Increased Germination Rate Research Articles

A pearl millet plasma membrane protein, PgPM19, facilitates seed germination through the negative regulation of abscisic acid-associated genes under salinity stress in Arabidopsis thaliana.

The pearl millet gene PgPM19 inhibits seed dormancy by negatively regulating the ABA biosynthesis and ABA signaling pathways in response to salinity stress in Arabidopsis. Abscisic acid (ABA) plays a pivotal role in orchestrating plant stress responses and development. However, how the ABA signal is transmitted in response to stresses remains primarily uncertain, particularly in monocotyledonous plants. In this study, PgPM19, a gene whose expression is induced by drought, salinity, heat, and ABA in both leaf and root tissues, was isolated from pearl millet. The expression of PgPM19 in yeast cells did not influence their growth when subjected to mannitol, sorbitol, or NaCl stress. However, Arabidopsis plants overexpressing PgPM19 (PgPM19_OE plants) exhibited increased germination rates, greater fresh weights and longer roots under salinity stress during germination, compared to wild-type (WT) plants. Conversely, the pm19L1 (SALK_075435) mutant, featuring a transfer DNA insertion in a closely related PgPM19 homolog (AT1G04560) in Arabidopsis, demonstrated reduced germination rates and smaller fresh weights under salinity-stressed condition than did WT and PgPM19_OE plants. A pivotal ABA biosynthesis gene, NCED3, ABA signaling pathway genes, such as PYL6 and SnRK2.7, alongside downstream ABI genes and stress-responsive genes RAB28 and RD29, were downregulated in PgPM19_OE plants, as evidenced by both transcriptome analysis and quantitative reverse transcription-PCR. These findings raise the possibility that PgPM19 is involved in regulating seed germination by mediating ABA biosynthesis and signaling pathway in response to salinity stress in Arabidopsis. This study contributes to a better understanding of PgPM19 in response to salinity stress and establishes a foundation for unraveling the crosstalk of stress responses and ABA in Arabidopsis and other plant species.

An Artemisia Sphaerocephala Krash gum/acrylic acid-based novel eco-friendly superabsorbent polymer: Its synthesis and properties promoting seed germination

An affordable, eco-friendly, and salt-tolerant superabsorbent polymer (SAP) has been synthesised from Artemisia sphaerocephala Krasch gum (ASKG), a naturally hydrophilic heteropolysaccharide extracted from the seeds of Artemisia sphaerocephala and acrylic acid (AA) through free-radical polymerisation (ASKG/AA-SAP) using ammonium persulfate (APS) as the initiator and N, N´-methylenebisacrylamide (MBA) as the cross-linker. Morphological and thermal analyses confirmed that ASKG/AA-SAP showed a uniformly interconnected porous structure with a high thermal stability and a gradual decomposition rate. Notably, ASKG/AA-SAP demonstrated exceptional water absorbency, reaching maximum values of 1250g·g-1 in distilled water and 152g·g-1 in a 0.9wt% NaCl solution. Work on relevant parameters related to SAP, viz water absorbency, water retention, and reusability under different influencing factors has been carried out, as also the swelling capacity, salt tolerance, and the ability to withstand a wide range of pH values (4-12) and temperatures (5-55°C). Furthermore, ASKG/AA-SAP has also demonstrated water retention, viz maintaining a rate of 34.19% after 5h in distilled water, which are superior to those of other SAPS tested. Interestingly, the application of ASKG/AA-SAP has resulted in a substantial improvement in seed germination of desert plant, as evidenced by an increase in germination rate and germination energy of Hedysarum scoparium by 58.66% and 35.71%, respectively, compared to the control group. ASKG/AA-SAP, therefore, holds excellent potential for application in agri-forestry production and afforestation works within arid and semi-arid regions.

Characterization of four Acidovorax phages and their potential in phage biocontrol for lamb's lettuce seed decontamination.

