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Aims The immense therapeutic value of Valeriana jatamansi is attributed to the presence of bioactive secondary metabolites (valepotriates and sesquiterpenoids). Its over-exploitation in wild habitats resulted in extensive depletion, necessitating alternative approaches to produce its therapeutic metabolites. This study sought to assess the ability of endophytes of V. jatamansi to boost the biosynthesis of secondary metabolites in the leaf-cell suspension (LCS) culture of V. jatamansi. Methods and results A total of 11 fungal endophytes were isolated from the rhizomes of V. jatamansi. Isolated endophytes were found to belong to phylum Ascomycota, Basidiomycota, and Mucoromycota. Supplementation of extracts of endophyte Phaeosphaeriaceae sp. VRzFB, Mucor griseocyanus VRzFD, Penicillium raistrickii VRzFK, and Penicillium sajarovii VRzFL in the LCS culture of V. jatamansi increased the fresh cell biomass by 19.6%–39.1% and dry cell biomass by 23.4%–37.8%. Most of the endophytes' extract could increase the content of valepotriates (26.5%–76.5% valtrate and 40.5%–77.9% acevaltrate) and sesquiterpenoids (19.9%–61.1% hydroxyl valerenic acid) in LCS culture. However, only two endophytes, Irpex lacteus VRzFI and Fusarium oxysporum VRzFF, could increase the sesquiterpenoids acetoxy valerenic acid (36.9%–55.3%). In contrast, some endophytes' extracts caused negative or no significant effect on the cell biomass and targeted metabolites. Increased secondary metabolites were corroborated with increased expression of iridoid biosynthesis genes in LCS culture. Production of H2O2 and lipid peroxidation was also varied with different endophytes indicating the modulation of cellular oxidative stress due to endophyte elicitors. Conclusions The results suggest the distinct effect of different fungal endophytes-extract on LCS culture, and endophytes can serve as biotic elicitors for increasing the secondary metabolite production in plant in vitro systems. [ABSTRACT FROM AUTHOR]

Endophytic symbioses between plants and fungi are a dominant feature of many terrestrial ecosystems, yet little is known about the signaling that defines these symbiotic associations. Hydrogen peroxide (H2O2) is recognized as a key signal mediating the plant adaptive response to both biotic and abiotic stresses. However, the role of H2O2 in plant–fungal symbiosis remains elusive. Using a combination of physiological analysis, plant and fungal deletion mutants, and comparative transcriptomics, we reported that various environmental conditions differentially affect the interaction between Arabidopsis and the root endophyte Phomopsis liquidambaris , and link this process to alterations in H2O2 levels and H2O2 fluxes across root tips. We found that enhanced H2O2 efflux leading to a moderate increase in H2O2 levels at the plant–fungal interface is required for maintaining plant–fungal symbiosis. Disturbance of plant H2O2 homeostasis compromises the symbiotic ability of plant roots. Moreover, the fungus-regulated H2O2 dynamics modulate the rhizosphere microbiome by selectively enriching for the phylum Cyanobacteria, with strong antioxidant defenses. Our results demonstrated that the regulation of H2O2 dynamics at the plant–fungal interface affects the symbiotic outcome in response to external conditions and highlight the importance of the root endophyte in reshaping the rhizosphere microbiota. [ABSTRACT FROM AUTHOR]

Microbial communities associated with plants growing in harsh conditions, including salinity and water deficiency, have developed adaptive features which permit them to grow and survive under extreme environmental conditions. In the present study, an ex-situ plant trapping method has been applied to collect the culturable microbial diversity associated with the soil from harsh and remote areas. Oryza sativa cv. Baldo and Triticum durum Primadur plants were used as recruiters, while the soil surrounding the roots of Oryza glaberrima plants from remote regions of Mali (West Africa) was used as substrate for their growth. The endophytic communities recruited by the two plant species belonged to Proteobacteria and Firmicutes, and the dominant genera were Bacillus, Kosakonia , and Enterobacter. These endophytes were characterized by analyzing some of the most common plant growth promoting traits. Halotolerant, inorganic phosphate-solubilizing and N-fixing strains were found, and some of them simultaneously showing these three traits. We verified that 'Baldo' recruited mostly halotolerant and P-solubilizers endophytes, while the endophytes selected by 'Primadur' were mainly N-fixers. The applied ex-situ plant trapping method allowed to isolate endophytes with potential beneficial traits that could be applied for the improvement of rice and wheat growth under adverse environmental conditions. [ABSTRACT FROM AUTHOR]

Aims The work presented here was conducted to characterize the biodiversity of a collection of bacterial isolates, mainly wood endophytes, as part of a research project focused on exploring their bioprotective potential for postharvest biological control of fruits. Methods and results This work was the basis for the development of a tailored method combining 16S rDNA sequencing and Rep-PCR to differentiate the isolates and identify them to genus level or below. More than one hundred isolates obtained from wood and roots of different grapevine genotypes were cultured on appropriate growth media and then subjected to the specified multistep molecular identification. Conclusions We have obtained good dereplication for grapevine-endophytic bacteria, together with reliable genetic identification. Both are essential prerequisites to properly characterize a biome bank and, at the same time, beneficial prerequisites to subsequently perform a correct bioprotection assessment. [ABSTRACT FROM AUTHOR]

