Root-knot nematodes (RKN) are globally distributed and highly pathogenic. By determining the threshold at which damage occurs, we can create effective measures to protect plants from nematodes. In our study, we investigated the impact of ten initial population densities (Pi-log series) of M. javanica, i.e., 0, 2.38, 2.68, 2.98, 3.28, 3.58, 3.88, 4.18, 4.48 and 4.78 juveniles (J2) g(-1) soil on tomato cv. S22 plants in pots. The graphical estimation of yield losses caused by RKN was calculated using Seinhorst's yield loss model based on the relationship between the RKN population and damage to tomato plants. The relationship between initial nematode population density (Pi) and plant yield was analyzed using Seinhorst's model, where T is the tolerance limit, m is the minimum yield, and z is a constant describing yield decline. This allowed us to determine the threshold at which nematode infestation significantly reduces tomato growth. Seinhorst's model, y = m + (1-m) 0.95(Pi/T-1) for Pi > T; y = 1 for Pi <= T for RKN, was fitted to the data of shoot length and fresh weight of infected and uninoculated control plants to estimate the damage threshold level. The impact of M. javanica on plant physiological parameters, including chlorophyll content, carotenoid and nitrate reductase activity, root-gall formation, and disease incidence, was also determined in this study. The tolerance limits for relative tomato shoot length and fresh weight were 3.34 J2 of M. javanica g(-1) soil. The minimum relative values (y(m)) for shoot length and fresh weights were 0.39 and 0.42, respectively. We found that the damage threshold level was between 3.28 and 3.58. The root galls index, nematode population and reproduction factors were 3.75, 113 and 29.42, respectively, at an initial population density (Pi) of 3.58 J2 g(-1) soil. The chlorophyll (0.43 mg g(-1)), carotenoids (0.06 mg g(-1)) and nitrate reductase activity (0.21 mu mol min(-1) g(-1)). Our study highlights the importance of the accurate estimation of damage thresholds, which can guide timely and effective nematode management strategies.

Rhizoctonia solani is a significant soil-borne pathogenic fungus that poses a significant threat to the economically important agricultural crops. 4-(Diethylamino)salicylaldehyde (DSA) is a secondary metabolite produced by Streptomyces sp. KN37, which has antifungal activity, meanwhile its inhibitory mechanism is still unclear. In this study, we explored the antifungal efficacy of DSA and its potential mechanism of inhibiting R. solani. It was found that DSA exhibited significant antifungal activity against six tested plant pathogenic fungi, with R. solani being the most sensitive (EC50 = 26.904 mu g/mL). Notably, DSA effectively reduced the mycelial mass and inhibited sclerotia germination, demonstrating a good control efficacy of cucumber damping-off disease. Morphological observation showed that DSA significantly disrupted the shape and ultrastructure of the mycelium. Transcriptomic and metabolomic analyses revealed that DSA impacted the integrity of the cell membrane, redox processes, and energy metabolism in R. solani. The results of fluorescence staining, relative conductivity, H2O2 content, and antioxidant enzyme activity showed that the accumulation of ROS in hypha cells after DSA treatment possibly resulted in damage to cell membrane integrity. Furthermore, the reduction in ATP content, along with decreased ATPase and citrate synthase activity, indicates that energy production may be inhibited. Molecular docking analysis further showed that DSA may competitively inhibit citrate synthase, thereby inhibiting cell energy production and ultimately inducing apoptosis. Our study provides new insights into the potential mechanism by which DSA inhibits the mycelial growth of R. solani.

It has not been known how immune responses in soil invertebrates occur against microplastics (MPs). This study aims to investigate the effects of MPs on endocytosis, including phagocytosis and pinocytosis, of immune cells of soil invertebrates in the soil ecosystem in the process of bacterial infection. We employed polystyrene micro- plastics (similar to 1 mu m PS MPs) to treat earthworm Eisenia andrei during the infection of Escherichia coli for in vitro (1, 5, 10, and 50 mg/L) and in vivo (1, 10, and 1000 mg/kg dry soil) assays. The results of in vitro migration assay revealed that MPs caused inhibitory effects on the phagocytosis, pinocytosis and oxidative stress in coelomocytes. Soil bioassay also confirmed that endocytosis of coelomocytes and mitochondrial damages in the intestinal epithelium were significantly altered in the polluted soil with MPs. Thus, MPs induced adverse effects to inhibit bacterial endocytosis, which may disturb the immune system of soil invertebrates. This study is the first report on the inhibition of phagocytosis in the soil invertebrates by MPs. These findings contribute to understanding the response of soil invertebrates, which play important roles in the soil food web with cellular level towards microplastic pollution in soil.

