Root Samples Research Articles

Occurrence of Rhizoctonia solani AG-5 Causing Root Rot on Astragalus mongholicus in Northwestern China.

Astragalus mongholicus is a perennial Chinese medicinal herb in the family Leguminosae widely cultivated in China. In September 2023, A. mongholicus plants in a field in Weiyuan County, Gansu Province, showed symptoms of circular or irregular brown, sunken and necrotic lesions, multiple lesions coalesced, and brown longitudinal cracks in the roots. An investigation was performed in a 1998 m2 field with a root rot incidence of 10%, and the severity ranged from 5 to 60% of root surface area. Five rotted root samples were collected. Fragments of symptomatic roots were surface sterilized with 75% ethanol for 10 s, 2% sodium hypochlorite for 2 min, washed three times with sterilized distilled water, and then blotted dry on sterile filter paper. Fragments were placed on potato dextrose agar (PDA) medium and incubated at 25 ± 1°C in darkness for 5 days and five isolates were purified by transferring single hyphal tips to new PDA plates. Isolates WY23AM01 and WY23AM05, two of five isolates with similar morphology, were randomly selected for morphological and molecular identification and pathogenicity tests. Colonies of the fungus were white initially, then turned light brown to brown, raised, and with entire or undulate edges. Sclerotia were brown and produced on PDA after 20 days of incubation at 25 ± 1°C in the dark. Genomic DNA from each of the two isolates was extracted, and the internal transcribed spacer (ITS) region was amplified and sequenced with the primer pair ITS5/ITS4 (White et al. 1990). The sequences of isolates WY23AM01 and WY23AM05 were deposited in GenBank (PQ362092 and PQ362093). Phylogenetic analyses were performed by the maximum likelihood method with ITS sequences for anastomosis groups (AG) of Rhizoctonia solani using MEGA 10.0. The phylogenetic tree grouped the two isolates within the R. solani AG-5 clade with high bootstrap support (99%). PCR analysis was performed with 21 primers specifically designed to detect individual anastomosis groups or anastomosis subgroups of R. solani (Carling et al., 2002; Misawa and Kurose, 2019; Misawa et al., 2020; Okubara et al., 2008). Among the 21 specific primer pairs, only AG-5 specific primer amplified the fungal DNA, indicating that the two isolates belonged to the R. solani AG-5. For pathogenicity tests, two isolates were grown individually on sterile wheat kernels at 25 ± 1°C for 10 days. Certified pathogen-free seedling stage roots were grown in the plastic pot filled with the commercially available sterilized horticultural soil and inoculated by burying twenty infested wheat kernels in the soil adjacent to the roots. Control plants were inoculated with sterile wheat kernels using the same procedure. Each pot had three roots, and each treatment had 12 pots as replicates. All plants were placed in a greenhouse with 60% relative humidity and a 12h/12h light/dark photoperiod at 15 to 30°C. Sixty days after inoculation, typical root rot symptoms developed on all inoculated plants, similar to symptoms observed in the field, whereas control plants remained symptomless. The pathogenicity test was performed three times and symptoms were similar to those observed in the field. Finally, fungal isolates were reisolated from the symptomatic roots of all inoculated plants and identified as R. solani AG-5 by molecular analysis as the isolates used for inoculation, thus fulfilling Koch's postulates. To our knowledge, this is the first confirmed report of R. solani AG-5 causing root rot on A. mongholicus in China. Our findings improve knowledge about R. solani AGs occurring in A. mongholicus fields in China and broadens the host range of R. solani AG-5. Due to serious damages caused by this disease in recent years in China, further studies should be conducted to investigate the diversity, prevalence, disease control measures and fungicide sensitivity of AGs distributed in the main A. mongholicus-producing areas in China.