Endophytic microorganisms associated with medicinal plants are of particular interest as they are a potential source of new bioactive chemicals effective against novel emerging and drug-resistant pathogens. Agave americana is a tropical medicinal plant with antibacterial, antifungal, and anticancer properties. We studied the biodiversity of fungal endophytes of A. americana and their antimicrobial production potential. Isolated endophytic fungi were classified into 32 morphotypes (15 from stem and 17 from leaf) based on their cultural and morphological characteristics. Among the fungal crude extracts tested, 82% of isolates from the leaves and 80% of the isolates from the stem showed antibacterial activity against the bacterial strains (Escherichia coli ATTC 25902, Staphylococcus aureus ATTC 14775, and Bacillus subtilis NRRL 5109) tested. Extracts from four fungal isolates from leaves showed antifungal activity against at least one of the fungal strains (Candida albicans ATTC 10231 and Aspergillus fumigatus NRRL 5109) tested. Crude extracts of seven fungal isolates showed a zone of inhibition of more than 11 mm at 10 mgml-1 against both Gram-positive and Gram-negative bacteria tested. Penicillium, Colletotrichum, Curvularia, Pleosporales, Dothideomycetes , and Pleurotus are the main endophytes responsible for bioactive potential. These results indicate that A. americana harbors endophytes capable of producing antimicrobial metabolites. [ABSTRACT FROM AUTHOR]

Plant-associated microbes, specifically fungal endophytes, augment the ability of many grasses to adapt to extreme environmental conditions. Tripsacum dactyloides (Eastern gamagrass) is a perennial, drought-tolerant grass native to the tallgrass prairies of the central USA. The extent to which the microbiome of T. dactyloides contributes to its drought tolerance is unknown. Ninety-seven genotypes of T. dactyloides were collected from native populations across an east–west precipitation gradient in Kansas, Oklahoma and Texas, and then grown together in a common garden for over 20 years. Root and leaf samples were visually examined for fungal density. Because fungal endophytes confer drought-tolerant capabilities to their host plants, we expected to find higher densities of fungal endophytes in plants from western, drier regions, compared to plants from eastern, wetter regions. Results confirmed a negative correlation between endophyte densities in roots and precipitation at the genotype's original location (r  = −0.21 P  = 0.04). Our analyses reveal that the host genotype's origin along the precipitation gradient predicts the absolute abundance of symbionts in the root, but not the relative abundances of particular organisms or the overall community composition. Overall, these results demonstrate that genetic variation for plant–microbe interactions can reflect historical environment, and reinforce the importance of considering plant genotype in conservation and restoration work in tallgrass prairie ecosystems. [ABSTRACT FROM AUTHOR]

Bacteria from the leaf surface and the leaf tissue have been attributed with several beneficial properties for their plant host. Though physically connected, the microbial ecology of these compartments has mostly been studied separately such that we lack an integrated understanding of the processes shaping their assembly. We sampled leaf epiphytes and endophytes from the same individuals of sugar maple across the northern portion of its range to evaluate if their community composition was driven by similar processes within and across populations differing in plant traits and overall abiotic environment. Leaf compartment explained most of the variation in community diversity and composition across samples. Leaf epiphytic communities were driven more by host and site characteristics than endophytic communities, whose community composition was more idiosyncratic across samples. Our results suggest a greater importance of priority effects and opportunistic colonization in driving community assembly of leaf endophytes. Understanding the comparative assembly of bacterial communities at the surface and inside plant leaves may be particularly useful for leveraging their respective potential for improving the health of plants in natural and anthropized ecosystems. [ABSTRACT FROM AUTHOR]

Aims: This study aimed to isolate and characterize endophytic plant growth-promoting (PGP) actinomycetes from the wild medicinal plant Zygophyllum album. Methods and results: Eight actinomycetes were isolated, identified, and screened for their PGP activities to improve the growth and production of wheat plants under low N-inputs. Based on 16S rRNA analysis, the isolated actinobacteria showed high diversity and had multiple in vitro PGP attributes. In pot experiments, Streptomyces sp. NGB-Act4 and NGB-Act6 demonstrated the highest significant PGP activities to enhance the growth of wheat plants under reduced N-inputs. Under various field conditions (high-fertility clay soils and low-fertility sandy soils), in combination with 50% N-dose, the two streptomycetes showed significant increases in grain N% and grain yield of the wheat crop compared with the 50% N-fertilized treatment. Irrespective of soil type, wheat plants inoculated with strain NGB-Act4 produced grain yield and grain N% significantly greater than or comparable to the full N-dose treatment. Conclusions: This is the first field report on the successful use of endophytic streptomycetes as an effective strategy to improve wheat yield and reduce the use of synthetic N fertilizers. [ABSTRACT FROM AUTHOR]

The roots of the medicinal plant Codonopsis pilosula (Franch.) Nannf (C. pilosula) possess most medicinal supplements. In current research on C. pilosula root endophytes were isolated, identified, and evaluated for their antimicrobial activity against human pathogens such as Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Salmonella typhi , and Pseudomonas aeruginosa and the fungi Candida albicans and Aspergillus niger. Endophytes C.P-8 and C.P-20 exhibited very significant antimicrobial activity, the secondary metabolite of C.P-8 registered at retention time 24.075 by HPLC analysis. Significant minimum inhibitory concentration (MIC) of C.P-8 was exhibited at 250 µg/ml against S. aureus and 500 µg/ml against B. subtilis. Qualitative, quantitative analyses, and partial purification of enzymes and purity was analysed by molecular weight determined by SDS‒PAGE of enzymes produced by C.P-20, amylase—64 kDa, protease—64 kDa, chitinase—30 kDa, and cellulase—54 kDa. Optimum pH and temperature of the partially purified enzymes, was carried out. The partially purified enzymes from C.P-20 displayed maximum activity at pH 6–7 and temperatures of 40°C–45°C. Moreover, the above endophytes will be useful tools for producing active enzymes and active bioantimicrobial agents against human pathogens. [ABSTRACT FROM AUTHOR]