Bacterial black spot, caused by Acidovorax valerianellae, is responsible for significant yield losses in lamb's lettuce (Valerianella locusta) in many producing countries, especially Europe. Currently, no resistant varieties of V. locusta are available that effectively control the disease under field conditions. Bacteriophage-based biocontrol has been suggested as a sustainable and natural alternative strategy to combat bacterial pathogens. In this study, novel phages infecting A. valerianellae and Acidovorax cattleyae, Alfacinha1, Alfacinha3, Acica, and Aval, were isolated and characterized. Based on comparative genomics, these phages represent three new phage genera. Aval and Acica phages revealed genomic features characteristic of temperate lifestyle, encoding toxins likely associated with lysogenic conversion, which contrasts with Alfacinha1 and Alfacinha3. The latter was selected for application as a biocontrol agent during seed steeping. This phage reaches an 87% reduction in the A. valerianellae concentration on artificially infested seeds. Importantly, this reduction results in an increased germination rate from 58.9% to 93.3%. Moreover, the infected seedlings had a dramatic reduction in vigor index after 22 days of growth, whereas the phage-treated ones had a vigor index similar to the negative control, reinforcing the ability of bacteriophages to effectively reduce disease progression. We further evaluated the impact of lipopolysaccharides in phage suspensions on the development of seedlings. Here, we demonstrated that the presence of lipopolysaccharides do have an impact on seedling development, significantly reducing the number of roots developed. This study shows how genomic analyses and tailored bioassays represent an essential route to ensure safe phage application and demonstrates the potential of a phage-based biocontrol strategy against A. valerianellae.IMPORTANCEBacteria continue to globally cause serious damage to a variety of crops. One example is a bacterial black spot of lamb's lettuce caused by Acidovorax valerianellae. It has spread across Europe, resulting in economic losses of at least 10% in tonnage annually. Faced with the inefficiency of conventional control methods, an alternative and sustainable strategy based on the use of bacteriophages was pursued in this study. We present for the first time the isolation and characterization of A. valerianellae-specific phages. Moreover, we assessed their biocontrol potential in seed decontamination since the disease primarily spreads from seeds to seedlings. Interestingly, seed treatment with one of our phages reaches an 87% reduction in bacterial concentration. More importantly, this reduction results in an increased germination rate from 58.9% to 93.3%. Finally, our study demonstrated for the first time the need for removing endotoxins from phage suspensions as they impact plant development when used as a biocontrol agent.

Influence of Sporulation Temperature on Germination and Growth of B. weihenstephanensis Strains in Specific Nutrients and in an Extended Shelf-Life Refrigerated Matrix Under Commercial Pasteurization and Storage Conditions.

Extended shelf-life (ESL) refrigerated ready-to-eat foods are thermally pasteurized to ensure food safety and stability. However, surviving psychrotrophic Bacillus cereus spores can still pose a challenge. Studies predicting their behavior often overlook sporulation conditions. This study investigated the effect of sporulation temperature on germination of three Bacillus weihenstephanensis strains in specific nutrients (inosine and/or amino acids) with or without prior heat activation (80 °C, 10 min). Sporulation temperature variably affected germination, with stronger effects in moderately responsive strains and nutrients. Heat activation strongly stimulated germination, particularly in nutrients with poorer responses, mitigating differences induced by sporulation temperature. The influence of sporulation temperature on germination and growth in an ESL matrix at refrigeration temperatures (4 °C or 8 °C) in vacuum packaging after heat activation or commercial pasteurization (90 °C, 10 min) was also studied. The latter treatment increased germination rates of surviving spores; however, some strains suffered damage and lost viability upon germination at 4 °C but recovered and grew at 8 °C. These findings highlight the need to account for variability in spore recovery and outgrowth during quantitative risk assessments for psychrotrophic B. cereus in ESL foods.

