Tissue Maceration Research Articles

Novel Antarctic Endo-Polygalacturonase for Pectin Extraction and Vegetal Tissue Maceration at Mild Temperatures.

The aim of the present work was to partially purify and characterize an Antarctic polygalacturonase and to determine the enzyme's potential in pectin extraction and vegetal maceration at 20°C. Polygalacturonase was purified by chromatography to obtain an enzymatic preparation of specific activity 30.3 U.mg-1. Optimal conditions for the polygalacturonase activity were 45°C and pH 5.0-6.0, and the activation energy for the reaction was 41.8kJ.mol-1. Of the enzyme activity, 100% was retained after 3h at 40°C. The enzyme was remarkably stable for an hour over a wide range of pH (2.0-12.0). Polygalacturonase activity was slightly reduced in the presence of Ca+2, Fe+3, K+, Mn+2, and Zn+2, whereas Hg+2 reduced the activity by 60%, suggesting a thiol-dependent catalysis. The apparent molecular weight of the enzyme was 33kDa. The kinetic constants evaluated against polygalacturonic acid were 0.17mg.ml-1 (Km), 480s-1 (Kcat), and 7.9µmol.mg-1.min-1 (Vmax). The enzyme was active against different pectic substrates. Thin-layer chromatography revealed an endo-mechanism of action. Polygalacturonase digested lime pomace to aid the extraction of high-methoxylated pectin at 20°C and increased the vegetal maceration of Capsicum annuum by 24% over the control values.

Essential Oils of Some Potential Medicinal Plants and their Wound Healing Activities.

The wound has been recognised as a deep cut or tearing of the epidermis, which is also referred to as trauma and harm to the body tissues. Healing of wounds requires a coordinated series of cellular processes, including cell attraction, proliferation, differentiation, and angiogenesis. These processes involve interactions between various cells, such as macrophages, endothelial cells, keratinocytes, fibroblasts, growth hormones, and proteases. The outcome of wounds can be fatal if not treated properly, resulting in chronic wounds, chronic pain, and even death. Wound healing is replacing missing tissue with tissue repairs and regeneration. Some local variables are the presence of tissue maceration, foreign objects, biofilm, hypoxia, ischemia, and wound infection. Sustained growth factor delivery, siRNA delivery, micro-RNA targeting, and stem cell therapy are all emerging possible therapeutic approaches for wound healing. Traditional approaches, such as Ayurveda, Siddha, and Unani medicines, are also being used for treatment. The therapeutic application of nanoformulations in wound infections has shown various beneficial effects. Several herbal medicines, especially essential oils have shown potential wound healing activities, such as lavender, tea tree, sesame, olive, etc. Various nanoparticles and their nanoformulations have been explored in wound healing therapy. The present review article highlights several aspects of essential oils for wound healing activity through a novel drug delivery system. Further, some patents on wound healing through herbal medicine have been listed.

Ecomorphology of main food processing structures of four ocypodid species: how do they relate to the crabs’ trophic habits?

The spoon-tipped (ST) setae coverage and their abundance on the second maxillipeds as well as the morphology of the urocardiac and zygocardiac ossicles from the gastric mills of the four ocypodid species, viz., Austruca annulipes (H. Milne Edwards, 1837), Gelasimus vocans (Linnaeus), 1758, two typical deposit-feeding fiddler crabs, Petruca panamensis (Stimpson, 1859), an atypical herbivorous-cum-‘sediment swallower’ fiddler crab, and Ocypode ceratophthalmus (Pallas, 1772), an omnivorous ghost crab, were described and compared in relation to their respective trophic habits. In the three fiddler crabs, ST setae coverage and abundance generally correlated with their habitats’ sediment grain size characteristics—more ST setae in A. annulipes (‘sandy-habitat crab’) and less in G. vocans (‘muddy-habitat crab’). ST setae were absent in O. ceratophthalmus, which suggests that these setae were not needed for food processing. In the two deposit-feeding fiddler crabs, the median tooth of the urocardiac ossicle had tooth-like transverse ridges to grind against the dentition of the lateral teeth of the zygocardiac ossicles. The median tooth in P. panamensis, however, had transverse ridges that resemble that of a vascular plant eater as well as some posterior tooth-like transverse ridges, typically found in deposit feeders; and twice the number of incisors than the other three ocypodids, for cutting up ingested algal pieces. The omnivorous O. ceratopthalmus had four raised transverse ridges on the round blunt median tooth as well as large premolars and molars on the zygocardiac lateral teeth for maceration of animal tissue. Hence, ST setae abundance as well as the grinding surfaces and dentition of the two gastric mill ossicles are indicative of the habitat adaptations and trophic habits respectively.