Due to the rise in bacterial resistance towards various therapeutic agents, interest is now developing towards fatty acid based antimicrobials because of their non-specific mode of action. A strain SORS 24 isolated from Sonchus oleraceus (Sow thistle) showed significant activity against Escherichia coli ATCC 25922 (25 mm), Chlorella vulgaris (20 mm), Bacillus subtilis DSM 10 (ATCC 6051) and Pseudomonas sp. (15 mm). It displayed an LC50 value of 10 µg/ml against Artemia salina (Brine shrimp) nauplii and an EC50 value of 0.8 µg/ml in the (DPPH) diphenylpicrylhydrazyl antioxidant assay. The strain also displayed genotoxicity against a PolA deficient strain, E. coli K-12 AB 3027 (15 mm). Mass spectrometry (HPLC-MS) showed that the strain produced oleamide (9-Octadecenamide) and erucamide (13-Docosenamide). Both of the purified fatty acid amides showed prominent activity against B. subtilis DSM 10 (ATCC 6051) (20 mm) and E. coli ATCC 25922 (15 mm). Significant genotoxicity was observed against E. coli K-12 AB 3027 (15 mm). The 16S gene sequencing revealed that the strain belonged to species, Streptomyces tanashiensis. As far as our understanding, this is the first report of this species producing these fatty acid based antimicrobials. [ABSTRACT FROM AUTHOR]

Aims Elucidating the identity of an isolate of Aspergillus sp. obtained during searches for anti-coffee leaf rust (CLR) biocontrol agents, from healthy coffee berry samples, preliminarily verify whether it is an aflatoxin-producer, confirm its ability to grow as an endophyte in healthy coffee tissues and assess its biocontrol potential against CLR. Methods and results One, among hundreds of fungal isolates fungus were obtained from healthy coffee tissues belonged to Aspergillus (isolate COAD 3307). A combination of morphology features and molecular analyses; including four regions—internal transcribed spacer, second-largest subunit of RNA polymerase (RPB2), β-tubulin (BenA) and calmodulin (CAL)—identified COAD 3307 as Aspergillus flavus. Inoculations of healthy Coffea arabica with COAD 3307 confirmed its establishment as an endophyte in leaves, stems, and roots. Treatment of C. arabica plants by combinated applications of COAD 3307 on aerial parts and in the soil, significantly (P  > .0001) reduced CLR severity as compared to controls. Thin-layer chromatography indicated that COAD 3307 is not an aflatoxin-producing isolate. In order to confirm this result, the extract was injected into high-performance liquid chromatography system equipped with a fluorescence detector, and no evidence of aflatoxin was found. Conclusions COAD 3307 is an endophytic isolate of A. flavus —a species that has never been previously recorded as an endophyte of Coffea spp. It is a non-aflatoxin producing strain that has an anti-CLR effect and merits further evaluation as a biocontrol agent. [ABSTRACT FROM AUTHOR]

During the last few decades, endophytes have attracted increased attention due to their ability to produce a plethora of bioactive secondary metabolites. These compounds not only help the endophytes to outcompete other plant-associated microbes or pathogens through quorum sensing, but also enable them to surmount the plant immune system. However, only a very few studies have described the interlink between various biochemical and molecular factors of host-microbe interactions involved in the production of these pharmacological metabolites. The peculiar mechanisms by which endophytes modulate plant physiology and metabolism through elicitors, as well as how they use transitional compounds of primary and secondary metabolism as nutrients and precursors for the synthesis of new compounds or enhancing existing metabolites, are still less understood. This study thus attempts to address the aspects of synthesis of such metabolites used in therapeutics by the endophytes in the light of their ecological significance, adaptation, and intercommunity interactions. Our study explores how endophytes adapt to the specific host environment, especially in medicinal plants that produce metabolites with pharmacological potential and simultaneously modulate host gene expression for the biosynthesis of these metabolites. We also discuss the differential interactions of fungal and bacterial endophytes with their hosts. [ABSTRACT FROM AUTHOR]

The Ascomycota form the largest phylum in the fungal kingdom and show a wide diversity of lifestyles, some involving associations with plants. Genomic data are available for many ascomycetes that are pathogenic to plants, but endophytes, which are asymptomatic inhabitants of plants, are relatively understudied. Here, using short- and long-read technologies, we have sequenced and assembled genomes for 15 endophytic ascomycete strains from CABI's culture collections. We used phylogenetic analysis to refine the classification of taxa, which revealed that 7 of our 15 genome assemblies are the first for the genus and/or species. We also demonstrated that cytometric genome size estimates can act as a valuable metric for assessing assembly "completeness", which can easily be overestimated when using BUSCOs alone and has broader implications for genome assembly initiatives. In producing these new genome resources, we emphasise the value of mining existing culture collections to produce data that can help to address major research questions relating to plant–fungal interactions. [ABSTRACT FROM AUTHOR]

Blueberry is a shallow root plant in which the absorption of nutrients is inefficient, resulting in slow growth under artificial cultivation conditions. Endophytes play an important role in promoting plant growth; however, the effects of Trichoderma spp. and dark septate endophytes (DSEs) on host plant growth and soil microorganisms are still debatable. We isolated two endophytic fungal species, Trichoderma koningiopsis (TK) and a DSE (Amesia nigricolor ; AN), from blueberry roots, which can solubilize insoluble phosphorus and produce amylase and cellulase to promote plant growth. We found that under dual inoculation, the colonization rate and colonization intensity of TK were higher than they were under single inoculation with TK, while the colonization rate and colonization intensity of AN were lower under dual inoculation than under single inoculation with AN. The plant nutrients, root activity, available potassium, and parts of soil phosphatase activities were highest under dual inoculation. TK inoculation resulted in the highest diversity and richness in the soil fungi and bacteria, followed by dual inoculation. The abundance of Ascomycota, Acidobacteriae, Firmicutes, and Actinobacteriota increased significantly, resulting in Trichoderma and Vicinamibacteria inoculated with TK, Chaetomium and Alicyclobacillales inoculated with AN, and Hypocreales and Burkholderiacea e with dual inoculation enriched in the soil. [ABSTRACT FROM AUTHOR]

