Plant Species Research Articles

Evolution of antioxidant potential during fruit maturation Pancovia laurentii (De Wild.) Gilg ex De (Sapindaceae)

Pancovia laurentii (De Wild.) Gilg ex De (Sapindaceae) is a plant species of the spontaneous flora of Central Africa, which grows easily in the Republic of Congo. It produces very succulent edible fruits. The evaluation of phenolic compounds and antioxidant activity in the pulp and seed of the fruit during its maturation was done by spectrophotometer. The results reveal the increase of total polyphenols, total flavonoids and anthocyanins in the pulp and seed of the fruit during maturation. Flavonoids accumulate more in the seed than in the pulp. At taste maturity, the seed with 400.85 mg EQ/DM is richer in flavonoids than the pulp which has 322.26 mg EQ/DM. Polyphenols and anthocyanins accumulate more in the pulp than in the seed with respectively 432.8 mg EAG/mg DM for polyphenols and 157.50 mg/mL for anthocyanins. The pulp and seed presented a DPPH radical scavenging activity. The antioxidant activity increases during maturation. It is greater than 50%, particularly in the pulp with 0.25 mg/mL and in the seed with 0.37 μg/mL at taste maturity. These results show the existence of a good linear correlation between the content of total polyphenols, total flavonoids, anthocyanins and the antioxidant power of the pulp and seed of the fruit during maturation. With these contents, the fruit can be considered as a potential source of natural antioxidants.

Classified Plant Al-Dhahiriya in the South of Palestine

We studied plant species of Dhahiriya in the period between January to October 2021, and January to Jun 2024, due to the importance of plants in that vital part of Palestine, which is located in southern Palestine, including that region’s climate, and unique plants that represent of the Mediterranean region plants, North Africa, Sinai desert, Negev, Dead Sea, and Red Sea. It used the Braun-Blanquet (1979) method for the identification of plants. Moreover, Plants have been studied in Dhahiriya, located in southern Palestine. A total of 770 species from 70 families were identified, of which 86 (11.16%) are endemic. The plant families with the highest representation were Asteraceae (14.54%), Fabaceae (14%), Poaceae (7.41%), and Lamiaceae (5.19%). Regarding plant life forms, Therophytes account for 47%, Hemicryptophytes for 20.35%, Shrubs or Chamaephytes for 14.05%, and Trees or Phanerophytes for 9.05%, with a notable increase in spring.

Women's preferences for associated species in cocoa-based agroforestry systems and their uses in the Kokumbo Sub-Prefecture (Côte d'Ivoire)

Due to their multiple uses, species associated with cocoa trees have an important socio-economic and environmental value for women in Central Côte d'Ivoire. Based on surveys followed by an inventory carried out in six villages of the Sous-Préfecture of Kokumbo, this study assesses women's preference for cocoa companion species using the pebble distribution method, in order to quantify the value accorded by the latter according to their various uses. A total of 79 plant species were identified, divided into 67 genera and 31 families. These species associated with cocoa trees have an explicit value for women, as they meet the vital needs of farming households, such as self-consumption (43.32%), sale (35.21%), shade (7.53%), timber and firewood (7.15%). Using the pebble distribution method, we have highlighted the most important species associated with cocoa trees for women. For self-consumption, we have Dioscorea spp with 29.47% and Musa paradisiaca (18%). They attribute a high commercial value to Musa paradisiaca (25%) and Persea americana (21%). They also prefer species that provide good shade for cocoa trees, such as Ceiba pentandra (19.74%) and Milicia excelsa (11.30%). Those that provide good firewood and energy, such as Milicia excelsa (28%) and Albizia zygia (19%). Domestication of the tree and shrub species most appreciated by farmers could stimulate their regeneration. The marketing of products from cocoa agroforests could enable women to acquire financial autonomy in order to improve the living conditions of their households in general and those of their children in particular.