The influence of tooth shade on near-infrared light transmission through human dentine and enamel: an in-vitro study

This in-vitro study assessed the influence of the shade of human teeth on the transmission of near-infrared light. A total of 40 teeth were used. After cleaning the root surface and removing cementum, the teeth were sectioned into slices 3 mm thick, with each comprising a portion of the crown (enamel-dentine (ED)) and of the root (dentine only). The shade of the crown and the root was measured using a digital spectrophotometer. All samples were irradiated using 660, 808, or 904 nm diode lasers, and a multi-wavelength LED light source (700–1100 nm, Nuralyte®). Using a laser power meter, the percent transmission was calculated. Differences between Vita shade groups A, B, and C were analysed using ANOVA and post-hoc tests. Overall, dentine samples showed approximately 40% greater transmission than samples of enamel and dentine. There were significant influences for shade group and for sample thickness on the transmission of 660 nm light (P < 0.01), but not for other light sources. There was a statistically significant influence of light source on transmission. Across both crown and root samples, the ranking for light transmission from greatest to least was LED (700–1100 nm) > (904 nm = 808 nm) > 660 nm. Within the range from 660 to 1100 nm, the longer wavelengths are transmitted better by both enamel and dentine. The transmission of visible red light (660 nm) was affected by Vita tooth shade, while the transmission of near infrared light (700–1100 nm) was not affected by Vita shade.

The interplay between scion genotype, root microbiome, and Neonectria ditissima apple canker.

Severity of European apple canker caused by Neonectria ditissima can vary between locations and apple genotypes. We investigated how location, cold storage/planting season, and apple scion genotype affect root-associated microbial communities. Additionally, we investigated whether differences in abundance of specific taxa could be associated with canker lesion counts. Seven scion cultivars grafted onto M9 rootstocks were inoculated with N. ditissima in the nursery and then planted in December 2018 or stored at 2°C until planting in April 2019 at three sites in Kent, UK. We assessed canker lesions and collected root samples in June 2021. Quantitative PCR and 16S/ITS amplicon sequencing was used to analyse microbial communities. Site was the primary factor affecting microbiome size, diversity, and composition. Cold storage/planting season had small but significant effects, indicating that differences in the microbiome at planting can persist long-term. Scion genotype had a limited effect on diversity but did influence the abundance of specific root associated taxa. Bacterial α-diversity was associated with canker count in a site-dependent manner. Increased abundances of particular fungal (Rhizophagus irregularis and Epicoccum nigrum) and bacterial (Amycolatopsis and Bradyrhizobium) root associated taxa were associated with fewer cankers.

Physicochemical, Pharmacognostical, Phytochemical, Heavy Metal and Pesticidal Residue Analysis of Angelica glauca Edgew roots: An Approach to Establish Quality Standards Using Advanced Analytical Techniques

Background: Angelica glauca (AG) (family Apiaceae) is used by tribes as a spice and to treat various diseases. Before consumption, effective measures must be used for quality control tests. This study establishes quality standards for A. glauca. The study analyses A. glauca roots for physico-chemical, pharmacognostic, phytochemical, heavy metals, pesticidal residue, microbial load, and aflatoxin Methods: The standard procedure was used for powder microscopy and physiochemical parameters. Multiple culture media were used to measure microbial load. Aflatoxins were estimated using HPLC. Mercury, arsenic, lead, cadmium, chromium, and nickel were estimated using graphite furnace atomic absorption spectrometry. To identify 87 pesticide residues in A. glauca roots, LC-MS was used Results: On root powder microscopy, parenchymatous cells packed with yellow material, capillaries with reticulate thickenings, and simple oval to circular starch grains were found. Foreign matter, LOD, total ash, and extractive values were all within range. Salmonela, Pseudomnas, and Coliform (E. coli) were absent. The total viable aerobic bacterial count was 1.14 x 103 cfu/ml, compared to 1.0 x 105 permitted. Aflatoxins were absent in all samples. Heavy metal levels met the FSSR 2011 maximum residue standard for foods not specified. All 87 pesticides in the crude sample were below detection limits, indicating the safety and quality of the A. glauca root sample. Conclusion: The current findings can be utilized in quality control procedures and to assess the quality of A. glauca samples before incorporating them into formulations. Phytochemical tests, heavy metal analysis, and pesticide residue contents can be used to assess quality before using A. glauca raw materials.

Unraveling the shifts in the belowground microbiota and metabolome of Pinus pinaster trees affected by forest decline.