In recent decades, scientists have recognized that plants' distinct and immensely dynamic microbial communities are more than just "passengers," but instead, play an important role in their development, and shielding against abiotic and biotic stresses. Endophytes comprise fungi and bacteria that live within plant tissues and support growth when plants are under stress. All plants in nature are considered to have symbiotic association with endophytes. A comprehensive review of the accessible data suggests that mobility, cell-wall degradation capacity, and reactive oxygen species scavenging are critical attributes for the successful colonization of endophytes. Plants encounter several abiotic stresses caused by climate change and global warming, which have an effect on their growth and production. Abiotic stress like high temperature, salinity, and high precipitation can severely affect plants compared to biotic stress. This review aims to highlight what role endophytes play to aid plant growth under abiotic stress conditions like heat, salinity, and drought. In the current review, we discuss how endophytic microbes can be efficiently used for the improvement and promotion of plant growth and crop production under abiotic stress conditions. [ABSTRACT FROM AUTHOR]

Many grasses are infected by systemic fungal endophytes that occur in aboveground plant tissues. Both aboveground endophytic fungi and belowground soil microbes can influence plant growth, but studies on their simultaneous effects on plant growth and competitiveness are limited. This study aims to investigate whether the role of aboveground endophytic fungi in the growth and competitive ability of the host grasses was influenced by soil microbes. In this study, we used Epichloë endophyte-infected and endophyte-free Achnatherum sibiricum as plant materials. A wet sieving method was adopted to obtain microbial inocula with different diversities (com, combined microbe fraction, high diversity; sm, small microbe fraction, low diversity). A three-factor randomized block design was used. The first factor was the endophyte infection status of A. sibiricum. The second factor was the microbial composition of the soil inocula. The third factor was the planting type. Growth and competitive characters were measured after 16 weeks. The results showed that a soil microbe inoculation was detrimental to the growth of A. sibiricum. Epichloë endophytes significantly mitigated the inhibitory effect of soil microbes on A. sibiricum planted alone. When A. sibiricum was planted with Stipa grandis , there was a significant interaction between Epichloë endophytes and soil microbes on the interspecific competition of A. sibiricum. When inoculated with small microbial community fraction, Epichloë endophytes significantly improved the interspecific competitive ability of host plants. When inoculated with combined microbial community fraction, however, Epichloë endophytes had no significant effect on host competition. The results showed that the interaction between Epichloë endophytes and soil microbes contributed more to the interspecific competitive ability than either Epichloë endophytes or soil microbes alone. [ABSTRACT FROM AUTHOR]

Here, we propose that the symbiosis outcome in plants associated with endophytes can be compromised, in addition to plant resources, by the action of phytohormones and ROS that are induced by environmental stressors. Endophytes endow plant hosts with mechanisms to protect the mutualism I Epichloë i can prevent the change in the symbiosis outcome in situations of high stress levels by inducing defence-related hormone and antioxidant plant responses that increase plant fitness (e.g. [13]; [18]). Keywords: Antioxidant; endophytes; mutualism; phytohormones; plant-endophyte symbiosis; ROS EN Antioxidant endophytes mutualism phytohormones plant-endophyte symbiosis ROS 19 23 5 12/27/22 20230101 NES 230101 Plants commonly form mutualistic associations with fungal endophytes. Antioxidant, endophytes, mutualism, phytohormones, plant-endophyte symbiosis, ROS. [Extracted from the article]

The aim of this study was to develop an efficient bioinoculant for amelioration of adverse effects from chilling stress (10°C), which are frequently occurred during rice seedling stage. Seed germination bioassay under chilling condition with rice (Oryza sativa L.) cv. Tainan 11 was performed to screen for plant growth-promoting (PGP) bacteria among 41 chilling-tolerant rice endophytes. And several agronomic traits were used to evaluate the effects of bacterial inoculation on rice seedling, which were experienced for 7-d chilling stress in walk-in growth chamber. The field trials were further used to verify the performance of potential PGP endophytes on rice growth. A total of three endophytes with multiple PGP traits were obtained. It was demonstrated that Pseudomonas sp. CC-LS37 inoculation led to 18% increase of maximal efficiency of Photosystem II (PSII) after 7-d chilling stress and 7% increase of chlorophyll a content, and 64% decline of malondialdehyde content in shoot after 10-d recovery at normal temperature in walk-in growth chamber. In field trial, biopriming of seeds with strain CC-LS37 caused rice plants to increase shoot chlorophyll soil plant analysis development values (by 2.9% and 2.5%, respectively) and tiller number (both by 61%) under natural climate and chilling stress during the end of tillering stage, afterward 30% more grain yield was achieved. In conclusion, strain CC-LS37 exerted its function in increase of tiller number of chilling stress-treated rice seedlings via improvement of photosynthetic characteristics, which in turn increases the rice grain yield. This study also proposed multiple indices used in the screening of potential endophytes for conferring chilling tolerance of rice plants. [ABSTRACT FROM AUTHOR]

Aims: We compared the bacterial endophytic communities of three genetically different almond cultivars that were all grafted on the same type of rootstock, growing side by side within a commercial orchard. Methods and Results: We examined the diversity of leaf bacterial endophytes using cultivation‐independent techniques and assessed the relative abundance of bacterial families. Two of these three cultivars were dominated by Pseudomonadaceae, while the bacterial composition of the third cultivar consisted mainly of Streptococcaceae. Conclusions: The experimental set up allowed us to analyse the impact of the shoot cultivar on endophytes, minimizing the influence of rootstock, biogeography, and cultivation status. Our data suggest that the shoot cultivar can shape the leaf endophytic community composition of almond trees. Significance and Impact of the Study: Our results suggest that the shoot cultivar controls the composition of the foliar bacterial endophytic community of almonds. Overall, our results could provide a first step to develop strategies for a more sustainable almond agriculture. [ABSTRACT FROM AUTHOR]