Genome-wide identification of a MADS-box transcription factor family and their expression during floral development in Coptis teeta wall

BackgroundMADS-box transcription factors have been shown to be involved in multiple developmental processes, including the regulation of floral organ formation and pollen maturation. However, the role of the MADS-box gene family in floral development of the alpine plant species Coptis teeta Wall, which is widely used in Traditional Chinese Medicine (TCM), is unknown.ResultsSixty-six MADS-box genes were identified in the C. teeta genome. These genes were shown to be unevenly distributed throughout the genome of C. teeta. The majority of which (49) were classified as type I MADS-box genes and were further subdivided into four groups (Mα, Mβ, Mγ and Mδ). The remainder were identified as belonging to the type II MADS-box gene category. It was observed that four pairs of segmental and tandem duplication had occurred in the C. teeta MADS-box gene family, and that the ratios of Ka/Ks were less than 1, suggesting that these genes may have experienced purifying selection during evolution. Gene expression profiling analysis revealed that 38 MADS-box genes displayed differential expression patterns between the M and F floral phenotypes. Sixteen of these MADS-box genes were further verified by RT-qPCR. The 3D structure of each subfamily gene was predicted, further indicating that MADS-box genes of the same type possess structural similarities to the known template.ConclusionsThese data provide new insights into the molecular mechanism of dichogamy and herkogamy formation in C. teeta and establish a solid foundation for future studies of the MADS-box genes family in this medicinal plant species.

Effects of multiple mammalian herbivores and climate on grassland-shrubland transitions in the Chihuahuan Desert.

The replacement of grasses by shrubs or bare ground (xerification) is a primary form of landscape change in drylands globally with consequences for ecosystem services. The potential for wild herbivores to trigger or reinforce shrubland states may be underappreciated, however, and comparative analyses across herbivore taxa are sparse. We sought to clarify the relative effects of domestic cattle, native rodents, native lagomorphs, and exotic African oryx (Oryx gazella) on a Chihuahuan Desert grassland undergoing shrub encroachment. We then asked whether drought periods, wet season precipitation, or interspecific grass-shrub competition modified herbivore effects to alter plant cover, species diversity, or community composition. We established a long-term experiment with hierarchical herbivore exclosure treatments and surveyed plant foliar cover over 25 years. Cover of honey mesquite (Prosopis glandulosa) proliferated, responding primarily to climate, and was unaffected by herbivore treatments. Surprisingly, cattle and African oryx exclusion had only marginal effects on perennial grass cover at their current densities. Native lagomorphs interacted with climate to limit perennial grass cover during wet periods. Native rodents strongly decreased plant diversity, decreased evenness, and altered community composition. Overall, we found no evidence of mammalian herbivores facilitating or inhibiting shrub encroachment, but native small mammals interacting with climate drove dynamics of herbaceous plant communities. Ongoing monitoring will determine whether increased perennial grass cover from exclusion of native lagomorphs and rodents slows the transition to a dense shrubland.

Regulatory options for cultivars and hybrids of invasive plant species – the South African experience

Abstract Invasive plant taxa are generally regulated at the species level, without considering infra- or inter-specific variation. However, cultivars or hybrids can be of a lower level of risk, e.g., due to sterility. We evaluate six general approaches to regulating cultivars and hybrids -1) “Globally guilty by association”; 2) “Nationally guilty by association”; 3) “Guilty until proven innocent”; 4) “Negotiated guilt”; 5) “Claimed to be innocent”; and 6) “Innocent until proven guilty”. We discuss these approaches in the context of South Africa (which has a typified “Negotiated guilt” approach). Following negotiations since 2001 between the South African horticultural industry/green industry and legislators, an unofficial consensus list of “presumed sterile” cultivars and hybrids was produced in 2014 containing 187 entities from 34 taxa. In 2020 this was reduced to 157 entities from 16 taxa. But the evidence supporting the original lists and the subsequent revisions were not published. To address this issue, we developed a generic pro-forma for reporting sterility based on observations and/or experiments on: flowering, fruiting, pollen, and seeds; the potential for vegetation propagation; and the potential for genetic changes (including hybridisation and reversion to fertility). We recommend that such information should be incorporated into risk analyses conducted specifically for infra- and inter- specific entities, and only if the risk of a harmful invasion is demonstrated to be acceptably low or can be easily mitigated should such entities be exempted from regulation. This will be time-consuming, but by setting out the evidence clearly, the approach is transparent and provides a clear route for stakeholders to seek exemptions for entities of importance. In summary, although we suspect the simplicity of the “Negotiated guilt” approach is desirable to many stakeholders; in general, and specifically for South Africa, we recommend a shift towards the “Guilty until proven innocent” approach.

Advancements in plant transformation: from traditional methods to cutting-edge techniques and emerging model species.

