Search Results (1,700)

The Amazon Deforestation Arc remains a critical region for environmental governance, where land-use strategies must consider distinct legal and institutional frameworks across the Amazon and Cerrado biomes. This study applies the Potential Productivity Model (M3P), a theoretical radiation-based framework, to estimate the upper physiological limits of sugarcane (Saccharum officinarum L.) productivity on degraded pastures within the Arc of Deforestation. The model integrates satellite-derived solar radiation with climatic variables to quantify potential productivity under optimal biophysical conditions, providing an objective benchmark for planning-oriented bioenergy assessments. Estimated potential yields range from 153 to 178 t·ha⁻¹·yr⁻¹, consistent with global reference values reported for sugarcane in high-radiation environments and relevant for informing public policies such as Brazil’s Agroecological Zoning of Sugarcane. The results demonstrate that agroclimatic potential alone is insufficient to guide land-use decisions. While degraded pastures associated with the Cerrado biome may accommodate sugarcane cultivation as part of productive land recovery strategies, areas belonging to the Amazon biome require priority actions focused on ecological restoration through agroforestry and integrated crop–livestock–forest systems. Overall, the M3P model offers a scalable and scientifically grounded decision-support framework for strategic planning in environmentally sensitive tropical regions. Full article

Spodoptera frugiperda (fall armyworm, FAW) has rapidly spread across Asia and Africa in recent years, with its seasonal long-distance migration ability serving as the biological basis driving its region-wide outbreaks. Although the migratory biology of FAW has been extensively studied, it remains unclear whether there is stable differentiation between migratory and non-migratory individuals. In this study, we revealed the significant differences in morphological parameters between migratory populations and laboratory-reared populations. The migratory populations exhibited a greater body length and width and forewing size, as well as a lower body weight, compared to the laboratory colony. After three generations of indoor rearing, the migrants’ morphology and flight capacity converged to the laboratory phenotype, indicating the existence of a migratory ecotype in FAW. Through further investigation, a method for identifying the migratory ecotype of FAW was proposed based on the corrected wing loading (WL) and forewing aspect ratio (FA), which was successfully applied to distinguish individuals of the migratory ecotype in field populations. Our results confirm that FAWs exhibit stable differentiation into a migratory ecotype, and using WL and FA provides a robust, field-deployable tool for regional FAW monitoring, early warning systems, and targeted FAW control. Full article

Papaya (Carica papaya L.) is a tropical trioecious crop with males, hermaphrodites, and females. There is a sequence difference between male and hermaphrodite SHORT VEGETATIVE PHASE (CpSVP), making SVP a strong candidate gene controlling peduncle length in papaya. To study the spatial and temporal expression and function of CpSVP in Arabidopsis, we constructed a translation fusion structure based on the native promoter of SVP in papaya. In the 2kb promoter, strong GUS staining was observed in the floral organs and pedicels. In the 1kb promoter, there is no GUS expression in the floral organs, and it is barely detectable in pedicels. Removal of a GA responsive P-box cis-element in the 1kb promoter enhanced expression in the floral organs and pedicels, and elongated pedicels. In the transgenic Arabidopsis plants expressing the male CpSVP allele, there was an increase in pedicel length, but not in the plants expressing the hermaphrodite CpSVP allele. CpSVP-Y is capable of pedicel elongation, with no defects in reproductive organs. These findings imply that CpSVP-Y and this P-box play a major role in peduncle elongation but not sex determination in papaya. Full article