Gibberellic Acid and Abscisic Acid Effects on Germination Across Arabidopsis Genotypes: Confirmation of Compound Identity and Genotypic Responses

It is well known that plant growth depends on the interaction of auxin and hormones, but whether different hormones have different effects on seed growth in different varieties is not fully understood. This study used a controlled experimental setup in which seeds from three different genotypes (assumed to be wild-type, abscisic acid (ABA) insensitive, and gibberellic acid (GA) deficient) were exposed to treatments of these compounds (labeled compounds A and B), as well as a control treatment using ethanol. Our results confirm the identities of Compound A as gibberellic acid and Compound B as abscisic acid through their consistent effects on seed germination. Gibberellic acid (Compound A) significantly enhanced germination across all genotypes. With the help of Gibberellic acid, GA-deficient genotype also showed a dramatic increase in germination rates which suggested a compensatory effect. Conversely, abscisic acid (Compound B) markedly inhibited germination, with the most pronounced effect observed in the wild-type genotype. The ABA-insensitive genotype demonstrated reduced susceptibility to Compound B, supporting its phenotypic characterization. The study highlights the key antagonistic role of gibberellic acid and abscisic acid in seed germination, providing valuable insights into defining genotypic-phenotypic interactions in plant responses to environmental and chemical signals.

Identification and Disinfection Treatment Technology of a New Guangdong Choy Sum Disease

Seed-borne diseases cause significant economic losses in modern agriculture. The use of large amounts of chemical pesticides to control seed-borne diseases also results in negative consequences such as environmental pollution and pesticide residue in agricultural products. This has generated great interest among scholars in detecting and controlling seed-borne diseases. This study screened and isolated a new pathogenic fungus, Penicillium decumbens, from three Guangdong choy sum varieties. The virulence test showed that it inhibited seed germination rate by 40% and germination vigor by 50%. The conventional seed disinfectants (Thiram WP) did not completely eliminate the pathogenic bacteria. A comparative study of nine seed disinfectants revealed that 50% Carbendazim WP, 80% Thiram WP, 15% Carbendazim+15% Thiram WP, and 45% Prochloraz EW exhibited significant fungicidal effects against Penicillium decumbents infection in Guangdong choy sum seeds. Based on comprehensive indicators including germination rate, germination vigor, and root length after disinfection treatment, the most effective disinfectant was 45% Prochloraz EW with a sterilization effect of 100%, an increase in germination vigor by 37.5%, and an increase in germination rate by 27.9%.

The seed endophytic microbe Microbacterium testaceum M15 enhances the cold tolerance and growth of rice (Oryza sativa L.)

The potential of seed endophytic microbes to enhance plant growth and resilience is well recognized, yet their role in alleviating cold stress in rice remains underexplored due to the complexity of these microbial communities. In this study, we investigated the diversity of seed endophytic microbes in two rice varieties, the cold-sensitive CB9 and the cold-tolerant JG117. Our results revealed significant differences in the abundance of Microbacteriaceae, with JG117 exhibiting a higher abundance under both cold stress and room temperature conditions compared to CB9. Further analysis led to the identification of a specific cold-tolerant microbe, Microbacterium testaceum M15, in JG117 seeds. M15-inoculated CB9 plants showed enhanced growth and cold tolerance, with a germination rate increase from 40 % to 56.67 % at 14℃ and a survival rate under cold stress (4℃) doubling from 22.67 % to 66.67 %. Additionally, M15 significantly boosted chlorophyll content by over 30 %, increased total protein by 16.31 %, reduced malondialdehyde (MDA) levels by 37.76 %, and increased catalase activity by 26.15 %. Overall, our study highlights the potential of beneficial endophytic microbes like M. testaceum M15 in improving cold tolerance in rice, which could have implications for sustainable agricultural practices and increased crop productivity in cold-prone regions.