Low cost and biocompatible Marine algae derived scaffolds: enhancing tissue regeneration in oral cancer surgery

Efficient tissue regeneration following oral cancer surgery is crucial for maintaining function. Seaweed-derived scaffold materials, with their resemblance to oral tissue structure, promote cell adhesion and differentiation. Their high porosity aids in exudate absorption, reducing infection risks and tissue maceration. Further scaffold breakdown releases growth factors, aiding tissue regeneration. Easily integrated into dressings or gels, these scaffolds accelerate healing and protect against contaminants. Their biocompatibility and safety ensure minimal adverse effects. Seaweed-derived scaffolds offer a natural, sustainable approach to tissue repair, making them ideal for post-oral surgery dressing, facilitating effective tissue regeneration.

Monilinia fructicola genes involved in the cell wall-degrading process in early nectarine infection

Brown rot symptoms may be linked to alterations in the gene expression pattern of genes associated with cell wall degradation. In this study, we identify key carbohydrate-active enzymes (CAZymes) involved in cell wall degradation by Monilinia fructicola, including pme2 and pme3 (pectin methylesterases), cut1 (cutinase) and nep2 (necrosis-inducing factor). The expression of these genes is significantly modulated by red and blue light during early nectarine infection. The polygalacturonase gene pg1 and the cellulase gene cel1 also exhibit photoinduction albeit to a lesser extent. Red and blue light cause an acceleration in the initial stages of brown rot development caused by M. fructicola on nectarines. Disease symptoms like tissue maceration were evident after an incubation period of 24 h followed by 14 h of light exposition, in contrast to the usual incubation period of 48 to 72 h. Furthermore, the culture media exerts an impact on gene regulation, suggesting a complex interplay between light and nutrient signalling pathways in M. fructicola. In addition, we observe that red light promotes colony growth on a 12 h photoperiod and consistently reduces conidiation. In contrast, blue light hampers growth rate on both the 12 h and the 8 h photoperiod but only diminishes conidiation on the 12 h photoperiod. These findings enhance our comprehension of genes associated with cell wall degradation and the environmental factors influencing brown rot development.

A review of Bone Preparation Techniques for Anatomical Studies

The scope of modern anatomy has become very wide because it is now studied by all possible techniques which can enlarge the boundaries of the anatomical knowledge. So, bones are essential part of anatomy teaching curriculum and are unsurpassed in the ability to provide three dimensional instruction in Osteology as well as understanding the sites of soft tissue insertion and the course of neurovascular structures in a region. Many techniques have been employed over the years for preparation of bones. These methods include the use of insects, chemicals and enzymes. Bone preparation involves soft tissue removal, maceration, bleaching and labelling of the bones. The present study conducted with the aim of evaluating the least time-consuming and effective method of bone preparation from embalmed and wet specimens.

Evaluation of the Venous System of Wistar Rat Liver by Injection with Epoxy Resin

The rat is the most widely used experimental model in surgical research due to several factors, including that it is easy to handle and inexpensive. It can be used in investigations related to liver regeneration, liver metastases, or transplant immunology. This study highlights the venous components of the hepatic circulation in the Wistar rat by intravascular injection of a polymer that allows the assessment of the distribution of vessels, regardless of their caliber. Five cadavers of 11-month-old male Wistar rats from the USAMV Cluj-Napoca biobase destined for incineration, were used to highlight the liver venous system. A dye mixture, consisting of epoxy resin-catalyst-blue acrylic dye in a 2:1:1 ratio, was injected. After 24 hours, biological tissues were macerated by immersion in 10% KOH solution for five days. The intrahepatic venous system is represented by the venous branches that continue into the liver lobes. Those vessels follow a parallel trajectory with the hepatic artery branches represented by the right and left ramifications. The right portal vein presents branches to the lateral and medial parts of the right lobe of the liver and the caudate lobe. The left branch of the portal vein has ramificationsfor the lateral and medial parts of the left lobe and the quadrate lobe. The technique of injecting the venous circulation of the liver, followed by tissue maceration, allowed the removal by anatomical dissection of all liver components that permits the identification of all components of the venous system, including the finest venous branches of the hepatic circulation.