Silicon (Si) plays a critical role in regulating plant physiological processes, particularly through its influence on non-enzymatic antioxidant systems and amino acid metabolism. This study aims to assess soybean performance in response to both soil and foliar Si applications under well-watered and drought conditions, with the goal of enhancing Si accumulation in plant tissues and potentially strengthening the crop’s physiological responses to water deficit stress. This is especially pertinent given that the mechanisms underlying Si fertilization and its contribution to drought tolerance in soybean remain poorly understood. Greenhouse experiments were conducted using a 3 × 2 factorial design. The factors were: (i) three foliar Si treatments: control (no Si), potassium silicate (SiK; 128 g L⁻¹ Si, 126.5 g L⁻¹ K₂O, pH 12.0), and sorbitol-stabilized potassium silicate (SiKe; 107 g L⁻¹ Si, 28.4 g L⁻¹ K₂O, 100 mL L⁻¹ sorbitol, pH 11.8); and (ii) two soil water levels: well-watered (80% field capacity) and water-restricted (40% field capacity), the latter simulating tropical dry spells. Silicon was applied to the soil via irrigation and to the leaves via foliar spraying prior to the onset water restriction. All Si solutions were adjusted to pH 7.0 with 1 M HCl immediately before application. Potassium (K) levels were standardized across treatments through supplementary applications of KCl to both soil and foliage. Biometric and physiological parameters were subsequently measured. Sorbitol-stabilized Si enhanced Si accumulation in soybean tissues and improved plant resilience under both well-watered and drought conditions by promoting key physiological traits, including increased levels of daidzein and ascorbic acid levels, along with reduced amino acid concentrations. It also improved biometric parameters such as leaf area, root development, and number of pods per plant. These findings further support the role of Si as a beneficial element in enhancing stress tolerance and contributing to sustainable agricultural practices. Full article

Bacillus velezensis strain G2T39 is an endophytic bacterium previously isolated from Crotalaria retusa L., with evidenced biocontrol activity against Fusarium oxysporum f. sp. Cubense and Fusarium graminearum. In this study, it was shown that this strain also exhibited biocontrol activity against Colletotrichum gloeosporioides and Fusarium oxysporum f. sp. Vasinfectum, two important crop pathogens in tropical zones. Comprehensive phylogenetic and genomic analyses were performed to further characterize this strain. The genome of B. velezensis G2T39 consists of a single circular chromosome of 4,040,830 base pairs, with an average guanine–cytosine (GC) content of 46.35%. Both whole-genome-based phylogeny and average nucleotide identity (ANI) confirmed its identity as B. velezensis, being closely related to biocontrol and plant growth promotion Gram-positive model strains such as B. velezensis FZB42. Whole-genome annotation revealed 216 carbohydrate-active enzymes and 14 gene clusters responsible for secondary metabolite production, including surfactin, macrolactin, bacillaene, fengycin, bacillibactin, bacilysin, and difficidin. Genes involved in plant defense mechanisms were also identified. Additionally, G2T39 genome harbors multiple plant growth-promoting traits, such as genes associated with nitrogen metabolism (nifU, nifS, nifB, fixB, glnK) and a putative phosphate metabolism system (phyC, pst glpQA, ugpB, ugpC). Additional genes linked to biofilm formation, zinc solubilization, stress tolerance, siderophore production and regulation, nitrate reduction, riboflavin and nicotinamide synthesis, lactate metabolism, and homeostasis of potassium and magnesium were also identified. These findings highlight the genetic basis underlying the biocontrol capacity and plant growth-promoting properties of B. velezensis G2T39 and support its potential application as a sustainable bioinoculant in agriculture. Full article

In northwestern Ecuador, where more than 90% of the original forest cover has been lost, it is unknown how soil chemistry influences bat diversity. This study evaluated bat diversity, non-herbaceous plant community structure, and soil nutrients in 30 plots distributed across crops on two farms separated by 32 km. Soil analyses revealed variations in organic matter and nutrients, identifying calcium, magnesium, zinc and iron as the most influential. A total of 1662 individuals of 24 non-herbaceous plant species and 193 individuals of 16 bat species were recorded, dominated by frugivorous and nectarivorous guilds. Generalized linear mixed models showed significant relationships between bat diversity indices and soil nutrients. These elements improve tree growth, fruiting, and flowering, which increases the quality and availability of food resources for bats. In return, these mammals provide key ecosystem services such as pollination, seed dispersal, and insect control. Our findings highlight that soil chemistry indirectly regulates bat communities by influencing vegetation structure and resource availability. This integrated approach underscores the importance of soil–plant–animal interactions in tropical agricultural landscapes, offering practical guidance. Full article