Propagation and growth of Paspalum carajasense: a threatened Amazonian canga grass

Paspalum carajasense, an endemic and endangered annual grass found in the canga ecosystems of Serra dos Carajás, Brazil, lacks adequate propagation and conservation data. We assessed its germination and growth in various substrates to support conservation and mineland rehabilitation purposes. Seed germination tests involved soaking in water for 24 h and two KNO3 concentrations (2.5% and 5.0%). Seedlings were grown for 100 days on canga topsoil, mining waste substrate, and a commercial organic substrate. Mining substrates received 0%, 50%, and 100% of Carajás revegetation nutrients due to low fertility. Paspalum carajasense can be sexually propagated and pregermination treatments did not increase germination rates (14%). Seedlings were able to grow in all substrates and showed zero mortality. Plants in fertilized substrates showed similar growth to that on canga topsoil, with significant changes in root and leaf traits. In organic substrates, plants accumulated a larger amount of biomass and produced substantial amounts of seeds with higher germination rates, supporting the feasibility of ex situ cultivation. Therefore, our study provides essential information for the propagation and ex situ cultivation of a rare species of canga ecosystems and highlights the possibility of reconciling the conservation of P. carajasense with mineland rehabilitation.

Adaptation to Environmental Stressors Conferred by Gene Copy Number Variation in Herbicide Resistant Amaranthus palmeri

Many rampant agricultural weeds have been found to contain gene copy number variation, a genetic adaptation that can facilitate the evolution of stress resistance. Amaranthus palmeri is a highly competitive and problematic agricultural weed in the United States which continues to naturalize, spreading northward to Canada. A.palmeri has gained attention due to its rapid evolution of herbicide resistance— a mechanism conferred by gene copy number variation of EPSPS. Researchers hypothesize that this gene is contained within an amplicon alongside other stress tolerance related genes. This raises the question of whether increased EPSPS gene copy number is associated with higher tolerance to environmental stressors, beyond herbicide stress. To prepare for addressing this hypothesis, I conducted a pilot project testing the ideal conditions for germination of A.palmeri. I planted 200 seeds divided between greenhouse and growth chamber environments. Many seeds benefit from a period of cold as a signal to break dormancy, thus, each category was further divided into two treatments: control and cold stratified (seeds were incubated in a –23 cold room for a week). I was interested in whether the increased consistency of temperature, light intensity, and photoperiod provided by a growth chamber, relative to a greenhouse, would increase germination rates. Results indicate that greenhouse grown seedlings had a 71% germination rate and within each treatment, 86% of cold stratified plants germinated while only 56% of the control group germinated. Whereas in the growth chamber, surprisingly only 26% of plants germinated with a breakdown of 22% cold stratified and 30% control. Thus, to germinate enough plants for a large-scale experiment, I chose to cold stratify seeds and grow them in the greenhouse for my undergraduate thesis. In this common garden experiment, I am currently growing 500 plants which will be divided into four stress treatment categories: control, salinity, drought, and salinity x drought. Using phenotypic measurements and digital droplet PCR (ddPCR) to quantify EPSPS gene copy number, I will test for a possible association between plants with a higher tolerance to these simulated environmental stressors and the presence of increased EPSPS gene copy number.

Effect of hyaluronic acid-stabilized silver nanoparticles on lettuce (Lactuca sativa L.) seed germination

Nanotechnology has brought significant advancements to agriculture through the development of engineered nanomaterials (ENPs). Silver nanoparticles (AgNPs) capped with polysaccharides have been applied in agricultural diagnostics, crop pest management, and seed priming. Hyaluronic acid (HA), a natural polysaccharide with bactericidal properties, has been considered a growth regulator for plant tissues and an inducer of systemic resistance against plant diseases. Additionally, HA has been employed as a stabilizing agent for AgNPs. This study investigated the synthesis and effects of hyaluronic acid-stabilized silver nanoparticles (HA-AgNPs) as a seed priming agent on lettuce (Lactuca sativa L.) seed germination. HA-AgNPs were characterized using several techniques, exhibiting spherical morphology and good colloidal stability. Germination assays conducted with 0.1, 0.04, and 0.02 g/L of HA-AgNPs showed a concentration-dependent reduction in seed germination. Conversely, lower concentrations of HA-AgNPs significantly increased germination rates, survival, tolerance indices, and seed water absorption compared to silver ions (Ag+). SEM/EDS indicated more significant potential for HA-AgNPs internalization compared to Ag+. Therefore, these findings are innovative and open new avenues for understanding the impact of Ag+ and HA-AgNPs on seed germination.