The ability to efficiently genetically modify plant species is crucial, driving the need for innovative technologies in plant biotechnology. Existing plant genetic transformation systems include Agrobacterium-mediated transformation, biolistics, protoplast-based methods, and nanoparticle techniques. Despite these diverse methods, many species exhibit resistance to transformation, limiting the applicability of most published methods to specific species or genotypes. Tissue culture remains a significant barrier for most species, although other barriers exist. These include the infection and regeneration stages in Agrobacterium, cell death and genomic instability in biolistics, the creation and regeneration of protoplasts for protoplast-based methods, and the difficulty of achieving stable transformation with nanoparticles. To develop species-independent transformation methods, it is essential to address these transformation bottlenecks. This review examines recent advancements in plant biotechnology, highlighting both new and existing techniques that have improved the success rates of plant transformations. Additionally, several newly emerged plant model systems that have benefited from these technological advancements are also discussed.

NcPlantDB: a plant ncRNA database with potential ncPEP information and cell type-specific interaction.

The field of plant non-coding RNAs (ncRNAs) has seen significant advancements in recent years, with many ncRNAs recognized as important regulators of gene expression during plant development and stress responses. Moreover, the coding potential of these ncRNAs, giving rise to ncRNA-encoded peptides (ncPEPs), has emerged as an essential area of study. However, existing plant ncRNA databases lack comprehensive information on ncRNA-encoded peptides (ncPEPs) and cell type-specific interactions. To address this gap, we present ncPlantDB (https://bis.zju.edu.cn/ncPlantDB), a comprehensive database integrating ncRNA and ncPEP data across 43 plant species. ncPlantDB encompasses 353 140 ncRNAs, 3799 ncPEPs and 4 647 071 interactions, sourced from established databases and literature mining. The database offers unique features including translational potential data, cell-specific interaction networks derived from single-cell RNA sequencing and Ribo-seq analyses, and interactive visualization tools. ncPlantDB provides a user-friendly interface for exploring ncRNA expression patterns at the single-cell level, facilitating the discovery of tissue-specific ncRNAs and potential ncPEPs. By integrating diverse data types and offering advanced analytical tools, ncPlantDB serves as a valuable resource for researchers investigating plant ncRNA functions, interactions, and their potential coding capacity. This database significantly enhances our understanding of plant ncRNA biology and opens new avenues for exploring the complex regulatory networks in plant genomics.

Checklist and prioritization of crop wild relatives in Sudan and South Sudan

Crop wild relatives (CWR) encompass wild plant species or subspecies closely related to domesticated crops. This study presents the first comprehensive checklist and prioritized inventory of CWR for Sudan and South Sudan. Building on the regional CWR list for Northeast Africa, we identified 499 CWR taxa belonging to 44 families, with 90% of these being native species. The most prominently represented families were Poaceae (148), Fabaceace (72) and Convolvulaceae (43), while Panicum (32), Eragrostis (27), Ficus (24) and Pennisetum (20) were the most frequent genera. A prioritized inventory of 85 CWR taxa was developed based on three criteria: economic value, utilization potential and threat status. The prioritized CWR are predominately native (78%) and encompass 12 families dominated by Poaceae (38), followed by Solanaceae (9), Fabaceae (6) and Cucurbitaceae (6). Priority genera included 27, with Digitaria (17), Solanum (9) and Cucumis (5) emerging as key genera for conservation attention. This comprehensive national CWR inventory provides a crucial foundation for developing targeted conservation strategies in Sudan and South Sudan.

A Mycorrhiza-Induced UDP-Glucosyl Transferase Negatively Regulates the Arbuscular Mycorrhizal Symbiosis.

Most terrestrial plants can establish a reciprocal symbiosis with arbuscular mycorrhizal (AM) fungi to cope with adverse environmental stresses. The development of AM symbiosis is energetically costly and needs to be dynamically controlled by plants to maintain the association at mutual beneficial levels. Multiple components involved in the autoregulation of mycorrhiza (AOM) have been recently identified from several plant species; however, the mechanisms underlying the feedback regulation of AM symbiosis remain largely unknown. Here, we report that AM colonization promotes the flavonol biosynthesis pathway in tomato (Solanum lycopersicum), and an AM-specific UDP-glucosyltransferase SlUGT132, which probably has the flavonol glycosylation activity, negatively regulates AM development. SlUGT132 was predominantly expressed in the arbuscule-containing cells, and its knockout or knockdown mutants showed increased soluble sugar content, root colonization level and arbuscule formation. Conversely, overexpression of SlUGT132 resulted in declined soluble sugar content and mycorrhization degree. Metabolomic assay revealed decreased contents of astragalin, tiliroside and cynaroside in slugt132 mycorrhizal roots, but increased accumulation of these flavonoid glycosides in SlUGT132-overexpressing plant roots. Our results highlight the presence of a novel, SlUGT132-mediated AOM mechanism, which enable plants to flexibly control the accumulation of soluble sugars and flavonoid glycosides in mycorrhizal roots and modulate colonization levels.