Pinus pinaster Aiton (maritime pine) stands are suffering a generalized deterioration due to different decline episodes throughout all its distribution area. It is well known that external disturbances can alter the plant associated microbiota and metabolome, which ultimately can entail the disruption of the normal growth of the hosts. Notwithstanding, very little is known about the shifts in the microbiota and the metabolome in pine trees affected by decline. The aim of our work was to unravel whether bacterial and fungal communities inhabiting the rhizosphere and root endosphere of P. pinaster trees with symptoms of decline and affected by Matsucoccus feytaudi in the National Park of Sierra Nevada (Granada, Spain) showed alterations in the structure, taxonomical profiles and associative patterns. We also aimed at deciphering potential changes in the rhizosphere and root metabolome. Trees infected by M. feytaudi and healthy individual harbored distinct microbial communities at both compositional and associative patterns. Unhealthy trees were enriched selectively in certain plant growth promoting microorganisms such as several ectomycorrhizal fungi (Clavulina) and Streptomyces, while other beneficial microorganisms (Micromonospora) were more abundant in unaffected pines. The rhizosphere of unhealthy trees was richer in secondary metabolites involved in plant defense than healthy pines, while the opposite trend was detected in root samples. The abundance of certain microorganisms was significantly correlated with several antimicrobial metabolites, thus, being all of them worthy of further isolation and study of their role in forest decline.

Root Development of Tomato Plants Infected by the Cacao Pathogen Moniliophthora perniciosa Is Affected by Limited Sugar Availability.

Moniliophthora perniciosa is the causal agent of the witches' broom disease of cacao (Theobroma cacao), and it can infect the tomato (Solanum lycopersicum) 'Micro-Tom' (MT) cultivar. Typical symptoms of infection are stem swelling and axillary shoot outgrowth, whereas reduction in root biomass is another side effect. Using infected MT, we investigated whether impaired root growth derives from hormonal imbalance or sink competition. Intense stem swelling coincided with a reduction in root biomass, predominantly affecting lateral roots. RNA-seq analyses of root samples identified only a few differentially expressed genes involved in hormone metabolism, and root hormone levels were not expressively altered. Inoculation of the auxin highly-sensitive entire mutant genotype maintained the impaired root phenotype; in contrast, the low-cytokinin MT transgenic line overexpressing CYTOKININ OXIDASE-2 (35S::AtCKX2) with fewer symptoms did not exhibit root growth impairment. Genes involved in cell wall, carbohydrate, and amino acid metabolism were downregulated, accompanied by lower levels of carbohydrate and amino acid in roots, suggesting a reduction in metabolite availability. 13CO2 was supplied to MT plants, and less 13C was detected in the roots of infected MT but not in those of 35S::AtCKX2 line plants, suggesting that cytokinin-mediated sugar sink establishment at the infection site may contribute to impaired root growth. Exogenous sucrose application to roots of infected MT plants partially restored root growth. We propose that the impairment of lateral root development is likely attributed to disrupted sugar signalling and photoassimilate supply by establishing a strong sugar sink at the infected stem.

Seasonal dynamics of kiwifruit microbiome: A case study in a KVDS-affected orchard.

Over the past decade, Italian kiwifruit orchards and overall production have faced a significant threat from Kiwifruit Vine Decline Syndrome (KVDS). Despite the insights gained from metagenomics studies into the microbial communities associated with the disease, unanswered questions still remain. In this study, the evolution of bacterial, fungal, and oomycetes communities in soil and root endosphere at three different time points during the vegetative season was investigated for the first time in a KVDS-affected orchard in the Lazio Region. The fungal and oomycetes genera previously associated with the syndrome, including Fusarium, Ilyonectria, Thelonectria, Phytophthora, Pythium and Globisporangium, were identified in both groups. In contrast, the characterization of bacterial communities revealed the first instance of the presence of the genus Ralstonia in soil and root samples. The microbiome composition shifts between KVDS-affected and asymptomatic plants were significant as evidenced by the results, particularly after a temperature increase. This temperature change coincided with the onset of severe disease symptoms and may indicate a key role in the progression of KVDS.