Application of biostimulants in agriculture: Effects on plant growth and yield

The study aimed to evaluate the effectiveness of the use of biostimulants, such as humic acid preparation, Seaweed algae extract and microbial preparation BaikalEM, on plant growth and yield. The impact of biostimulants on plant development and crop yields was studied on sugar beet (Beta vulgaris) and maize (Zea mays). To achieve this goal, field studies were conducted to compare different biostimulants in terms of germination and yield (total crop weight, weight of a single fruit, sugar, starch and protein content). The study was conducted in April-August 2023 in the Sumy district of the Sumy region. Standard agronomic methods, including soil cultivation, measurement of plant growth and yield parameters, and statistical processing of the data were used in the study. The results showed that humic acids and algae extract, when applied separately, provided the highest seed germination and yield. Among all the variants of combined application, the most significant increase in germination rates for beetroot was provided by treatment with a combination of Seaweed and Baikal-EM – 91.7%. For maize, Seaweed with humic acids and Seaweed with Baikal-EM are 92% each. The combination of Seaweed and humic acids had the best effect on the yield of both crops: 460.9 c/ha for beetroot (compared to 325 c/ha without treatment) and 61 c/ha for corn (41.5 c/ha without treatment). The microbial preparation Baikal also demonstrated a positive effect, but its results were lower, and it proved effective in combination with humic acids. The results obtained indicate the feasibility of using humic acids and algae extract to increase plant productivity, while Baikal can be useful for improving the general condition of soil and plants in combination with other fertilisers

Enhancing drought stress tolerance and growth promotion in chiltepin pepper (Capsicum annuum var. glabriusculum) through native Bacillus spp.

The drought can cause a decrease in food production and loss of biodiversity. In northern Mexico, an arid region, the chiltepin grows as a semi-domesticated crop that has been affected in its productivity and yield. An alternative to mitigate the effect of drought and aid in its conservation could be using Plant Growth-Promoting Bacteria (PGPB). The present study evaluated the capacity of native Bacillus spp., isolated from arid soils, as PGPBs and drought stress tolerance inducers in chiltepin under controlled conditions. Chiltepin seeds and seedlings were inoculated with native strains of Bacillus spp. isolated from arid soils, evaluating germination, vegetative, and drought stress tolerance parameters. The PGPBs improved vegetative parameters such as height, stem diameter, root length, and slenderness index in vitro. B. cereus (Bc25-7) improved in vitro survival of stressed seedlings by 68% at −1.02 MPa. Under greenhouse conditions, seedlings treated with PGPBs exhibited increases in root length (9.6%), stem diameter (13.68%), leaf fresh weight (69.87%), and chlorophyll content (38.15%). Bc25-7 alleviated severe water stress symptoms (7 days of water retention stress), and isolates B. thuringiensis (Bt24-4) and B. cereus (Bc25-7, and Bc30-2) increased Relative Water Content (RWC) by 51%. Additionally, the treated seeds showed improved germination parameters with a 46.42% increase in Germination Rate (GR). These findings suggest that using PGPBs could be an alternative to mitigate the effect of drought on chiltepin.

Investigating the effects of nutrition priming on germination indicators, the concentration of elements in seeds, and growth rate in the initial stages of Persian clover (Trifolium resupinatum L.)