Aromatic coconut (Cocos nucifera L.) is valued in the consumer market primarily for its distinctive fragrance, which is largely attributed to the compound 2-acetyl-1-pyrroline (2AP). The accumulation of 2AP has been observed in several crops, such as rice, when exposed to salt stress. In rice, exposure to salt stress influences the activity of enzymes, alters amino acid metabolism, and modulates the expression of genes associated with 2AP formation. Nevertheless, the processes responsible for 2AP biosynthesis in aromatic coconut under salt stress conditions are still not well clarified. In this study, five-month-old aromatic coconut seedlings were subjected to four distinct levels of sodium chloride (NaCl) treatment (0, 100, 200, and 300 mM). This experiment was conducted to investigate the mechanisms involved in salt-induced responses and the biosynthesis of 2AP in aromatic coconut. Although salt stress did not produce any apparent injury in the coconut seedlings, it led to a marked decline in chlorophyll content. Meanwhile, salt stress markedly enhanced the accumulation of betaine and boosted the activities of antioxidant enzymes such as superoxide dismutase and catalase. The aromatic coconut demonstrated a moderate level of salt tolerance. Salt stress also had a significant influence on 2AP biosynthesis. Under salt stress conditions, the 2AP content increased substantially, reaching its highest level with a 93.55% rise compared to the control. Furthermore, the synthesis of 2AP in aromatic coconut under salt stress appears to be primarily regulated through the metabolic pathways of proline and glutamate. Therefore, salt stress enhances 2AP production, with 200 mM NaCl identified as the optimal concentration for its accumulation. Full article

Fusarium oxysporum-induced soft rot severely threatens postharvest pitaya quality and storage life, and while vanillin shows promise in the disease management, its mechanisms for controlling pitaya decay remain incompletely understood. In this study, we systematically investigated the molecular mechanism by which vanillin inhibits soft rot in postharvest pitaya, employing physiological and biochemical characterization, bioinformatics analysis, and molecular biology techniques. Compared with control fruit on 10 d, vanillin treatment significantly reduced disease index and lesion area by 27.12% and 67.43%, respectively. Meanwhile, vanillin treatment delayed the degradation of total soluble solids (TSSs) and titratable acidity (TA) and promoted the accumulation of total phenolics and flavonoids. Additionally, vanillin enhanced the activities of defense-related enzymes, such as catalase (CAT), superoxide dismutase (SOD), phenylalanine ammonia-lyase (PAL), β-1,3-glucanase (GLU), chitinase (CHI), peroxidase (POD) and polyphenol oxidase (PPO), and increased antioxidant capacity, as evidenced by increased DPPH radical scavenging capacity and ascorbic acid content. This resulted in reduced oxidative damage, as indicated by decreased levels of malondialdehyde (MDA), H₂O₂ and O₂^•−. Yeast one-hybrid (Y1H), dual-luciferase reporter (DLR) and subcellular localization revealed that HuTGA1, a nuclear-localized transcriptional activator, specifically bound to the as-1 cis-acting element and activated expression of HuNPR1 and HuNPR5-1. Transient overexpression of HuTGA1 reduced reactive oxygen species (ROS) accumulation and upregulated related genes. These findings suggest that vanillin treatment might enhance pitaya resistance by activating the HuTGA1-HuNPR signaling module, providing insights into the molecular mechanisms underlying vanillin-induced resistance. Full article

Background: Polysaccharides modulate host health by interacting with gut microbiota and reshaping the host–microbial metabolome, potentially facilitating immune regulation. Methods: This study evaluated the modulatory effect of Artocarpus heterophyllus Lam. (jackfruit) polysaccharide (JFP-Ps) against cyclophosphamide (Cy)-induced immunosuppression in mice, focusing on gut microbiota modulation and metabolite changes. Results: JFP-Ps effectively increased the beneficial bacteria ratio, such as Lactobacillus and Lachnospiraceae, while inhibiting some species like Akkermansia. Metabolomic analysis showed that JFP-Ps notably regulated gut microbe-associated metabolites, including short-chain fatty acids (SCFAs), amino acids, bile acids, indoles, and derivatives. These metabolites were involved in various metabolic pathways, including primary bile acid synthesis and biosynthesis of phenylalanine, tyrosine, and tryptophan, along with tryptophan catabolism, purine metabolic processes, and unsaturated fatty acid production. Additionally, significant correlations between microbial groups and functional metabolites were identified. Overall, JFP-Ps exerted an immuno-modulatory effect by reshaping gut microbiota and enhancing co-metabolism with the host. Conclusions: These results provided valuable insights into host–microbiota interactions and gut microbiota-targeted intervention strategies of tropical natural bioactive polysaccharides. Full article