Indigenous arbuscular mycorrhizal fungi at tangerine cv. Tejakula (Citrus reticulata cv. Tejakula) plantations, their colonization of the roots, and their effect on soil fertility

Tangerines (Citrus reticulata var. Tejakula) were destroyed in 1984 by CVPD, allegedly because the use of chemicals was too intensive, resulting in land degradation. Since ten years ago, these oranges have been successfully cultivated again using healthy organic cultivation, but farmers have difficulty getting organic fertilizer. This research aimed to identify and isolate the Arbuscular Mycorrhizal Fungi (AMF) on tangerines cv. Tejakula, their colonization of the roots and effect on soil fertility. Exploration was conducted by collecting root and soil samples in tangerine cv. Tejakula production centers are in the Tejakula District, Buleleng Regency. Spore isolation was conducted using wet filtration and centrifugation techniques, while root colonization by AMF was carried out using the staining method with trypan blue. The isolated spores are composited into AMF biofertilizer using volcanic sand as a carrier medium. The biofertilizer was then tested for its effect on soil fertility with three treatment levels of AMF spore doses (0, 20, and 40 spores/50 g of carrier media per plant). The results of exploration, isolation, and identification showed that three genera and six species of AMF were found. The spore density ranged from 17 to 32 per 100 g of soil (mean 24.17 ± 2.02 spores). The average root colonization by AMF was very high, ranging from 90 to 100%, and the application of AMF biofertilizer at a dose of 20 and 40 spores per plant provided soil fertility was much better than the control (0 AMF spores per plant).

Improved methodology for tracing a pulse of 13C-labelled tree photosynthate carbon to ectomycorrhizal roots, other soil biota and soil processes in the field.

Isotopic pulse-labelling of photosynthate allows tracing of carbon (C) from tree canopies to belowground biota and calculations of its turnover in roots and recipient soil microorganisms. A high concentration of label is desirable, but is difficult to achieve in field studies of intact ecosystem patches with trees. Moreover, root systems of trees overlap considerably in most forests, which requires a large labelled area to minimize the impact of C allocated belowground by un-labelled trees. We describe a method, which combines a high level of labelling at ambient concentrations of CO2, [CO2], with undisturbed root systems and a model to account for root C and root-derived C from un-labelled trees. We raised 5-m-tall chambers each covering 50 m2 of ground (volume 250 m3) in a young boreal Pinus sylvestris L. forest with up to 5m tall trees. Rather than a conventional single release of 13CO2, we used five consecutive releases, each followed by a draw-down period, thus avoiding high [CO2]. Hence, we elevated successively the 13CO2 from 1.1 to 23 atom% after the first release to 61 atom% after the fifth, while maintaining [CO2] below 500ppm during 4 to 4.5h of labelling. The average abundance of 13CO2 was as high as 42 atom%. We used the central 10 m2 of the 50 m2 area for sampling of roots and other soil biota. We modeled the dilution of labelled C across the plots by un-labelled C from roots of trees outside the area. In the central 10 m2 area, around 85% of roots and root-associated biota received C from labelled trees. In summary, we elevated the labelling of roots and associated soil biota four-fold compared to in previous studies, and described the commonly overlooked impact of roots from un-labelled trees outside the labelled area.

Unveiling root nodulation in Tribulus terrestris and Roystonea regia via metagenomics analysis.

Root nodule symbiosis is traditionally recognized in the Fabales, Fagales, Cucurbitales, and Rosales orders within the Rosid I clade of angiosperms. However, ambiguous root nodule formation has been reported in Zygophyllaceae and Roystonea regia (Arecaceae), although a detailed analysis has yet to be conducted. We aimed to perform morphological analyses of root structures in these plants and utilize metagenomic techniques to identify and characterize the bacterial populations within the nodule-like structures. We collected root samples of Tribulus terrestris (Zygophyllaceae) and Roystonea regia from West Asia and the Caribbean, respectively. We conducted detailed morphological analyses of nodule-like structures, isolated and genome-sequenced the endophytes, and employed metagenomic techniques to identify the bacterial populations within these formations. We observed nodule-like structures in both plant species. Symbiosomes, which are hallmark structures of nodulating plants, were not detected. Metagenome sequence data analysis revealed potential nodulating and nitrogen-fixing bacteria in the nodule-like structures of both species. Canonical nodulation and nitrogen-fixation genes were identified in microbes associated with the nodules. However, the phylogenomic analysis showed that the bacteria isolated from T. terrestris and R. regia are within Gammaproteobacteria and Bacilli, which are not typically known as nodulating bacteria. The observed structures differ significantly from traditional nodules found in legumes and actinorhizal plants, suggesting unique characteristics with hosting nitrogen-fixing bacteria. Although bacteria identified through in silico analysis or culture are well-known nitrogen-fixers, their specific role in root nodule formation remains to be investigated.