A maceration technique for soft plant tissue without hazardous chemicals.

Current methods for maceration of plant tissue use hazardous chemicals. The new method described here improves the safety of dissection and maceration of soft plant tissues for microscopic imaging by using the harmless enzyme pectinase. Leaf material from a variety of land plants was obtained from living plants and dried herbarium specimens. Concentrations of aqueous pectinase and soaking schedules were optimized, and tissues were manually dissected while submerged in fresh solution following a soaking period. Most leaves required 2-4 h of soaking; however, delicate leaves could be macerated after 30 min while tougher leaves required 12 h to 3 days of soaking. Staining techniques can also be used with this method, and permanent or semi-permanent slides can be prepared. The epidermis, vascular tissue, and individual cells were imaged at magnifications of 10× to 400×. Only basic safety precautions were needed. This pectinase method is a cost-effective and safe way to obtain images of epidermal peels, separated tissues, or isolated cells from a wide range of plant taxa.

Emergence of the Dickeya genus involved duplication of the OmpF porin and the adaptation of the EnvZ-OmpR signaling network.

Genome evolution, and more specifically gene duplication, is a key process shaping host-microorganism interaction. The conserved paralogs usually provide an advantage to the bacterium to thrive. If not, these genes become pseudogenes and disappear. Here, we show that during the emergence of the genus Dickeya, the gene encoding the porin OmpF was duplicated. Our results show that the ompF2 expression is deleterious to the virulence of Dickeya dadantii, the agent causing soft rot disease. Interestingly, ompF2 is regulated while ompF is constitutive but activated by the EnvZ-OmpR two-component system. In vitro, acidic pH triggers the system. The pH measured in four eudicotyledons increased from an initial pH of 5.5 to 7 within 8 h post-infection. Then, the pH decreased to 5.5 at 10 h post-infection and until full maceration of the plant tissue. Yet, the production of phenolic acids by the plant's defenses prevents the activation of the EnvZ-OmpR system to avoid the ompF2 expression even though environmental conditions should trigger this system. We highlight that gene duplication in a pathogen is not automatically an advantage for the infectious process and that, there was a need for our model organism to adapt its genetic regulatory networks to conserve these duplicated genes. IMPORTANCE Dickeya species cause various diseases in a wide range of crops and ornamental plants. Understanding the molecular program that allows the bacterium to colonize the plant is key to developing new pest control methods. Unlike other enterobacterial pathogens, Dickeya dadantii, the causal agent of soft rot disease, does not require the EnvZ-OmpR system for virulence. Here, we showed that during the emergence of the genus Dickeya, the gene encoding the porin OmpF was duplicated and that the expression of ompF2 was deleterious for virulence. We revealed that while the EnvZ-OmpR system was activated in vitro by acidic pH and even though the pH was acidic when the plant is colonized, this system was repressed by phenolic acid (generated by the plant's defenses). These results provide a unique- biologically relevant-perspective on the consequence of gene duplication and the adaptive nature of regulatory networks to retain the duplicated gene.