Aim: The plant‐growth‐promoting putative competitive endophytes offer significant benefits to sustainable agriculture. The unworthy opportunistic and passenger endophytes are inevitable during the isolation of putative competitive endophytes. This study aimed to discriminate the putative competitive endophytes undoubtedly from the opportunistic and passenger endophytes. Methods and results: The newly isolated endophytes from field‐grown rice were inoculated to 5‐days old rice seedlings under gnotobiotic conditions. Re‐isolation of the inoculated strains from the root surface, inner tissues of the whole plant, root and shoot was performed after 5‐days. All the re‐isolated colonies were compared with native isolates for homology by BOX‐A1R‐based repetitive extragenic palindromic‐PCR (BOX‐PCR) and enterobacterial repetitive intergenic consensus PCR (ERIC‐PCR) DNA fingerprints. The results revealed that the putative competitive endophytes (RE25 and RE10) showed positive for re‐isolation and BOX and ERIC fingerprints for the whole plant, root and shoot. The opportunistic (RE27 and RE8) and passenger endophytes (RE44 and RE18) failed in re‐isolation either from root or shoot. The epiphytes (ZSB15 and Az204) showed negative for endophytic re‐isolation and positive for surface colonization. Conclusion: This modified procedure can discriminate the putative competitive endophytes from others. Significance and impact of the study: Eliminating the opportunistic and passenger endophytes and epiphytes early by this method would help develop endophytic inoculants to enhance rice productivity. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) cultivation differs considerably in respect of soil type, temperature, pH, organic matter, moisture regime, etc. Among these, rising atmospheric temperature due to global warming is most important as it affects grain yield drastically. Studies have shown that for every 1°C rise in temperature above wheat's optimal growing temperature range of 20–25°C, there is a decrease in 2.8 days and 1.5 mg in the grain filling period and kernel weight, respectively, resulting in wheat yield reduction by 4–6 quintal per hectare. Growing demand for food and multidimensional issues of global warming may further push wheat crop to heat stress environments that can substantially affect heading duration, percent grain setting, maturity duration, grain growth rate and ultimately total grain yield. Considerable genetic variation exists in wheat gene pool with respect to various attributes associated with high temperature and stress tolerance; however, only about 15% of the genetic variability could be incorporated into cultivated wheat so far. Thus, alternative strategies have to be explored and implemented for sustainable, more productive and environment friendly agriculture. One of the feasible and environment friendly option is to look at micro‐organisms that reside inside the plant without adversely affecting its growth, known as 'endophytes', and these colonize virtually all plant organs such as roots, stems, leaves, flowers and grains. The relationship between plant and endophytes is vital to the plant health, productivity and overall survival under abiotic stress conditions. Thus, it becomes imperative to enlist the endophytes (bacterial and fungal) isolated till date from wheat cultivars, their mechanism of ingression and establishment inside plant organs, genes involved in ingression, the survival advantages they confer to the plant under abiotic stress conditions and the potential benefits of their use in sustainable wheat cultivation. [ABSTRACT FROM AUTHOR]

The best-known plant endophytes include mainly fungi and bacteria, but there are also a few records of microalgae growing endophytically in vascular land plants, some of which belong to the genus Coccomyxa. In this study, we isolated a single-celled photosynthetic microorganism from the arsenic-tolerant shrub Acacia farnesiana , thus we hypothesized that it is an endophytic arsenic-tolerant microalga. The microorganism was identified as belonging to the genus Coccomyxa , and the observation of algal cells within the root tissues strongly suggests its endophytic nature. The alga's tolerance to arsenate (AsV) and its influence on the fitness of A. farnesiana in the presence of AsV were evaluated. Coccomyxa sp. can tolerate up to 2000 µM of AsV for periods shorter than 10 days, however, AsV-tolerance decreased significantly in longer exposure periods. The association with the microalga increased the pigment content in aboveground tissues of A. farnesiana seedlings exposed to AsV for 50 days, without changes in plant growth or arsenic accumulation. This work describes the association, probably endophytic, between an angiosperm and a microalga, confirming the ability of the genus Coccomyxa to form associations with land plants and broadening the known variety of plant endophytes. [ABSTRACT FROM AUTHOR]

Background As in most land plants, the roots of orchids (Orchidaceae) associate with soil fungi. Recent studies have highlighted the diversity of the fungal partners involved, mostly within Basidiomycotas. The association with a polyphyletic group of fungi collectively called rhizoctonias (Ceratobasidiaceae, Tulasnellaceae and Serendipitaceae) is the most frequent. Yet, several orchid species target other fungal taxa that differ from rhizoctonias by their phylogenetic position and/or ecological traits related to their nutrition out of the orchid roots (e.g. soil saprobic or ectomycorrhizal fungi). We offer an evolutionary framework for these symbiotic associations. Scope Our view is based on the 'Waiting Room Hypothesis', an evolutionary scenario stating that mycorrhizal fungi of land flora were recruited from ancestors that initially colonized roots as endophytes. Endophytes biotrophically colonize tissues in a diffuse way, contrasting with mycorrhizae by the absence of morphological differentiation and of contribution to the plant's nutrition. The association with rhizoctonias is probably the ancestral symbiosis that persists in most extant orchids, while during orchid evolution numerous secondary transitions occurred to other fungal taxa. We suggest that both the rhizoctonia partners and the secondarily acquired ones are from fungal taxa that have broad endophytic ability, as exemplified in non-orchid roots. We review evidence that endophytism in non-orchid plants is the current ecology of many rhizoctonias, which suggests that their ancestors may have been endophytic in orchid ancestors. This also applies to the non-rhizoctonia fungi that were secondarily recruited by several orchid lineages as mycorrhizal partners. Indeed, from our review of the published literature, they are often detected, probably as endophytes, in extant rhizoctonia-associated orchids. Conclusion The orchid family offers one of the best documented examples of the 'Waiting Room Hypothesis': their mycorrhizal symbioses support the idea that extant mycorrhizal fungi have been recruited among endophytic fungi that colonized orchid ancestors. [ABSTRACT FROM AUTHOR]