CHARACTERISTICS OF RADIONUCLIDE ACCUMULATION IN DANDELION ROOTS IN THE CENTRAL BLACK EARTH REGION

The aim of the study is to examine accumulation patterns of natural and man-made radioactive isotopes in dandelion roots (Taraxacum officinale F.H. Wigg.), harvested in different areas of the Voronezh region. Materials and Methods. Under experiment, the specific activity of the main long-lived artificial radioisotopes (cesium-137, strontium-90) and naturally occurring radionuclides (thorium-232, potassium-40, radium-226) was determined in the samples of top soil and dandelion roots using a MKGB-01 RADEK spectrometer-radiometer. Results. All the studied samples of dandelion roots conform to the existing radiation safety requirements (first group). With the increase in the specific activity of strontium-90, cesium-137, thorium-232, potassium-40, and radium-226 in the soil, their specific activity in plant roots also increased. Correlation analysis of the specific activity of man-made and natural radionuclides in the soil and roots demonstrated a very noticeable correlation, which confirmed the predominant trans-soil root contamination. The calculated accumulation factors of radionuclides in dandelion roots showed fast accumulation of strontium-90 and radium-226 from soils. The specific activity of these radioisotopes in medicinal plant raw materials was significantly higher than that in soil. A detailed analysis of the dependence of the calculated accumulation coefficients of natural and man-made radioisotopes in dandelion roots allowed us to note the tendencies towards their decrease with an increase in the specific activity of the radionuclide in soil. This fact indicates the existence of physiological mechanisms regulating their accumulation in plant roots. The transition patterns of the studied natural and man-made radionuclides are described by mathematical dependencies with the maximum coefficient of approximation reliability.

GDSMOTE: A Novel Synthetic Oversampling Method for High-Dimensional Imbalanced Financial Data

Synthetic oversampling methods for dealing with imbalanced classification problems have been widely studied. However, the current synthetic oversampling methods still cannot perform well when facing high-dimensional imbalanced financial data. The failure of distance measurement in high-dimensional space, error accumulation caused by noise samples, and the reduction of recognition accuracy of majority samples caused by the distribution of synthetic samples are the main reasons that limit the performance of current methods. Taking these factors into consideration, a novel synthetic oversampling method is proposed, namely the gradient distribution-based synthetic minority oversampling technique (GDSMOTE). Firstly, the concept of gradient contribution was used to assign the minority-class samples to different gradient intervals instead of relying on the spatial distance. Secondly, the root sample selection strategy of GDSMOTE avoids the error accumulation caused by noise samples and a new concept of nearest neighbor was proposed to determine the auxiliary samples. Finally, a safety gradient distribution approximation strategy based on cosine similarity was designed to determine the number of samples to be synthesized in each safety gradient interval. Experiments on high-dimensional imbalanced financial datasets show that GDSMOTE can achieve a higher F1-Score and MCC metrics than baseline methods while achieving a higher recall score. This means that our method has the characteristics of improving the recognition accuracy of minority-class samples without sacrificing the recognition accuracy of majority-class samples and has good adaptability to data decision-making tasks in the financial field.

Native beauveria bassiana isolates: harnessing endophytic capabilities for controlling fall armyworm infestation in maize