Application of Biosynthesized Silver Nanoparticles from Oak Fruit Exudates against Pectobacterium carotovorum subsp. carotovorum Causing Postharvest Soft Rot Disease in Vegetables

The main goal of our study was to determine whether biosynthesized silver nanoparticles (SNPs) could be used as a novel antibacterial material in order to control soft rot in vegetables. Exudates from oak fruit were used in the green synthesis of SNPs. Postharvest soft rot disease in vegetables has resulted in significant crop losses all over the globe. Because managing Pectobacterium carotovorum subsp. carotovorum (Pcc), the causal agent of soft rot disease, is difficult due to its wide host range, developing innovative disease-management methods that do not involve the use of hazardous chemicals is a top priority for maintaining sustainable agriculture. The current research has found that silver nanoparticles (SNPs) have a detrimental effect on the progression of Pcc and soft rot disease in in vitro conditions. At SNPs’ sub-MIC, the greatest levels of inhibition against tissue maceration were 22, 19.8, 21.5, and 18.5 percent in potato, zucchini, carrot, and eggplant, respectively. SNP treatment of tubers and fruits had a noteworthy suppressive impact on soft rot disease symptoms as compared to controls. SNPs may be able to replace chemical pesticides in the management and prevention of soft rot disease in vegetables in postharvest settings, according to this study.

Antifungal Activity and Effect of Plant-Associated Bacteria on Phenolic Synthesis of Quercus robur L.

Europe's forests, particularly in Ukraine, are highly vulnerable to climate change. The maintenance and improvement of forest health are high-priority issues, and various stakeholders have shown an interest in understanding and utilizing ecological interactions between trees and their associated microorganisms. Endophyte microbes can influence the health of trees either by directly interacting with the damaging agents or modulating host responses to infection. In the framework of this work, ten morphotypes of endophytic bacteria from the tissues of unripe acorns of Quercus robur L. were isolated. Based on the results of the sequenced 16S rRNA genes, four species of endophytic bacteria were identified: Bacillus amyloliquefaciens, Bacillus subtilis, Delftia acidovorans, and Lelliottia amnigena. Determining the activity of pectolytic enzymes showed that the isolates B. subtilis and B. amyloliquefaciens could not cause maceration of plant tissues. Screening for these isolates revealed their fungistatic effect against phytopathogenic micromycetes, namely Fusarium tricinctum, Botrytis cinerea, and Sclerotinia sclerotiorum. Inoculation of B. subtilis, B. amyloliquefaciens, and their complex in oak leaves, in contrast to phytopathogenic bacteria, contributed to the complete restoration of the epidermis at the sites of damage. The phytopathogenic bacteria Pectobacterium and Pseudomonas caused a 2.0 and 2.2 times increase in polyphenol concentration in the plants, respectively, while the ratio of antioxidant activity to total phenolic content decreased. Inoculation of Bacillus amyloliquefaciens and Bacillus subtilis isolates into oak leaf tissue were accompanied by a decrease in the total pool of phenolic compounds. The ratio of antioxidant activity to total phenolic content increased. This indicates a qualitative improvement in the overall balance of the oak leaf antioxidant system induced by potential PGPB. Thus, endophytic bacteria of the genus Bacillus isolated from the internal tissues of unripe oak acorns have the ability of growth biocontrol and spread of phytopathogens, indicating their promise for use as biopesticides.

Peculiarities of stems flattening at two-phase fiber flax harvesting technology

BACKGROUND: Based on the analysis of the morphological features of fiber flax, authors focus on the technical part of the stem, which contains fiber. To improve the quality and for most complete isolation of this product, the process of tissue maceration should be stimulated by stem flattening.
 AIMS: Search of methods and means of obtaining the maximum effect from the use of two-phase flax harvesting technology, by ensuring uniform flattening along the entire technical length of the stems, starting from the earliest stages of harvesting.
 METHODS: It is noted that the greatest effect of flattening can be achieved with two-phase flax harvesting. However, all known methods and devices involve a time gap between the flattening of different parts of a plant, which leads to a delay in the onset of maceration in untreated parts of a stem, delaying harvesting and reducing the quality of the fiber. Therefore, stems should be flattened immediately along their entire technical length at the earliest stages simultaneously with the pulling of flax, without flattening only the remaining part of the total length of plants, on which seed pods are located.
 RESULTS: It has been found that the size of the flattening zone in the plant ribbon is not constant. Therefore, in order to reduce the likelihood of damage to seed bolls by flattening rollers with maintaining the high accuracy of the implementation of the proposed method, it is necessary to place the upper edge of the flattening rollers at the level of the upper limit of the technical length of plants, to form a stem stand, uniform in height, with a compact area of seed bolls, reduce the galloping of flax harvesters when moving over irregularities of field surface and use such working bodies that provide the minimum longitudinal shift of the stems in the formed ribbon.
 CONCLUSIONS: An analysis of the existing means of mechanization showed that preference should be given to the TLP-1.5K trailed flax puller, which is lighter and cheaper and should be equipped with a flattening machine, in order to implement the proposed method.