Insufficient stand establishment and low seedling development of Persian Clover (Trifolium resupinatum L.) are major problems. A study involving laboratory and greenhouse conditions was conducted to determine seed priming effects on germination rate and growth index. To determine the best time for seed priming, pre-experiments were performed for 1, 2, 4, 8, 16, and 32 h. Afterward, germination parameters were measured in the laboratory by 16 different nutrient priming (B, Fe, Mg, Ca, and a combination of these) and two priming duration (one and two hours selected from pre-experiment). The greenhouse experiment was conducted to evaluate the ability of nutrition priming with B + Fe + Mg + Ca to compensate for the deficiency of these soil nutrients where growth index (CGR and LAI) and SPAD index were measured in four treatments (control, nutrition priming, Nitrogen as starter fertilizers and nutrition priming + Nitrogen as a starter). Laboratory data for pre-experiment showed that one and two hours of hydro priming was suitable for clover seed. One hour of hydro priming led to a significant increase in germination rate (20%), length (26%) and weight (10%) vigor. Control, Priming with B + Ca, B + Mg and B + Mg + Ca led to highest germination percentage (≈96%), also B + Ca caused the highest length and weight vigor (61 and 2.22). The greenhouse experiment data illustrated that nutrition priming increased by about 10% in TDW, 23% in LAI, and 4% in SPAD index in the first 40 days of early growth stages, but increased by 27% in CGR, 47% in LAI, and 10% in SPAD index if combined with the application of nitrogen as a starter fertilizer.

Transformative impact of atmospheric cold plasma on mung bean seeds: Unveiling surface characteristics, physicochemical alterations, and enhanced germination potential

This work investigates the impact of a new geometry Atmospheric Cold-Plasma (ACP) system on mung bean (Vigna radiata) seed germination and seedling growth. Plasma is produced using a bipolar pulse power source, providing superior control of the generated species. A substantial increase in germination rates (86.67%–91.67%) and optimal seedling growth after 40 s of treatment is reported. The functional and morphological features have shown improvements. Plasma treatment significantly increases the specific surface area (7.695 m2/g) and total pore volume (0.007 cc/g) of the seeds compared to the control (2.214 m2/g and 0.001 cc/g, respectively), suggesting potential enhancements in water absorption and nutrient exchange. Radicle growth stimulation is also observed without alterations in the seed’s chemical structure. These findings highlight the potential of the ACP system for enhancing mung bean sprout germination and seedling development, which is helpful for agriculture applications.

Development, characterization, and evaluation of Zn-SA-chitosan bionanoconjugates on wheat seed, experiencing chilling stress during germination

This study aimed to develop and characterize the chitosan bionanoconjugates (BNCs) loaded with zinc (Zn) and salicylic acid (SA) and test their efficacy on wheat seed exposed to chilling stress. BNCs developed were spherical (480 ± 6.0 nm), porous, and positively charged (+25.2 ± 2.4 mV) with regulated nutrient release properties. They possessed complexation efficiency of 78.4 and 58.9 % for Zn, and SA respectively. BET analysis further confirmed a surface area of 12.04 m2/g. Release kinetics substantiated the release rates of Zn and SA, as 0.579 and 0.559 % per hour, along with a half-life of 119.7 and 124.0 h, respectively. BNCs positively affected the germination potential of wheat seeds under chilling stress as observed by significantly (p < 0.05) reduced mean emergence time (18 %), and increased germination rate (22 %), compared to the control. Higher activities of reserve mobilizing enzymes (α-amylase- 6.5 folds, protease −10.2 folds) as well as faster reserve mobilization of starch (64.4 %) and protein (63.5 %) molecules were also observed. The application further led to increased levels of the antioxidant enzymes (SOD and CAT) and reduced oxidative damage (MDA and H2O2). Thus, it is inferred that the developed BNCs could help substantially improve the germination and reserve mobilization potential, thereby increasing the crop yield.