ABSTRACT This study investigates the establishment and colonization dynamics of Beauveria bassiana as an endophyte in maize plants using various inoculation methods. Surface sterilization and fungal isolation confirmed B. bassiana as an endophyte, with isolates ChBb and NaBb exhibiting distinct colonization patterns. Notably, foliar spray demonstrated the highest initial colonization efficiency, with ChBb achieving 93.3% in leaves at 7 days post-inoculation (DPI), decreasing to 13.3% at 35 DPI. NaBb similarly exhibited high initial colonization via foliar spray, with 93.3% in leaves at 7 DPI, declining to 33.3% at 35 DPI. Molecular analysis using nested PCR confirmed the presence of B. bassiana DNA exclusively in treated tissues, with a consistent 300 bp PCR product observed in leaf, stem, and root samples. Phylogenetic analysis highlighted genetic relationships among B. bassiana isolates, underscoring their diversity and potential for biocontrol applications. Pathogenicity tests against Spodoptera frugiperda demonstrated significant mortality rates: ChBb achieved 77.20% mortality in direct contact assays (where larvae were exposed directly to the fungal spores) and 56.82% mortality in vivo (where larvae were fed plants colonized by the fungus), while NaBb resulted in 75.86% and 51.42% mortality, respectively. These findings emphasize the efficacy of B. bassiana as a biocontrol agent, particularly through foliar application for initial colonization in maize plants.

Effects of cadmium toxicity on growth and biochemical properties of chickpea (Cicer arietinum L.)

Growing concerns about climate change require more knowledge regarding plant-environment interaction and more importantly how our economically important crops are adopting diverse heavy metal pollutants to confer food security. The effect of cadmium (Cd) on the growth and biochemical features of chickpea (Cicer arietinum L.) plants grown in sand culture was evaluated to better understand heavy metal toxicity and crop adaptability during the present study. Four different concentrations of Cd namely 250 µM, 500 µM, 750 µM and 1000 µM along with control were considered at 7 days, 14 days, and 21 days of treatment on selected Chickpea var. BARI Chola 5. Growth was determined by measuring fresh weight and height. Several biochemical tests (e.g. protein, proline, antioxidant enzymes, and lipid peroxidation) were conducted using root samples mainly in addition to leaves for chlorophyll and sugar measurements. Due to Cd application, chickpea plants exhibited stunted growth with chlorosis, and plant height and weight were reduced compared to control-treated plants. Also, Cd toxicity resulted in a reduction in chlorophyll a, chlorophyll b, and total chlorophyll in the leaves of chickpeas. Though exposure of Cd at 7 days of treatment showed variable response in reducing and total sugar content; both the 14 and 21 days of treatment exerted a depletion. Cd stress increased proline content from 7 to 21 days of treatment in the chickpea roots. However, total protein content was found to be declined in Cd-treated chickpea roots compared to control. Cd treatment caused an increase in peroxidase and catalase activity whereas membrane damage rate decreased with increasing concentration of Cd. The present study demonstrated how crop plants like chickpeas are physically and biochemically adapted to various concentrations of Cd stress with a time-series experiment and their potential to tolerate Cd at different stages of their growth.

Концентрация на микроелементи в генотипи градински грах под влияние на инокулация с арбускуларни микоризни гъби и полезни ризобактерии

The influence of a microbial inoculant Europlus®, containing AM fungi (Glomus sp.) and beneficial rhizobacteria (Bacillus sp.), on the concentration of micronutrients (Fe, Mn, Zn and Cu) in the aboveground biomass and roots of six garden pea genotypes was studied. The experiment was conducted under field conditions in the Maritsa Vegetable Crop Research Institute on Alluvial-meadow soil. It was found that the microbial inoculant had a weak effect on the agrochemical properties of the soil. The combined inoculation increased the concentration of Fe in the aboveground biomass of most genotypes by 2.4%-22.9%. The increase of iron in the roots was by 4.4%-12.6%. Application of combined inoculant, in some cases, increased the Mn concentration in the aboveground biomass of genotypes - by 9.3%-35.7% compared to the controls. This was associated with an increased in Zn concentrations (+2.1%-64.9%) and Cu concentrations (+5.2%-20.2%) in aboveground biomass of inoculated genotypes. Microbial inoculant application increased root Mn, Zn and Cu concentrations by 4.8%-35.1%, 5.3%-20.8% and 3.3%-24.4%, respectively, compared to non-inoculated controls. The response of the individual pea genotypes to the formation of symbiosis with AM fungi was different. The bioinoculant increased root colonization rates with AM fungi by over 7% on average. A correlation was recorded only with Fe concentrations. The genotype factor had a greater effect on the micronutrient concentrations in pea samples. Inoculation with AM fungi and beneficial rhizobacteria had a weaker effect, but it was also statistically significant in terms of the concentration of Fe, Mn and Zn in aboveground biomass and roots. Hierarchical cluster analysis classified the aboveground samples of pea genotypes from the inoculated and non-inoculated treatments into two main clusters based on the concentration of micronutrients. The 12 root samples were divided into 3 groups.