Manuka Honey Reduces the Virulence of Pectobacterium brasiliense by Suppressing Genes That Encode Plant Cell Wall-Degrading Enzymes

The primary virulence of soft rot pectobacteria, including Pectobacterium brasiliense, is mainly determined by the massive production of plant cell wall-degrading enzymes (PCWDEs), which promote plant tissue maceration in many crops. The antibiotic treatment to treat bacterial soft rot causes environmental problems and potentially affects resistance. Antibiotic resistance is driving interest in antimicrobial treatments, and no organism has been reported to have acquired resistance to honey. However, the use of honey as a therapeutic agent for plant bacterial pathogens has rarely been studied. Therefore, this study was undertaken to determine the in vitro effect of Manuka honey against P. brasiliense at the phenotypic and genotypic levels. A sublethal concentration of honey was determined by a growth inhibition assay in broth medium containing different concentrations of Manuka honey. A macerating assay was performed on orchid leaves, and the activities of the PCWDEs were examined in plate assays. The expression of PCWDE-associated genes was investigated using semi-quantitative reverse transcription-polymerase chain reaction analysis. The exposure of P. brasiliense to a sublethal concentration of Manuka honey significantly decreased the maceration ability of the orchid and the synthesis of PCWDEs, i.e., pectate lyase, polygalacturonase, and protease. Moreover, five PCWDEs-encoding genes, such as pelA, pelB, pelC, pehA, and prtW, had lower expression levels after the honey treatment compared with recA as the internal standard. The honey treatment decreased the virulence of P. brasiliense associated with the synthesis of PCWDEs. Therefore, Manuka honey reduced virulence by suppressing the expression of the PCWDE genes.

Оптимизация методики получения протопластов кукурузы и их нативность после электропорации

We optimizes the composition and concentration of the enzymes, the time for enzymatic treatment and the volume of the enzyme mixture. We also optimized the concentration osmotic of agent, the centrifugation mode, and filter pore size for protoplasts isolating from epidermal cells of maize roots (Zea mays L.) of the Brown Marker (BM) line. It was found that 150 minutes is the optimal time for 150 mg root tissue maceration. The yield of intact protoplasts was ~ 4.4 ± 0.2 × 105 cells/mL at the following concentrations of enzymes and osmotic stabilizer: cellulase – 17,4, pectolase – 1.2, hemicellulase – 0.07, D-mannitol – 9.3%. The the concentration of protoplasts was to 23 times higher (p < 0.05) in 800 μl, compared with 200 μl of the enzyme mixture with equal concentrations of enzymes and osmotic stabilizer. It was found that filtration of 800 μl protoplast suspension through a filter with a pore size of 15 × 15 microns increases the yield of protoplasts up to 3.3 times, compared with a filter with a pore size of 15×39. Fractional centrifugation without preliminary filtration of the solution and the flotation method did not produce an increase in the yield of protoplasts. The residual number and protoplast wholeness after ~ 20 hours at +3 °C incubation was evaluated. The protoplast number decreased up to 2 times (p < 0.05) after electroporation.

Maceration stage in corrosion cast specimen procedure in anatomy: a minireview.

The etching stage of the corrosive preparation is a crucial element of creating a high quality anatomical specimen, which can be a source of scientific knowledge and support the teaching process. Nowadays, thermal techniques such as microwave cooking, enzymatic corrosion, and chemical corrosion are used. Living organisms can also be used for tissue maceration. Interactions between the corrosive substance and the filler carry a risk of failure; thus, choosing the correct method is key to the success of this technique. In this paper, we have reviewed the latest literature in order to present the strengths and weaknesses of currently used corrosion techniques. We proposed a definition of an ideal corrosive medium and compared the available techniques of etching corrosive preparations with a hypothetical perfect medium.

