, physiology, and gene expression analysis of plant defenses during stress and Si were investigated. We showed that cold stress significantly retarded soybean plants' growth and biomass, whereas, Si-treated plants showed ameliorated negative impacts on plant growth at early seedling stages. The beneficial effects of Si were also evident from significantly reduced antioxidant activities - suggesting lower cold-induced oxidative stress. Interestingly, Si also downregulated critical genes of the abscisic acid pathway and osmotic regulation (9-cis-epoxy carotenoid dioxygenase and dehydration-responsive element binding protein) during cold stress. Si positively influenced alpha and beta diversities of bacterial and fungal microbiomes with or without cold stress. Results showed significant variation in microbiome composition in the rhizosphere (root and soil) and phyllosphere (shoot) in Si-treated plants with or without cold stress exposures. Among microbiome phyla, Proteobacteria, Bacteroidota, and Ascomycota were significantly more abundant in Si treatments in cold stress than in control conditions. For the core microbiome, we identified 179 taxa, including 88 unique bacterial genera in which Edaphobacter, Haliangium, and Streptomyces were highly abundant. Enhanced extracellular enzyme activities in the cold and Si+cold treatments, specifically phosphatase and glucosidases, also reflected the microbiome abundance. In conclusion, this work elucidates cold-mediated changes in microbiome diversity and plant growth, including the positive impact Si can have on cold tolerance at early soybean growth stages - a step toward understanding crop productivity and stress tolerance.