Winter leaf phenology differences facilitate selective control of an invasive plant species by herbicide

Herbicide control of invasive plant species is generally efficient. However, there is a likelihood of the excessive application of non-selective herbicides that kill co-occurring native species and cause environmental toxicity. We present a case study on the control of the invasive exotic Solidago canadensis with photosynthetically active leaves in winter by applying glyphosate. This approach improves herbicide control efficiency, while preventing harm to most co-occurring native plants. We quantified the winter leaf phenology and photosynthetic capacity of S. canadensis and two commonly co-occurring native species. We tested the effects of glyphosate and competition on S. canadensis and native Imperata cylindrica with contrasting winter leaf phenology in both pot and field experiments. Finally, we surveyed the life forms and winter leaf phenology of most co-occurring plant species in eastern China to determine whether most co-occurring species and S. canadensis differ in winter leaf phenology. Old leaves withered much later and new leaves developed much earlier in S. canadensis than in the two co-occurring species. Both the old and new leaves of S. canadensis had high photosynthetic capacity in winter. In summer, glyphosate suppressed the growth of S. canadensis by 20.1–59.5% and growth of I. cylindrica to a greater extent (by 57.6–91.7%), whereas winter application of glyphosate at a certain concentration suppressed the growth of S. canadensis by 91.4–95.6% (the efficiency was higher than summer application), but had no impact on I. cylindrica. Glyphosate application in winter alleviated competition stress from S. canadensis on I. cylindrica. We conclude that winter glyphosate application can increase the selectivity and efficiency of chemical control of invasive S. canadensis, which may shift the competition balance towards native species and favour native vegetation recovery in sites invaded by S. canadensis. The principles of this approach can be applied to any scenario where invasive species and co-occurring species have distinct phenological niche separation.

Effect of the culture liquid of Antarctic yeast <i>Nadsoniella nigra</i> on rooting, growth, and biochemical composition of <i>in vitro</i> grapevine (<i>Vitis vinifera</i> L.), cultivar '<i>Karmrahyut</i>'

Background: Grapevine (Vitis vinifera L.) is a globally significant fruit crop known for its nutritional and health benefits, including its role in preventing chronic diseases such as cancer and cardiovascular disorders. The bioactive compounds in grapes contribute to these benefits. Bioactive content changes due to grapevine variety and environmental conditions necessitate ongoing research. In vitro propagation provides a controlled environment for grapevine cultivation, minimizing disease risk and ensuring consistent quality. This study investigates the potential of Nadsoniella nigra (Nn), an Antarctic yeast, as a natural alternative to synthetic auxins like Indole-3-butyric acid (IBA) in grapevine micro cutting propagation. Objective: To evaluate the effectiveness of the culture liquid of Nn as a natural alternative to auxin-class hormones, using IBA as an example, for promoting rooting in grapevine microcuttings and to assess its impact on chlorophyll content, vitamin C levels, and sugar concentrations. Materials and Methods: In vitro propagation of grapevine (Vitis vinifera L.) cultivar 'Karmarhyt' was performed using half-strength Woody Plant Medium (WPM). Nn culture liquid was prepared at concentrations of 0.5, 1.0, 1.5, and 2.0 ml/L, and IBA was used at equivalent concentrations. Microcuttings were cultured on media supplemented with these treatments, with a control group maintained without growth regulators. Rooting was evaluated after 4 weeks by measuring rooting percentage, number of roots per shoot, and root length. Chlorophyll a (Chl a) and Chlorophyll b (Chl b) levels, vitamin C content, and sugar concentrations were assessed. Statistical analysis was performed using standard error and t-tests. Results: Rooting performance of grapevine microcuttings varied with treatment. Nn culture liquid promoted rooting in a dose-dependent manner, with the highest values observed at 2.0 ml/L (97.0% rooting, 7.2 roots, 13.8 cm root length). IBA treatment resulted in peak rooting at 1.0 mg/L (100% rooting) but decreased at higher concentrations, accompanied by callus formation. Chlorophyll content was higher in Nn culture liquid treated microcuttings, with a maximum total chlorophyll of 2.20 mg/g at 2.0 mg/L, compared to a peak of 2.05 mg/g in IBA-treated microcuttings at 1.0 mg/L. Sugar and vitamin C content increased with Nn culture liquid concentrations, whereas IBA showed a less consistent effect. Conclusion: Nn culture liquid was an effective natural alternative to IBA for promoting rooting in grapevine microcuttings. It improved rooting efficiency, chlorophyll content, and increased sugar and vitamin C levels, while IBA led to growth inhibition and callus formation at higher concentrations. Nn culture liquid demonstrated consistent benefits, suggesting potential for sustainable viticulture. As a result of the conducted research, it was established that the mixture of secondary metabolites contained in the liquid culture medium of Nn possesses high biological activity and can be recommended for use in plant biotechnology in vitro to promote the growth of both underground and above-ground parts. Future research could explore its use in propagating other plant species. Keywords: ´Karmrahyut´, grapevine, culture liquid of Nadsoniella nigra. in vitro propagation, functional foods