Quantification of growth and physiological characteristics in tolerant and sensitive watermelon lines under cold treatment

AbstractBiochemical and physiological processes serve as key indicators for assessing the adverse effects of biotic and abiotic stressors in plants. Due to the limited and incomplete information on the growth, root morphology, and physiology of watermelon lines under cold stress in Korea, this study aimed to evaluate selected cold-tolerant lines (PI254744, SW20, and SW66) and cold-sensitive lines (PI525233 and SW54). The evaluation was based on root and shoot weight, root and shoot length, root morphology, photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids), and levels of proline, malondialdehyde (MDA), and soluble sugars in root and leaf samples collected at various time points. Two treatments were conducted: one at 28 °C as a control and one at 10 °C to simulate cold stress. The results revealed a decline in growth variables under cold stress compared to the control across all lines. However, the disintegration of root cellular structures and reduction in growth variables were less severe in the tolerant watermelon lines than in the sensitive ones. Under cold stress, proline, MDA, and soluble sugar levels increased in all watermelon lines relative to the control. Notably, the tolerant lines displayed elevated proline and soluble sugar levels, while the sensitive lines had higher MDA content. Furthermore, photosynthetic pigment levels were generally lower in all lines during cold treatment compared to the control, though the reduction was less pronounced in the tolerant lines than in the sensitive ones. A significant positive correlation was found between the percentage reduction in total chlorophyll content and the percentage reduction in growth variables. The lesser reduction in photosynthetic pigments, combined with higher levels of osmoprotectants (proline and soluble sugars) and lower MDA levels in the tolerant lines during cold stress, may suggest underlying mechanisms that warrant further biochemical and molecular studies to better understand cold resistance.

A method evaluating ectomycorrhizal fungal colonization in vitro by using relative quantitative PCR

ABSTRACT Ectomycorrhiza (ECM) significantly influences the establishment and stability of forest ecosystems. While evaluating ECM colonization is important for ECM symbiosis research, conventional methods using microscopes prove both time-intensive and subjective. To overcome this, we developed a high throughput and objective method for evaluating ECM colonization in a target tree under laboratory conditions by using quantitative PCR (qPCR). Primers specific for Populus tomentosa, Cenococcum geophilum (Cg), and Laccaria japonica (Lj) were designed and validated. After separately inoculating Cg and Lj, as well as co-inoculating Cg and Lj to P. tomentosa, the root samples were harvested at three different time points; 10, 20, and 40 days post-inoculation. ECM colonization was assessed by conventional microscopic method and qPCR with the designed primers. The designed primers showed a high specificity and quantitativity for each species, indicating their practical use in quantifying individual ECM species in tripartite conditions. Both ectomycorrhizal species showed a positive correlation between the conventional method and the qPCR method: Cg (Spearman correlation = 0.917, p < 0.001), Lj (Spearman correlation = 0.690, p < 0.01). Therefore, by using highly species-specific primers, we established a method to evaluate ECM colonization in vitro by qPCR, which can be an alternative and solution to the conventional method.

Mycobiome analysis of leaf, root, and soil of symptomatic oil palm trees (Elaeis guineensis Jacq.) affected by leaf spot disease.

Recently, attention has been shifting toward the perspective of the existence of plants and microbes as a functioning ecological unit. However, studies highlighting the impacts of the microbial community on plant health are still limited. In this study, fungal community (mycobiome) of leaf, root, and soil of symptomatic leaf-spot diseased (SS) oil palm were compared against asymptomatic (AS) trees using ITS2 rRNA gene metabarcoding. A total of 3,435,417 high-quality sequences were obtained from 29 samples investigated. Out of the 14 phyla identified, Ascomycota and Basidiomycota were the most dominant accounting for 94.2 and 4.7% of the total counts in AS, and 75 and 21.2% in SS, respectively. Neopestalotiopsis is the most abundant genus for AS representing 8.0% of the identified amplicons compared to 2.0% in SS while Peniophora is the most abundant with 8.6% of the identified amplicons for SS compared to 0.1% in AS. The biomarker discovery algorithm LEfSe revealed different taxa signatures for the sample categories, particularly soil samples from asymptomatic trees, which were the most enriched. Network analysis revealed high modularity across all groups, except in root samples. Additionally, a large proportion of the identified keystone species consisted of rare taxa, suggesting potential role in ecosystem functions. Surprisingly both AS and SS leaf samples shared taxa previously associated with oil palm leaf spot disease. The significant abundance of Trichoderma asperellum in the asymptomatic root samples could be further explored as a potential biocontrol agent against oil palm disease.