Actinomycetes are prolific sources of bioactive molecules. Traditional workflows including bacterial isolation, fermentation, metabolite identification and structure elucidation have resulted in high rates of natural product rediscovery in recent years. Recent advancements in multi‐omics techniques have uncovered cryptic gene clusters within the genomes of actinomycetes, potentially introducing vast resources for the investigation of bioactive molecules. While developments in culture techniques have allowed for the fermentation of difficult‐to‐culture actinomycetes, high‐throughput metabolite screening has offered plenary tools to accelerate hits discovery. A variety of new bioactive molecules have been isolated from actinomycetes of unique environmental origins, such as endophytic and symbiotic actinomycetes. Synthetic biology and genome mining have also emerged as new frontiers for the discovery of bioactive molecules. This review covers the highlights of recent developments in actinomycete‐derived natural product drug discovery. [ABSTRACT FROM AUTHOR]

Aims: Microbial endophytes produce specialized metabolites, including antibiotics and other compounds of pharmaceutical and agricultural value. This study aimed to investigate the diversity and bioactivity of endophytes from medicinal plants used by the Dharawal People of Gamay (Botany Bay), Australia. Methods and Results: Of the 48 endophytes isolated, 19 tested positive for polyketide synthase or non‐ribosomal peptide synthetase genes via a PCR incorporating degenerate primers. The biosynthetically talented endophytes were identified by 16S rRNA gene sequencing and included 4 bacteria species belonging to the orders Bacillales, Rhizobiales and Burkholderiales and 15 Ascomycota fungi species belonging to the orders Botryosphaeriales, Cladosporiales, Glomerellales, Microascales and Eurotiales. Antimicrobial testing using the disc diffusion assay demonstrated that 15 of the 19 isolates had broad‐spectrum activity against a range of Gram‐positive and Gram‐negative bacteria. Conclusions: Taken together, these results suggest that Australian bush medicines harbour diverse biosynthetically talented microbial endophytes capable of producing broad‐spectrum antibacterial compounds. Significance and Impact of the Study: This study suggests that compounds produced by microbial endophytes likely contribute to the collective medicinal properties of Australian bush medicines. Significantly, it highlights that Indigenous botanical knowledge and modern molecular approaches can be used in tandem to prioritize microorganisms that produce pharmaceutically relevant compounds. [ABSTRACT FROM AUTHOR]

Aims: This study aimed at determining the distribution, colonization and growth promoting nature of Methylobacterium spp. in tissue culture banana plantlets. Methods and Results: Leaf samples from different field grown banana cultivars were used for Methylobacterium spp., isolation. Metabolic profile and functional characterization for plant growth‐promoting traits of the isolates were assessed. The isolates were confirmed using 16S rRNA gene sequencing analysis, which resulted in six distinct species of Methylobacterium namely M. radiotolerans, M. salsuginis, M. thiocyanatum, M. rhodesianum, M. rhodinum and M. populi. Methylobacterium spp. inoculation experiment was conducted under hydroponic system in tissue culture banana plantlets (germ free) with eight selected isolates. A significant increase in growth parameters of Methylobacterium treated plantlets compared to uninoculated control was observed. Methylobacteriumsalsuginis TNMB03‐gfp29 was developed and colonization micrograph was obtained using confocal laser scanning microscopy (CLSM) and scanning electron microscopy in different parts of banana plantlets (root, stem and leaves). Conclusion: Field grown banana plants found to harbour diverse endophytic Methylobacterium population. Our finding suggests that endophytic Methylobacterium species may provide significant plant growth promoting compounds/nutrients to the banana plants. The experimental results demonstrated the efficacy of Methylobacterium spp. as a potential bioinoculant and can be exploited as a phyllosphere and rhizosphere based bioinoculant for the initial establishment and growth of tissue culture banana plantlets. Significance and Impact of the Study: This study extended our knowledge on the distribution of Methylobacterium spp. in banana plants and endophytic colonization nature of this particular genus in plants. In addition, efficient isolate (M. salsuginis TNMB03) identified in this study may be promoted as bio‐inoculants for banana plants after field evaluation. [ABSTRACT FROM AUTHOR]

Plants associate with communities of microbes (bacteria and fungi) that play critical roles in plant development, nutrient acquisition and oxidative stress tolerance. The major share of plant microbiota is endophytes which inhabit plant tissues and help them in various capacities. In this article, we have reviewed what is presently known with regard to how endophytic microbes interact with plants to modulate root development, branching, root hair formation and their implications in overall plant development. Endophytic microbes link the interactions of plants, rhizospheric microbes and soil to promote nutrient solubilization and further vectoring these nutrients to the plant roots making the soil‐plant‐microbe continuum. Further, plant roots internalize microbes and oxidatively extract nutrients from microbes in the rhizophagy cycle. The oxidative interactions between endophytes and plants result in the acquisition of nutrients by plants and are also instrumental in oxidative stress tolerance of plants. It is evident that plants actively cultivate microbes internally, on surfaces and in soils to acquire nutrients, modulate development and improve health. Understanding this continuum could be of greater significance in connecting endophytes with the hidden half of the plant that can also be harnessed in applied terms to enhance nutrient acquisition through the development of favourable root system architecture for sustainable production under stress conditions. [ABSTRACT FROM AUTHOR]