Vacuum-Sealed Hot Water Bath Immersion for the Preparation of Anatomical and Surgical Cadaveric Bone Models

Bone models serve many purposes, including improving anatomical understanding, preoperative surgical planning, and intraoperative referencing. Several techniques for the maceration of soft tissues have been described, mainly for forensic analysis. For clinical research and medical use, these methods have been superseded by three-dimensional (3D) printed models, which require substantial equipment and expertise, and are costly. Here, cadaveric sheep vertebral bone was cleaned by vacuum sealing the specimen with commercial dishwashing detergent, immersing in a hot water bath, and subsequently manually removing the soft tissue. This eliminated the disadvantages of the previously existing maceration methods, such as the existence of foul odors, usage of hazardous chemicals, substantial equipment, and high costs. The described technique produced clean, dry samples while maintaining anatomical detail and structure to accurately model the osseous structures that can be useful for preoperative planning and intraoperative referencing. The method is simple, low-cost, and effective for bone model preparation for education and surgical planning in veterinary and human medicine.

A novel bacterial strain Burkholderia sp. F25 capable of degrading diffusible signal factor signal shows strong biocontrol potential.

Vast quantities of synthetic pesticides have been widely applied in various fields to kill plant pathogens, resulting in increased pathogen resistance and decreased effectiveness of such chemicals. In addition, the increased presence of pesticide residues affects living organisms and the environment largely on a global scale. To mitigate the impact of crop diseases more sustainably on plant health and productivity, there is a need for more safe and more eco-friendly strategies as compared to chemical prevention. Quorum sensing (QS) is an intercellular communication mechanism in a bacterial population, through which bacteria adjust their population density and behavior upon sensing the levels of signaling molecules in the environment. As an alternative, quorum quenching (QQ) is a promising new strategy for disease control, which interferes with QS by blocking intercellular communication between pathogenic bacteria to suppress the expression of disease-causing genes. Black rot caused by Xanthomonas campestris pv. campestris (Xcc) is associated with the diffusible signal factor (DSF). As detailed in this study, a new QQ strain F25, identified as Burkholderia sp., displayed a superior ability to completely degrade 2 mM of DSF within 72h. The main intermediate product in the biodegradation of DSF was identified as n-decanoic acid, based on gas chromatography-mass spectrometry (GC-MS). A metabolic pathway for DSF by strain F25 is proposed, based on the chemical structure of DSF and its intermediates, demonstrating the possible degradation of DSF via oxidation-reduction. The application of strain F25 and its crude enzyme as biocontrol agents significantly attenuated black rot caused by Xcc, and inhibited tissue maceration in the host plant Raphanus sativus L., without affecting the host plant. This suggests that agents produced from strain F25 and its crude enzyme have promising applications in controlling infectious diseases caused by DSF-dependent bacterial pathogens. These findings are expected to provide a new therapeutic strategy for controlling QS-mediated plant diseases.

Effect of soaking and air-resting on the phytochemical, antioxidant, and antimicrobial properties of Piper guineense (Schum and Thonn) seeds.

Soaking and air-resting are processing steps in malting. This has been reported to increase metabolic and enzyme activities in rice paddy as a result of exposure of the grain to atmospheric oxygen. The present study evaluated the effect of soaking and air-resting on the phytochemical composition of Piper guineense seeds. The seed extracts were prepared by: soaking the seeds in water for 4 h; air-resting for 30, 60, 90, and 120 min; and re-soaking for another 4 h. The out-of-steep seeds were milled and an extract was formed by tissue homogenization and maceration using ethanol. The phytochemical, antioxidant, and antibacterial properties of the seed extract were determined using standard methods. The alkaloid, flavonoid, saponin, tannin, and total phenol contents were 0.126-0.268, 0.091-0.172, 0.080-0.123, 0.00-0.107, and 0.447-0.908 g kg-1 respectively. The antioxidant properties (reducing power) of the seed extracts were concentration-dependent and were in the range 1.08-3.24 g kg-1 at 8mg mL-1 , 1.14-3.47 g kg-1 at 16 mg mL-1 , 1.30-3.35 g kg-1 at 24 mg mL-1 , 1.26-3.11 g kg-1 at 32 mg mL-1 , and 1.13-3.04 g kg-1 at 40 mg mL-1 , respectively. The antibacterial activities against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa showed that, at 100 mg mL-1 , the inhibition zone diameters of the seed extracts were in the range 10-23 mm. Soaking and air-resting of P.guineense seeds increased the phytochemical components of the seeds. The extracts from the seeds air-rested for 30 min showed the highest phytochemical contents and had the highest antioxidant and antimicrobial properties. © 2022 Society of Chemical Industry.