Composites of sodium alginate based - Functional materials towards sustainable adsorption of benzene phenol derivatives - Bisphenol A/Triclosan

The present study evaluates the adsorption efficiency of low-cost carbonaceous adsorbents as fly ash (FA), saw dust biochar (SDB) (untreated and alkali - treated), live/dead pulverized white rot fungus Hypocrea lixii biomass encapsulated in sodium alginate (SA) against the commercially available activated carbon (AC) and graphene oxide (GO) SA beads for removal of benzene phenol derivatives - Bisphenol A (BPA)/triclosan (TCS). Amongst bi - and tri - composites SA beads, tri-composite beads comprising of untreated flyash - dead fungal biomass - sodium alginate (UFA - DB - SA) showed at par results with commercial composite beads. The tri - composite beads with point zero charge (Ppzc) of 6.2 was characterized using FTIR, XRD, surface area BET and SEM-EDX. The batch adsorption using tri - composite beads revealed removal of 93% BPA with adsorption capacity of 16.6 mg/g (pH 6) and 83.72% TCS with adsorption capacity of 14.23 mg/g (pH 5), respectively at 50 ppm initial concentration with 6 % adsorbent dose in 5 h. Freundlich isotherm favoring multilayered adsorption provided a better fit with r2 of 0.9674 for BPA and 0.9605 for TCS respectively. Intraparticle diffusion model showed adsorption of BPA/TCS molecules to follow pseudo - second order kinetics with boundary layer diffusion governed by first step of fast adsorption and intraparticle diffusion within pores by second slow adsorption step. Thermodynamic parameters (ΔH°, ΔS°, ΔG°) revealed adsorption process as exothermic, orderly and spontaneous. Methanol showed better desorbing efficiency leading to five cycles reusability. The phytotoxicity assay revealed increased germination rate of mung bean (Vigna radiata) seeds, sprinkled with post adsorbed treated water (0 h, 5 h and 7 h) initially spiked with 50 ppm BPA/TCS. Overall, UFA - DB - SA tri - composite beads provides a cost effective and eco - friendly matrix for effective removal of hydrophobic recalcitrant compounds.

RhMED15a-like, a subunit of the Mediator complex, is involved in the drought stress response in Rosa hybrida

BackgroundRose (Rosa hybrida) is a globally recognized ornamental plant whose growth and distribution are strongly limited by drought stress. The role of Mediator, a multiprotein complex crucial for RNA polymerase II-driven transcription, has been elucidated in drought stress responses in plants. However, its physiological function and regulatory mechanism in horticultural crop species remain elusive.ResultsIn this study, we identified a Tail module subunit of Mediator, RhMED15a-like, in rose. Drought stress, as well as treatment with methyl jasmonate (MeJA) and abscisic acid (ABA), significantly suppressed the transcript level of RhMED15a-like. Overexpressing RhMED15a-like markedly bolstered the osmotic stress tolerance of Arabidopsis, as evidenced by increased germination rate, root length, and fresh weight. In contrast, the silencing of RhMED15a-like through virus induced gene silencing in rose resulted in elevated malondialdehyde accumulation, exacerbated leaf wilting, reduced survival rate, and downregulated expression of drought-responsive genes during drought stress. Additionally, using RNA-seq, we identified 972 differentially expressed genes (DEGs) between tobacco rattle virus (TRV)-RhMED15a-like plants and TRV controls. Gene Ontology (GO) analysis revealed that some DEGs were predominantly associated with terms related to the oxidative stress response, such as ‘response to reactive oxygen species’ and ‘peroxisome’. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment highlighted pathways related to ‘plant hormone signal transduction’, in which the majority of DEGs in the jasmonate (JA) and ABA signalling pathways were induced in TRV-RhMED15a-like plants.ConclusionOur findings underscore the pivotal role of the Mediator subunit RhMED15a-like in the ability of rose to withstand drought stress, probably by controlling the transcript levels of drought-responsive genes and signalling pathway elements of stress-related hormones, providing a solid foundation for future research into the molecular mechanisms underlying drought tolerance in rose.