Evaluation of Antimicrobial Activity of Aqueous and Acetone Root Extracts from Cordia dichotoma

The emergence of antibiotic resistance has renewed interest in exploring plant-based antimicrobial compounds. This study investigated the antimicrobial potential of root extracts from Cordia dichotoma, a traditional medicinal plant widely distributed across Asia. Root samples were collected and extracted using two solvents (acetone and distilled water) through both maceration and Soxhlet extraction methods. Preliminary phytochemical screening revealed the presence of alkaloids, phenolic compounds, glycosides, tannins, and flavonoids across different extracts. The antimicrobial activity was evaluated against both Gram-positive (Bacillus pumilus) and Gram-negative (Escherichia coli) bacteria using the well diffusion method. The acetone maceration extract demonstrated superior antimicrobial activity with 90% inhibition against both test organisms, showing zones of inhibition of 52.5 mm and 51 mm against B. pumilus and E. coli, respectively. The Soxhlet acetone extract showed moderate activity with 58% inhibition against B. pumilus and 52% against E. coli. Aqueous extracts exhibited comparatively lower antimicrobial activity, with the Soxhlet extract showing 44% inhibition against B. pumilus and 58% against E. coli, while the maceration extract showed 50% and 37% inhibition, respectively. These findings suggest that acetone is a more effective solvent for extracting antimicrobial compounds from C. dichotoma roots, with the maceration process yielding better results than Soxhlet extraction. This study provides scientific validation for the traditional use of C. dichotoma in treating infectious diseases and suggests its potential as a source of novel antimicrobial compounds.

Optimization and Chemical Characterization of Extracts Obtained from Ferula persica var. latisecta Aerial Parts and Roots and Their Neuroprotective Evaluation.

The genus Ferula has been traditionally used for the treatment of various illnesses, but the potential of Ferula persica var. latisecta against different Alzheimer's disease (AD) hallmarks has never been achieved. In this work, a pressurized liquid extraction (PLE) method was optimized to extract F. persica L. aerial parts and roots. Four different solvents (water, ethanol, ethyl acetate (EtAc), and cyclopentyl methyl ether (CPME)) were first tested, and the extraction yield, total phenolic content, reactive oxygen species scavenging capacity, and acetylcholinesterase (AChE) inhibition activity were evaluated. The results indicated that EtAc and CPME were the best solvents to be used, with the results obtained from the aerial parts being better than those obtained from the root samples. Thereafter, the PLE method was further optimized by combining these solvents in different percentages (100% EtAc, 100% CPME, and 50:50% (v/v) EtAc:CPME) and temperatures (50, 115, and 180 °C). Response surface methodology was then applied to analyze the data, and two optimum extraction conditions were obtained: EtAc:CPME (79:21%) at 180 °C for the aerial parts and 100% CPME at 180 °C for the roots. At these conditions, the total flavonoid content (TFC) and the inhibitory capacities against butyrylcholinesterase (BChE) and lipoxygenase (LOX) enzymes were also evaluated, indicating that the aerial part extracts had higher TFC and LOX inhibitory capacity than the root extracts but lower activity against BChE. The comprehensive LC/GC-MS chemical characterization allowed for the tentative identification of 222 compounds belonging to 66 chemical subclasses, the abundancies of which widely varied depending on the matrix and the extraction conditions used. The results obtained together with the application of advanced statistical analysis and molecular docking simulations suggested several sesquiterpenoids, such as selina-3,7(11)-diene, guaiol acetate, α-cyperone, and farnesyl acetate, as the molecules responsible of the in vitro results observed, with good neuroprotective potential against AD.