Deep learning modeling of RNA ac4C deposition reveals the importance of plant alternative splicing.

The N4-acetylcytidine (ac4C) modification has recently been characterized as a noncanonical RNA marker in plants. While the precise installation of ac4C sites in individual plant transcripts continues to present challenges, the biological roles of ac4C in specific plant species are gradually being deciphered. Herein, we utilized a deep learning technique called iac4C (intelligent ac4C) to predict ac4C sites in mRNA. ac4C deposition was effectively forecasted by the iac4C model (AUROC = 0.948), revealing a reliable distribution pattern primarily situated in the transcribing area as opposed to regions that are not translated. The iac4C deep learning approach using a combination of BiGRU and self-attention mechanisms both validates previous studies showing a positive correlation between ac4C and RNA splicing in plant species and reveals new examples of other splicing events associated with ac4C. Our advanced deep learning algorithm for analyzing ac4C enables swift identification of important biological phenomena that would otherwise be challenging to uncover through traditional experimental approaches. These findings provide insight into the essential regulatory function of site-specific ac4C deposition in alternative splicing processes. The source code and datasets for iac4C are available at https://github.com/xlwei507/iac4C .

Mathematical modeling predicts that endemics by generalist insects are eradicated if nearly all plants produce constitutive defense

Plants with constitutive defense chemicals exist widely in nature. The phenomenon is backed by abundant data from plant chemical ecology. Sufficient data are also available to conclude that plant defenses act as deterrent and repellent to attacking herbivores, particularly deleterious generalist insects. In the wild, generalist species are usually not endemic, meaning they are not restricted to certain plant species in a region. Therefore, our objective is to inspect theoretically whether evolution of chemical defenses in all plant species eradicate an endemic by any generalist species. The objective is addressed by developing deterministic ordinary differential equations under the following conditions: Plants without constitutive defenses are susceptible to oviposition by generalist insects, while they become defended against generalists by storing chemical defenses. From the models, we explicitly obtain that a generalist-free stable state is only possible if the vast majority of all plant individuals have chemical defenses. The model also allows one to predict the highest possible percentage of undefended plant individuals, which may be considered as free-riders.

Research Progress of Single-Cell Transcriptome Sequencing Technology in Plants

Multicellular organisms exhibit inherent cellular heterogeneity that cannot be captured by traditional high-throughput sequencing techniques, resulting in the unique cellular characteristics of individual cells being neglected. Single-cell transcriptome sequencing (scRNA-seq) technology can be used to determine the gene expression levels of each individual cell, facilitating the study of intercellular expression heterogeneity. This review provides a comprehensive overview of the development and applications of scRNA-seq technology in plant research. We highlight the significance of integrating single-cell multi-omics approaches to achieve a holistic understanding of plant systems. Additionally, we discuss the current challenges and future research directions for scRNA-seq technology in plant studies, aiming to offer valuable insights for its application across various plant species.

Genome-Wide Data Uncover Cryptic Diversity With Multiple Reticulation Events in the Balkan-Anatolian Cardamine (Brassicaceae) Species Complex.