Biological Control of Pseudomonas syringae in Tomato Using Filtrates and Extracts Produced by Alternaria leptinellae

Endophytic fungi offer promising alternatives for sustainable plant disease management strategies, often through the production of bioactive secondary metabolites. This study investigated the biocontrol potential of filtrates and extracts, produced under controlled conditions, from Alternaria leptinellae E138 against Pseudomonas syringae in tomato plants under greenhouse conditions. To understand the main mechanisms involved in biocontrol, the direct inhibition of bacterial growth and disruption of quorum sensing activity caused by metabolites were studied in vitro, as well as indirect mechanisms, such as their capacity to produce phytohormone-like substances, nutrient mobilization, and antioxidant activity, which can enhance plant growth and fitness. Moreover, a mass spectrometry analysis was used to tentatively identify the secondary metabolites present in the extract with antimicrobial properties, which could explain the biocontrol effects observed. Mycopriming assays, involving the direct treatment of tomato seeds with the fungal A. leptinellae E138 extracts, produced increased germination rates and seedling vigor in tomato seeds. As another treatment, postemergence application of the extracts in greenhouse conditions significantly improved plant health and resulted in a 41% decrease in disease severity. Overall, this study underscores the potential of A. leptinellae E138 extract as a plant growth promoter with biocontrol capabilities, offering promising avenues for sustainable plant disease management.

Effects of Nano-Silica and Multi-Walled Carbon Nanotubes on Grape Seedlings under Salt Stress

To improve the salt tolerance of grape seeds and seedlings under salt stress, this study was conducted including two control groups (CK, S) and five experimental groups (S + Si40, S + Si60, S + Si80, S + C90, S + Si40 + C90), and the physiological characteristics of grape seed germination and seedlings were studied using 40, 60, and 80 μg/mL of nano-silica treatments and by mixing 40 μg/mL of nano-silica with 90 μg/mL of multi-walled carbon nanotubes (MWCNTs), respectively. The combined treatment of 40 μg/mL nano-silica and 90 μg/mL MWCNTs resulted in the best rate of growth in grape seeds and root length and an increased germination rate when compared with the other concentrations. The combined treatment reduced the MDA content in the grape seedling leaves and increased the activities of superoxide (SOD), peroxidase (POD), catalase (CAT), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), ascorbate peroxidase (APX), glutathione-s-transferase (GT), and glutathione reductase (GR). In addition, the scavenging activity of DPPH· was also maintained by the combined treatment. In conclusion, a combined treatment with 40 μg/mL nano-silica and 90 μg/mL MWCNTs significantly increased the reduction capacity through the direct and indirect antioxidant systems (AsA-GSH cycle) and maintained a high antioxidant capacity of grape seedlings under salt stress.

Impact of pulsed electric field treatment on barley germination for malting

The malting process takes one week to steep, germinate, and kiln barley to make malt. Making quality malt is critically important to achieve the desired attributes of the finished beer, and the process is time-intensive and costly. Malt quality is assessed by indicators including β-glucan quantity, α-amylase activity, Free Amino Nitrogen (FAN) content, and overall extract concentration in the finished malt. Here, we report Pulsed Electric Field (PEF) treatment of barley to accelerate malt production. A small-scale trial of 250 g to 1.00 kg barley, was evaluated for germination at two PEF treatment conditions, generically referred to as “low” and “high”, that resulted in increased barley rootlet length during germination of 1.3 mm longer than was observed for the control. Large-scale trials of 1.00 kg–3.00 kg barley, resulted in an increase in germination rate and a decrease of β-glucan concentration in the PEF treated barley. Micromalted barley using PEF parameters of 1.0 kV/cm and 15.0 kJ/kg displayed a reduction in β-glucan concentration by 38%, and increase in malt extract by 1.5%, FAN by 6.2%, and α-amylase by 8.4%, supporting the hypothesis that PEF treated barley generates more and better malt, leading to greater efficiency in the beer making process.