Agrivoltaics (APV) offers a promising dual land-use solution for food and energy production, yet empirical data regarding its impact on leguminous crops in tropical monsoon climates remain limited. This study evaluated the microclimate, growth, and yield of soybean (Glycine max) under an APV system compared to an open-field control during the wet and dry seasons in Bogor, Indonesia. The APV structure reduced incident solar radiation by approximately 35%, significantly lowering soil temperatures and maintaining higher soil moisture across both seasons. In the wet season, the APV treatment significantly increased grain yield (3528.8 vs. 1708.3 kg ha⁻¹, +106%) relative to the open field by mitigating excessive heat and radiative loads, which enhanced pod retention. In the dry season, APV maintained a yield advantage (2025.6 vs. 1724.4 kg ha⁻¹, +17%), driven by improved water conservation and a higher harvest index. Notably, shading did not delay phenological development or hinder vegetative growth in either season. These findings demonstrate that APV systems can contribute to sustainably higher yields and stability in tropical environments by buffering against season-specific environmental stresses, suggesting a viable pathway for sustainable agricultural intensification in equatorial regions. Full article

Acetylcholinesterase (AChE) is an important molecular target in the development of insecticides, but due to also being found in the human body, it is necessary to characterize the inhibitory profile of compounds to achieve selectivity. In this study, we employed molecular modeling and 3D-QSAR approaches to identify novel compounds that inhibit AChE1 in Bemisia tabaci, a common agricultural pest in tropical and subtropical crops. We conducted molecular docking simulations and quantitative structure–activity relationship analysis (QSAR) to identify compounds with potential inhibitory activity and to develop a predictive model for the activity of these new compounds. The validated model demonstrated remarkable predictive performance. Using the model, we screened a library of novel moieties in favorable regions of the most active molecules in the dataset and identified promising candidates, including FS168. We performed molecular dynamics simulations with FS168 bound to the AChE1 of B. tabaci and observed stabilization and interaction with important catalytic amino acids, indicating a potential inhibition mechanism. Our results showcase the potential of combining molecular modeling and 3D-QSAR approaches for discovering new potential AChE1 inhibitors in Bemisia tabaci as selective agrochemicals. Full article

Intermittent Hypobaric Storage (IHS) effectively inhibits postharvest deterioration of cassava roots, yet its physiological regulatory mechanisms and associated quality alterations remain poorly understood. This study investigated the regulatory mechanisms of root respiratory physiology under IHS and their impact on quality. Results indicate that IHS reduces root respiration rates and maintains generally low anaerobic respiration enzyme activity, while ATP content remains higher than in the control. This supports efficient energy supply for cellular metabolism, thereby delaying senescence. Transcriptomic analysis revealed that IHS modulates glycolytic genes, suppresses excessive anaerobic respiration, and upregulates pathways associated with ribosome biogenesis and oxygen response. Meanwhile, IHS downregulated ATP-consuming pathways involved in phenylpropanoid biosynthesis. IHS effectively prolongs shelf life and preserves the nutritional quality of cassava roots, maintaining levels comparable to those of fresh roots. These molecular responses collectively support the physiological and biochemical benefits of IHS, providing valuable insights for optimizing its application in cassava postharvest storage. Full article