Plant species diversity may be considerably underestimated, especially in evolutionarily complex genera and in diversity hotspots that have enabled long-term species persistence and diversification, such as the Balkan Peninsula. Here, we address the topic of underexplored plant diversity and underlying evolutionary and biogeographic processes by investigating the hygrophytic mountain species complex of Cardamine acris s.l. distributed in the Balkans (three subspecies within C. acris) and northwestern Anatolia (C. anatolica). We performed a series of phylogenetic and phylogeographic analyses based on restriction-site associated DNA sequencing (RADseq) and target enrichment (Hyb-Seq) data in combination with habitat suitability modelling. We found C. anatolica as a clade nested within the Balkan C. acris, probably resulting from a founder event, and uncovered three allopatric cryptic lineages within C. acris subsp. acris, allowing us to recognise a total of six entities in this complex. We observed the deepest genetic split within C. acris subsp. acris in the western Balkans, which was at odds with taxonomy and showed no distribution gap. We inferred vicariance as the most likely process for population divergence in the Balkans, accompanied by gene flow between the recognised entities, which was consistent with the modelled habitat suitability dynamics. Furthermore, we discovered several polyploid populations in C. acris, representing both pure intra- and inter-lineage hybrid polyploids, but detected only minor traces of hybridization with related congeners. Overall, our results illustrate that diverse evolutionary processes may influence the history of mountain plant species in the Balkan Peninsula, including vicariance, reticulation, polyploidization and cryptic diversification.

Vishniacozyma floricola sp. nov., a flower-related tremellomycetous yeast species from Europe.

During the course of two independent studies conducted in Hungary and Spain, four conspecific yeast strains were isolated from flowers of different plant species. DNA sequences of two barcoding regions, the D1/D2 domain of the LSU rRNA gene and the internal transcribed spacer (ITS) region (ITS1-5.8S rRNA gene-ITS2), revealed that the four strains represent an undescribed Vishniacozyma (family Bulleribasidiaceae, Basidiomycota) species. In terms of pairwise sequence similarities and according to our phylogenetic analyses of the concatenated DNA sequences of the ITS region and the D1/D2 domain of the LSU rRNA gene, the undescribed species is most closely related to Vishniacozyma melezitolytica, a yeast species of phylloplane origin. The novel species differs from the type strain of V. melezitolytica by 8 substitutions and 3 insertion/deletion (indels) and 11 substitutions and 5 indels along the D1/D2 domain of the LSU rRNA gene and the ITS region, respectively. In addition to the DNA sequence divergences, the two species differ in some physiological characters as well. We propose the species Vishniacozyma floricola sp. nov. to accommodate the above-noted strains (holotype, NCAIM Y.02320; isotype, CBS 18939; MycoBank number, 856028).

Cathepsin B- and L-like Protease Activities Are Induced During Developmental Barley Leaf Senescence

Leaf senescence is a developmental process allowing nutrient remobilization to sink organs. Previously cysteine proteases have been found to be highly expressed during leaf senescence in different plant species. Using biochemical and immunoblotting approaches, we characterized developmental senescence of barley (Hordeum vulgare L. var. ‘GemCraft’) leaves collected from 0 to 6 weeks after the onset of flowering. A decrease in total protein and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunits occurred in parallel with an increase in proteolytic activity measured using the fluorogenic substrates Z-RR-AMC, Z-FR-AMC, and casein labeled with fluorescein isothiocyanate (casein-FITC). Aminopeptidase activity detected with R-AMC peaked at week 3 and then decreased, reaching a low level by week 6. Maximal proteolytic activity with Z-FR-AMC and Z-RR-AMC was detected from pH 4.0 to pH 5.5 and pH 6.5 to pH 7.4, respectively, while two pH optima (pH 3.6 to pH 4.5 and pH 6.5 to pH 7.4) were found for casein-FITC. Compound E-64, an irreversible cysteine protease inhibitor, and CAA0225, a selective cathepsin L inhibitor, effectively inhibited proteolytic activity with IC50 values in the nanomolar range. CA-074, a selective cathepsin B inhibitor, was less potent under the same experimental conditions, with IC50 in the micromolar range. Inhibition by leupeptin and phenylmethylsulfonyl fluoride (PMSF) was weak, and pepstatin A, an inhibitor of aspartic acid proteases, had no effect at the concentrations studied (up to 0.2 mM). Maximal proteolytic activity with the aminopeptidase substrate R-AMC was detected from pH 7.0 to pH 8.0. The pH profile of DCG-04 (a biotinylated activity probe derived from E-64) binding corresponded to that found with Z-FR-AMC, suggesting that the major active proteases are related to cathepsins B and L. Moreover, immunoblotting detected increased levels of barley SAG12 orthologs and aleurain, confirming a possible role of these enzymes in senescing leaves.