Throughout history, plant diseases have posed significant challenges to agricultural progress, driven by both abiotic and biotic factors. Abiotic factors include wind, salt damage, freezing, girdling roots and compacted soil, while biotic factors encompass bacteria, nematodes, fungi and viruses. Plants have evolved diverse defense strategies to counter pathogen attacks, one of which involves chitinases, a subset of pathogenesis-related proteins. Chitinases are hydrolytic enzymes that degrade chitin, a high-molecular-weight linear polymer of N-acetylD-glucosamine, which is a crucial component of fungal cell walls and septa. These enzymes are produced by a wide range of organisms, including plants, animals, insects, fungi and microorganisms. In plants, chitinases are strongly expressed under pathogenic stress, primarily targeting fungal pathogens by breaking down their cell walls. They also contribute to cell wall remodeling and degradation during growth and defense processes. Numerous studies have demonstrated that the antifungal activity of chitinases is influenced by the chitin concentration and surface microstructure of different fungal species. Research has highlighted their role in protecting plants like mango, cucumber, rye, tomato, grapevine and other plants from various fungal diseases. These findings underscore the critical role of chitinases in plant defense mechanisms, showcasing their importance in mitigating fungal infections and supporting plant health.

Robusta coffee, a vital cash crop for Vietnamese smallholders, significantly contributes to the national economy. Vietnam is the largest exporter of Robusta coffee, supplying 53% of the global market. However, this success has come at a cost. Decades of intensive Robusta coffee cultivation in Vietnam have led to severe soil acidification and biodiversity loss, favoring soil-borne pathogens. There is a lack of literature analyzing how intensive management causes soil acidification, advances the spread of soilborne pathogens, and the application of soil amendments to address these issues. Therefore, this review explores the causes of acidification, pathogen proliferation, and sustainable amendments like lime and biochar to mitigate these effects. The study synthesizes findings from studies on soil acidification, soil-borne pathogen dynamics, and sustainable soil amendments in Robusta coffee systems. We found that the overuse of nitrogen-based chemical fertilizers to grow coffee is the primary driver of soil acidification, consequently increasing soilborne diseases and the severity of plant diseases. Additionally, the effects of soil amendments as a sustainable solution to reduce soil acidity, enhance soil health, and better control soilborne pathogens. The implementation of sustainable coffee farming systems is strongly recommended to meet the increased demand for safe and green products worldwide. Locally available resources (lime, biochar, and agricultural wastes) present immediate solutions, but urgent action is required to prevent irreversible damage. However, the effects of amendments significantly vary in field conditions, suggesting that further studies should be conducted to address these challenges and promote sustainability.

The use of chemical pesticides in agriculture leads to the accumulation of harmful compounds in soil and plants that can cause diseases of humans and animals. The biological method of plant protection is a promising alternative to chemical pesticides. The purpose of this study was to analyze the antagonistic activity of the Acinetobacter sp. GET13 strain against common bacterial and fungal pathogens of plant diseases in in vitro and in planta experiments. As a result, the effect of the bacterium on the growth of phytopathogenic bacteria (Clavibacter michiganensis, Erwinia carotovora, Pectobacterium carotovorum and Pseudomonas syringae), as well as phytopathogenic fungi (Helminthosporium sativum, Piricularia oryzae.) that cause serious damage to agriculture, was studied. To confirm the results obtained in these experiments, an in planta experiment was conducted on Phaseolus vulgaris (L.) The effectiveness of Acinetobacter GET13 strain for plant protection against phytopathogens was proved based on the results of taking into account the linear function between weight and volume parameters of plants at the end of the experiment. Therefore, this strain has the potential to create a biological product.

A polyphasic taxonomic approach was conducted to characterize the bacterial strain B22T isolated from the rhizospheric soil of the halophyte Salicornia hispanica. This strain is aerobic, Gram-negative, rod-shaped, catalase and oxidase positive, motile, reduces nitrates and chemoheterotrophic. It is halotolerant, exhibiting optimal growth at 28 degrees C and pH 7.0 in the presence of 0.5-2.5% (w/v) of NaCl. The B22T genome size is 5.7 Mbp, with a G+C content of 60.5 mol%. This strain has the capacity to promote tomato growth by producing siderophores, indole-3-acetic acid and enzymes such as phytase and acid phosphatase. Additionally, strain B22T produces a quorum quenching (QQ) enzyme capable of degrading synthetic N-acylhomoserine lactones (AHLs) as well as those produced by phytopathogens. The interference of plant pathogen communication reduced virulence in tomato fruits and plants. Phylogenetic analysis revealed that the closest relatives of strain B22T was Pseudomonas tehranensis SWRI 196T. The average nucleotide identity values between strain B22T and P. tehranensis SWRI 196T was 95.1% while digital DNA-DNA hybridization values was 64.5% The main cellular fatty acids of strain B22T were C16:0, summed feature 3 (C16:1 omega 7c/C16:1 omega 6c) and summed feature 8 (C18:1 omega 7c/C18:1 omega 6c). The major polar lipids identified were diphosphatidylglycerol and phosphatidylethanolamine, while the predominant respiratory quinone was ubiquinone (Q-9). Based on genomic, phylogenetic and chemotaxonomic data, strain B22T (=CECT 31209; =LMG33902) represents a novel species within the genus Pseudomonas. The name Pseudomonas halotolerans sp. nov. is proposed. Additionally, this study highlights the potential of P. halotolerans as a sustainable biocontrol agent due to its plant growth-promoting activity in tomato plants and its ability to reduce phytopathogen virulence factors, mitigating damage to fruits and plants.