Legume root nodules harbor rhizobia and other non-nodulating endophytes known as nodule-associated bacteria (NAB) whose role in the legume symbiosis is still unknown. We analysed the genetic diversity of 34 NAB isolates obtained from the root nodules of faba bean grown under various soil conditions in Egypt using 16S rRNA and concatenated sequences of three housekeeping genes. All isolates were identified as members of the family Enterobacteriaceae belonging to the genera Klebsiella , Enterobacter and Raoultella. We identified nine enterobacterial genospecies, most of which have not been previously reported as NAB. All isolated strains harbored nifH gene sequences and most of them possessed plant growth-promoting (PGP) traits. Upon co-inoculation with an N2 fixing rhizobium (Rlv NGB-FR128), two strains (Enterobacter sichanensis NGB-FR97 and Klebsiella variicola NGB-FR116) significantly increased nodulation, growth and N-uptake of faba bean plants over the single treatments or the uninoculated control. The presence of these enterobacteria in nodules was significantly affected by the host plant genotype, symbiotic rhizobium genotype and endophyte genotype, indicating that the nodule colonization process is regulated by plant–microbe–microbe interactions. This study emphasizes the importance of nodule-associated enterobacteria and suggests their potential role in improving the effectiveness of rhizobial inoculants. [ABSTRACT FROM AUTHOR]

European apple canker, caused by Neonectria ditissima , is a severe disease of apple. Achieving effective control is difficult with the currently available pesticides. Specific apple endophytes associated with cultivars may partially contribute to the cultivar response to the pathogen and thus could be used for disease management. We sought to determine whether the overall endophyte community differed among cultivars differing in their susceptibility to N. ditissima and to identify specific microbial groups associated with the susceptibility. Using Illumina MiSeq meta-barcoding, we profiled apple tree endophytes in 16 scion–rootstock combinations at two locations and quantified the relative contribution of scion, rootstock and location to the observed variability in the endophyte communities. Endophyte diversity was primarily affected by the orchard location (accounting for 29.4% and 85.9% of the total variation in the PC1 for bacteria and fungi, respectively), followed by the scion genotype (24.3% and 19.5% of PC2), whereas rootstock effects were small (<3% of PC1 and PC2). There were significant differences in the endophyte community between canker-resistant and -susceptible cultivars. Several bacterial and fungal endophyte groups had different relative abundance between susceptible and resistant cultivars. These endophyte groups included putative pathogen antagonists as well as plant pathogens. Their possible ecological roles in the N. ditissima pathosystem are discussed. [ABSTRACT FROM AUTHOR]

Aims: To identify the metabolites produced by the endophytic fungus, Aspergillus terreus and to explore the anti‐viral activity of the identified metabolites against the pandemic disease COVID‐19 in‐silico. Methods and Results: Herein, we reported the isolation of A. terreus, the endophytic fungus associated with soybean roots, which is then subcultured using OSMAC approach in five different culture media. Analytical analysis of media ethylacetate extracts using liquid chromatography coupled with high‐resolution mass spectrometry (LC‐HRMS) was carried out. Furthermore, the obtained LC–MS data were statistically processed with MetaboAnalyst 4.0. Molecular docking studies were performed for the dereplicated metabolites against COVID‐19 main protease (Mpro). Metabolomic profiling revealed the presence of 18 compounds belonging to different chemical classes. Quinones, polyketides and isocoumarins were the most abundant classes. Multivariate analysis revealed that potato dextrose broth and modified potato dextrose broth are the optimal media for metabolites production. Molecular docking studies declared that the metabolites, Aspergillide B1 and 3a‐Hydroxy‐3, 5‐dihydromonacolin L showed the highest binding energy scores towards COVID‐19 main protease (Mpro) (−9·473) and (−9·386), respectively, and they interact strongly with the catalytic dyad (His41 and Cys145) amino acid residues of Mpro. Conclusions: A combination of metabolomics and in‐silico approaches have allowed a shorter route to search for anti‐COVID‐19 natural products in a shorter time. The dereplicated metabolites, aspergillide B1 and 3α‐Hydroxy‐3, 5‐dihydromonacolin L were found to be potent anti‐COVID‐19 drug candidates in the molecular docking study. Significance and Impact of the Study: This study revealed that the endophytic fungus, A. terreus can be considered as a potential source of natural bioactive products. In addition to, the possibility of developing the metabolites, aspergillide B1 and 3α‐Hydroxy‐3, 5‐dihydromonacolin L to be used as phytopharmaceuticals for the management of COVID‐19. [ABSTRACT FROM AUTHOR]

Wild berries are interesting research subjects due to their rich sources of health-beneficial phenolic compounds. However, the internal microbial communities, endophytes, associated with the wild berry fruits are currently unknown. Endophytes are bacteria or fungi inhabiting inside plant tissues, and their functions vary depending on the host species and environmental parameters. The present study aimed to examine community composition of fungal and bacterial endophytes in fruits of three wild berry species (bilberry Vaccinium myrtillus L. lingonberry Vaccinium vitis-idaea L. and crowberry Empetrum nigrum L.) and the effects of host plant species and their growth sites on shaping the endophytic communities. We found that the endophytic community structures differed between the berry species, and fungi were predominant over bacteria in the total endophytic taxa. We identified previously unknown endophytic fungal taxa including Angustimassarina , Dothidea , Fellozyma , Pseudohyphozyma , Hannaella coprosmae and Oberwinklerozyma straminea. A role of soluble phenolic compounds, the intracellular components in wild berry fruits, in shaping the endophytic communities is proposed. Overall, our study demonstrates that each berry species harbors a unique endophytic community of microbes. [ABSTRACT FROM AUTHOR]