Diversity and Bioactivity of Endophytic Actinobacteria Associated with Grapevines

Grapevine trunk diseases (GTDs) are a significant problem for New Zealand viticulture. Endophytic actinobacteria are of interest as potential biocontrol agents due to their ability to inhibit plant pathogens and improve plant growth. However, no studies have investigated the diversity of actinobacteria associated with grapevines in New Zealand vineyards and their bioactivity. Actinobacteria diversity in different ‘Sauvignon blanc’ vine tissues from three vineyards (conventional and organic management, and different vine ages) was assessed using different methods and media. Forty-six endophytic actinobacteria were isolated, with more isolates recovered from roots (n = 45) than leaves (n = 1) and shoot internodes (n = 0). More isolates were recovered from the organic (n = 21) than conventional (n = 8) vineyard, mature (25-year old; n = 21) than young (2-year old; n = 2) vines and using a tissue maceration technique (n = 40). Actinomycete Isolation Agar, International Streptomyces Project 2, and Starch Casein media were effective for actinobacteria isolation. Most of the isolates recovered belonged to Streptomyces, with one isolate identified as Mycolicibacterium. Forty isolates were assessed for antifungal activity and plant growth-promoting (PGP) characteristics. Of these, 13 isolates had antifungal activity against test GTD pathogens (Dactylonectria macrodidyma, Eutypa lata, Ilyonectria liriodendri, Neofusicoccum parvum, and N. luteum). Eighteen isolates exhibited more than one PGP trait; 25siderophore production (n = 25), phosphate solubilization (n = 6), and indole acetic acid production (n = 16). Two strains, Streptomyces sp. LUVPK-22 and Streptomyces sp. LUVPK-30, exhibited the best antifungal and PGP properties. This study revealed the diversity of culturable endophytic actinobacteria from grapevines in New Zealand vineyards and their biocontrol potential against GTD pathogens.

Lytic phages display protective effects against soft rot-causing Pectobacterium sp.

ABSTRACT Soft rot caused by Pectobacterium sp. is responsible for significant losses in vegetable production worldwide. Methods for the effective control of soft rot are limited and primarily based on good agricultural practices. The use of bacteriophages as biocontrol agents appears to be a promising alternative to combat phytopathogens. In this study, we investigated the efficacy of lytic phages recovered from symptomatic cabbage tissues and environmental samples against soft rot caused by Pectobacterium carotovorum subsp. carotovorum. Three bacteriophage isolates, designated as vB_PcaP-A3, vB_PcaM-D1, and vB_PcaM-J3, were observed to effectively lyse P. carotovorum subsp. carotovorum. Phage vB_PcaP-A3 exhibited virion morphology similar to the members of the podovirus group, while phages vB_PcaM-D1 and vB_PcaM-J3 showed myovirus morphology based on transmission electron microscopy. The optimal multiplicity of infection (MOI) differed greatly among the three phages. All three phages survived incubations at 30, 40 and 50 °C and pH conditions ranging from 3.0 to 9.0, but were all inactivated at 60°C and at pH 12. Both monophage and cocktail preparations were effective in inhibiting the growth of P. carotovorum subsp. carotovorum in the in vitro challenge tests. In the potato slice assays, while treatment with cocktail preparations completely inhibited the development of soft rot in tissue slices, monophage treatments not only resulted in a significant reduction of tissue maceration in slices, but also showed protective effect against soft rot in tubers. Overall, these results demonstrate the efficacy of phages vB_PcaP-A3, vB_PcaM-D1, and vB_PcaM-J3 for the biocontrol of soft rot caused by P. carotovorum subsp. carotovorum.