Root-lesion nematodes, particularly Pratylenchus neglectus and P. crenatus (PNC), are widely distributed in New Zealand and cause significant damage to maize roots, reducing crop productivity. Despite their economic importance, no comprehensive assessment of commercial maize hybrids' resistance to PNC has been conducted in the country. Significant variation was observed in the nematode reproduction factor (Rf) and final population (Pf) among hybrids. In Experiment 1 (initial population (Pi) = 1250 PNC kg(-)(1) soil), Rf ranged from 3.1 in hybrid P8500 to 7.1 in hybrid P9127, with Pf values ranging from 3863 to 8903 PNC kg(-)(1) soil + roots in 45 days. In Experiment 2 (Pi = 750 PNC kg(-)(1) soil), Rf ranged from 18.4 in hybrid P1613 to 37.5 in hybrid P8805, with Pf values from 13,784 to 28,426 PNC kg(-)(1) soil + roots in 60 days. These results indicate active nematode reproduction and substantial hybrid-dependent variation in host response. Experiment 3 examined the impact of varying initial inoculum densities (500, 1000 and 1500 PNC kg(-)(1) soil), showing a dose-dependent increase in Pf and corresponding root damage. Susceptible hybrid (P9127) exhibited up to 42% root dry weight and 22% shoot dry weight reductions. This study is the first systematic evaluation of PNC resistance in New Zealand maize hybrids. It identifies P9127 and P8805 as highly susceptible, and P0891, P8500, and P1613 as moderately resistant. These findings offer valuable benchmarks for future breeding and support nematode management in New Zealand.

The common pine sawfly, Diprion pini (Linnaeus, 1758) (Hymenoptera: Diprionidae), is a well-known defoliating pest of various pine forests almost all over the world, including Europe. It can cause damage to many pine species but usually opts for Pinus sylvestris Linnaeus and P. nigra subsp. laricio (Poiret) Maire. The prohibition of the use of chemical insecticides in forests (at least for T & uuml;rkiye) has led to the fact that other control methods have come to the fore in the control of this pest. In this respect, biological control agents, which are eco-friendly and can persist in the field over time, providing long-term control for plant protection, have an important potential in the control of D. pini. Therefore, in this study, entomopathogenic fungi were isolated from pine forest soils and identified by gene sequencing and phylogenetic analysis. Ten isolates (DP-37, DP-38, DP-45, DP-46, DP-49, DP-53, DP-54, DP-57, DP-58 and DP-63) were identified as Beauveria pseudobassiana, four isolates (DP-35, DP-41, DP-52, and DP-61) were identified as B. bassiana, and only one isolate was identified as Metarhizium robertsii (DP-15). All isolates were tested against the larvae of the pest under laboratory conditions, and the highest mortality and mycosis values (96.6% and 63.3%, respectively) were obtained from B. pseudobassiana DP-57. This isolate was also tested against the pest under outdoor conditions using different conidial concentrations. Based on probit analysis, the LC50 and LC90 values were estimated to be 1.309 x 107 and 1.21 x 1010 conidia/ml, respectively. The results showed that B. pseudobassiana DP-57 could be a good candidate in the biological control of D. pini.

Spent mushroom substrate (SMS), a waste product from mushroom cultivation, in addition to being rich in essential nutrients for crop growth, contains actively growing mushroom mycelia and metabolites that suppress some plant pathogens and pests. SMS thus has potential for fostering the suppressiveness of soil-borne pathogens of farms. This study determined the potential of using the spent Pleurotus ostreatus substrate (SPoS) to suppress the plant-parasitic nematode Radopholus similis in bananas. R. similis is the most economically important nematode in bananas worldwide. The effect of SPoS on R. similis was assessed through two in vivo (potted plants) experiments between May 2023 and June 2024. Five-month-old East African highland banana (genome AAA) plantlets that are highly susceptible to R. similis were used. In the first experiment, the plantlets were established in 3 L pots containing (i) pre-sterilized soil, (ii) pre-sterilized soil inoculated with nematodes, (iii) pre-sterilized soil mixed with 30% (v/v) SPoS, (iv) pre-sterilized soil mixed with 30% (v/v) SPoS followed by nematode inoculation, (v) SPoS without soil, and (vi) SPoS without soil inoculated with nematodes. The SPoS was already decomposed; thus, it may or may not have contained active mycelia. The nematodes were introduced two weeks after the SPoS application. In the second experiment, SPoS was introduced two weeks after nematode inoculation. The SPoS treatments without soil were not evaluated in the second experiment. Both experiments were monitored over a three-month period. Each screenhouse treatment contained four plants and was replicated thrice. In the first experiment, data were collected on changes in soil nutrient content, below- and aboveground biomass, root deaths, root necrosis due to nematode damage, and R. similis population in root tissues and soil. In the second experiment, data were collected on root deaths and the number of nematodes in root tissues and the soil. The SPoS improved crop biomass yield, reduced root damage, and colonization by R. similis. The potential of SPoS to improve the management of R. similis and banana production under field conditions needs to be determined.