Longan (Dimocarpus longan Lour.) is a commercially valuable tropical fruit crop that contains two antagonistic FLOWERING LOCUS T (FT) homologs involved in regulating flowering time. However, how these FT genes interact with flowering regulators FLOWERING LOCUS D (FD) and APETALA1 (AP1) remains unknown. Four flowering-related genes in longan, DlFT1, DlFT2, DlAP1 and DlFD, were successfully isolated. Expression profiling revealed that all four genes were expressed in leaves and buds across different stages of natural and KClO₃-induced floral bud differentiation. Functional characterization through heterologous overexpression in Arabidopsis thaliana showed that DlAP1 significantly promotes early flowering under long-day conditions and induced morphological changes in floral organs and leaves. In contrast, DlFD overexpression had no effect on flowering time. Subcellular localization assays revealed that DlFT1 and DlFT2 localized to both the nucleus and the plasma membrane, while DlAP1 and DlFD localized exclusively to the nucleus. Yeast two-hybrid and bimolecular fluorescence complementation (BiFC) analyses revealed a novel regulatory node: DlFT1 directly interacts with DlAP1, a finding that expands the classical FT-FD-AP1 flowering model. Additionally, DlFD interacts more strongly with DlFT1 than with DlFT2, whereas DlFT1 only interacts with DlAP1, but not DlFT2. These results demonstrate that DlFT1 promotes flowering not only via the conserved FD-dependent pathway but also through direct association with AP1. These findings advance our understanding of the regulatory mechanisms of flowering in longan and provide valuable insights into flowering pathways of perennial woody species. Full article

Heat stress caused a stagnation in the growth and development of Passiflora edulis Sims. To investigate the effects of high-temperature stress, this study subjected P. edulis to 40 °C treatment for different durations; the changes in chlorophyll content, chlorophyll fluorescence parameters, photosynthetic parameters, transcriptome profiles, and photosynthesis-related genes of P. edulis under high-temperature stress were analyzed. The results showed that after 5 h of heat stress, the chlorophyll content of the leaves decreased by 31%, variable fluorescence/maximum fluorescence (Fv/Fm) decreased by 26.91%, photochemical performance index (PI_abs) by 99.28%, comprehensive performance index (PI_total) by 94.20%, light energy absorbed per unit area (ABS/CSm) by 13.56%, light energy captured per unit area (TRo/CSm) by 17.90% and quantum yield of electron transfer per unit area (ETo/CSm) by 92.61%. The net photosynthetic rate (Pn), transpiration rate (Tr) and stomatal conductance (Gs) decreased by 47%, 41% and 38%, respectively, while intercellular CO₂ concentration (Ci) increased by 1.34 times. Transcriptome sequencing results of P. edulis under heat stress identified 2336 differentially expressed genes (DEGs), which were significantly enriched in pathways including chloroplast function and plant hormone signal transduction. GO enrichment analysis demonstrated that DEGs were significantly enriched in terms related to catalytic activity and chloroplast components. Concurrently, KEGG pathway analysis revealed that carbon fixation in photosynthetic organisms was among the key pathways showing significant enrichment of these DEGs. The expression levels of photosynthesis-related genes, including PePSAE, PeMADs, PebHLH, PeFAR1, PePSBS, PePnsB4, PebZIP and PeC2H2, exhibited a significant increase after 3 h of high-temperature stress and rapidly declined following 5 h. These findings lay a foundation for further research on the high-temperature stress response mechanism and photosynthetic regulation of heat tolerance in P. edulis. Full article

Using cover crops (CCs) following annual crops, together with sustainable nitrogen (N) management, significantly enhances soil carbon (C) storage. However, carbon accumulation in tropical soils is strongly influenced by the respective crop sequences. This study evaluated soil C stocks and fractions in a system incorporating maize–soybean rotation and successive CCs. A randomized block design with split plots was implemented, where main plots consisted of different CCs and the subplots of treatments with and without N fertilization of maize. Chemical fractions of soil organic matter (SOM) were analyzed at depths from 0 to 40 cm, and C stocks down to 100 cm. The SOM fractions responded to N topdressing of maize, varying with soil depth. Soil C stocks during the maize phase were significantly higher than during soybean cultivation (p < 0.05), likely reflecting greater residue inputs from species with elevated C:N ratios. Legume crops following maize intensified C accumulation, emphasizing the importance of N inputs for soil C dynamics. Soil C losses were lowest in the treatments with Raphanus sativus without and Crotalaria juncea with N fertilization. These findings highlight the relevance of combining CCs and N management to optimize C sequestration in tropical agroecosystems. Full article