Effect of microplastics on the allelopathic effects of native and invasive plants on co-occurring invaders

IntroductionMicroplastic pollution has emerged as a significant global change factor, with the potential to alter the biological, physicochemical properties of soil and to subsequently affect plant growth. Despite growing recognition of the impacts of microplastic pollution, the mechanisms by which microplastics modify plant leaf chemistry and influence allelopathic interactions among co-existing plant species remain unclear.MethodsWe used the native perennial forb Achyranthes bidentata and the invasive annual forb Amaranthus spinosus as focal species. We grew the two species with and without competition with each other. This setup was further combined with a treatment involving the addition of polyethylene (PE). We then testd the effects of aqueous extract on seed germination and seedling growth for five invasive and five native species. Subsequently, metabolomic analysis was conducted on the aqueous extracts, in which significant allelopathic effects were observed on test species.Results and discussionThe presence of PE microplastics enhanced the biomass of both Achyranthes and Amaranthus under competitive and non-competitive growth conditions. Furthermore, PE microplastics were found to induce a negative allelopathic effect for the native plant Achyranthes on co-occurring plants, which appeared to be mediated through changes in leaf chemistry. Bisdemethoxycurcumin, ethylparaben, salicin 6’-sulfate and 5-hydroxy-3’,4’,7-trimethoxyflavone glucoside were proven important compounds for allelopathic enhancement. Overall, these results suggest that microplastic pollution has the capability to influence the co-existence of invasive and native plants by altering their allelopathic potential. This insight into the interactions between microplastics and plant allelopathy provides a novel perspective on how microplastic pollution could modify plant species interactions and ecosystem dynamics. Future studies could aim to answer how microplastics might affect plant root exudates and whether this process would mediate biological invasion.

Modeling the seasonal wildfire cycle and its possible effects on the distribution of focal species in Kermanshah Province, western Iran.

Predicting environmental disturbances and evaluating their potential impacts on the habitats of various plant and animal species is a suitable strategy for guiding conservation efforts. Wildfires are a type of disturbance that can affect many aspects of an ecosystem and its species. Therefore, through the integration of spatial models and species distribution models (SDMs), we can make informed predictions of the occurrence of such phenomena and their potential impacts. This study focused on five focal species, namely, the brown bear (Ursus arctos), wild goat (Capra aegagrus), wild sheep (Ovis orientalis), wildcat (Felis silvestris), and striped hyena (Hyaena hyaena). This study used MODIS active fire data and ensemble machine learning methods to model the risk of wildfire occurrence in 2023 for spring, summer, and autumn separately. This study also investigated the suitability of habitats for focal species via SDMs. The predicted probability maps for wildfire risk and habitat suitability were converted to binary values via the true skill statistic (TSS) threshold. The overlap of the habitat suitability map and wildfire occurrence areas was analyzed via GAP analysis. The area prone to fire in spring, summer and winter is equal to 9077.32; 10,199.83 and 13,723.49 KM2 were calculated, which indicates an increase in wildfire risk. Proximity to roads is one of the most important factors affecting the possible effects of wildfires in all seasons. Most fire occurrences are concentrated on agricultural lands, which, when integrated with other land use types, have wildfire potential in all seasons. The use of fire to destroy agricultural residues is a critical factor in the occurrence of wildfires. The distribution range of each focal species is considered the most important component of fire susceptibility. Hence, the suitable habitat for Hyaena hyaena in spring, summer, and autumn, with areas of 5.257, 5.856, and 6.889 km2 respectively, is the most affected by the possibility of fire. In contrast, these areas have the lowest values for Ovis orientalis, with 162, 127, and 396 km2 respectively. Therefore, species that are dependent on human-based ecosystems have the highest vulnerability to wildfire. Conservation efforts should focus on familiarizing farmers with methods of destroying agricultural residues as well as the consequences of intentional fires. The findings of this study can be used to mitigate the negative impacts of wildfire and protect the habitat of focal species.