Seed borne microorganisms play an important role in plant biology. Concerns have recently been raised about loss of seed microbial diversity by seed treatments, crop domestication and plant breeding. Information on the seed microbiomes of native plants growing in natural ecosystems is beneficial as they provide the best settings to detect indigenous plant microbe interactions. Here, we characterized the seed bacterial community of 8 native alpine grassland plants. First, seed bacterial diversity was examined using Illumina DNA sequencing, then 28 cultivable bacteria were isolated and potential functions were explored. Across 8 plant species, 343 different bacterial genera were identified as seed endophytes, 31 of those were found in all plant species, indicating a high level of conservation. Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes and Chloroflexi were the top five dominant phyla. Plant species identity was a key determinant shaping the seed endophytic bacteriome. ACC deaminase activity, siderophores production and secretion of lytic enzymes were common functions shown by isolated bacteria. Our results demonstrate that highly diverse and beneficial bacterial populations are hosted by seeds of alpine grassland species to ensure the establishment of best bacterial symbionts for the next generation. This information is useful for crop improvement by reinstating beneficial seed microbial diversities for high-quality forage and crop seeds. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the production of biosurfactants by fungi isolated from the Amazonian species Piper hispidum (Piperaceae), and to determine the physico‐chemical properties of the crude biosurfactant obtained from the most promising fungi. Methods and Results: A total of 117 endophytic fungi were isolated, and 50 were used to verify the production of biosurfactants. Of these, eight presented positive results in the drop collapse test, and emulsification index ranging from 20 to 78%. The most promising fungi, Ph III 23L and Ph II 22S (identified as Aspergillus niger and Glomerella cingulata, respectively) were recultivated for extraction and analysis of the biosurfactant's physico‐chemical characteristics. The cultivation broth that presented the greatest decrease in surface tension (36%) was that of the A. niger, which reduced it from 68·0 to 44·0 mN m−1. The lowest critical micellar concentration value was found for the same endophyte (14·93 mg ml−1). Conclusions: Endophytes of P. hispidum proved to be interesting producers of biosurfactants and presented promising physico‐chemical characteristics for applications in diverse industrial sectors. Significance and Impact of the Study: Piper hispidum endophytic fungi can be used as a new source of biosurfactants, as these molecules present a significant market due to their wide industrial applications. [ABSTRACT FROM AUTHOR]

Summary: Several ascomycetous insect‐pathogenic fungi, including species in the genera Beauveria and Metarhizium, are plant root symbionts/endophytes and are termed as endophytic insect‐pathogenic fungi (EIPF). The endophytic capability and insect pathogenicity of Metarhizium are coupled to provide an active method of insect‐derived nitrogen transfer to plant hosts via fungal mycelia. In exchange for the insect‐derived nitrogen, the plant provides photosynthate to the fungus. This symbiotic interaction offers other benefits to the plant—EIPF can improve plant growth, they are antagonistic to plant pathogens and herbivores and can enhance the plant tolerance to abiotic stresses. The mechanisms and underlying biochemical and genetic features of insect pathogenesis are generally well‐established. However, there is a paucity of information regarding the underlying mechanisms in this plant‐symbiotic association. Here we review five aspects of EIPF interactions with host plant roots: (i) rhizosphere colonization, (ii) signalling factors from the plant and EIPF, (iii) modulation of plant defence responses, (iv) nutrient exchange and (v) tripartite interactions with insects and other micro‐organisms. The elucidation of these interactions is fundamental to understanding this symbiotic association for effective application of EIPF in an agricultural setting. [ABSTRACT FROM AUTHOR]

The application of new agricultural technologies to attain sustainable production systems is necessary. The use of plant growth-promoting bacteria to improve plant growth and health has been studied for decades. This work aimed to isolate diazotrophic endophytic bacteria associated with sweet sorghum plants and study the interaction of their inoculation in combination with chemical N-fertilization on different sorghum cultivars. A bacterial collection of 181 isolates was constructed and characterized in vitro and in vivo. From that, the strains Enterobacter sp. UYSB89 and Kosakonia sp. UYSB139 were nifH +, produce IAA, defined as true endophytes and able to promote growth of two sweet sorghum under greenhouse conditions. The evaluated cultivars responded differentially to bacterial inoculation, the nitrogen fertilization doses and their interaction. Thus, plant growth is a multifactorial consequence of the interrelation between crop practices and the plant genotypes. This knowledge is a valuable factor in terms of understanding plant–bacteria endophyte interactions to preserve environmental sustainability during the implementation of agronomic practices. [ABSTRACT FROM AUTHOR]

This study was focus on investigating the community composition of endophytic fungi in the leaves of Vaccinium dunalianum Wight. Based on a combination of morphological features and molecular evidence, 239 endophytic fungal isolates belonging to 33 genera including 62 species were obtained and identified. By comparing the relative abundance (RA) values, the most frequent species belonged to Phyllosticta and Guignardia with RA of 26·78 and 14·22% respectively. Of which, the strains P. capitalensis and G. mangiferae with potential antimicrobial activity were the dominant endophytes to the sampling of leaves. A high diversity of endophytic fungi from V. dunalianum leaves was observed with high species richness S (62), Margalef index D′ (11·1386), Shannon–Wiener index H′ (3·2588), Simpson's diversity index Ds (0·9179), probability of interspecific encounter index (0·9218), and evenness Pielou index J (0·7896) but a low dominant index λ (0·0821). Significance and Impact of the Study: The isolated 239 endophytic fungal strains belong to 33 genera, 62 species, in which a high diversity of endophytic fungi was observed in Vaccinium dunalianum leaves. In this study, two taxa Phyllosticta capitalensis and Guignardia mangiferae with potential antimicrobial activity were the dominant endophytes. This is a promising source of natural bioactive compounds for future agro‐industry application. [ABSTRACT FROM AUTHOR]

Bacterial endophytes are found in the internal tissues of plants and have intimate associations with their host. However, little is known about the diversity of medicinal plant endophytes (ME) or their capability to produce specialised metabolites that may contribute to therapeutic properties. We isolated 75 bacterial ME from 24 plant species of the Western Ghats, India. Molecular identification by 16S rRNA gene sequencing grouped MEs into 13 bacterial genera, with members of Gammaproteobacteria and Firmicutes being the most abundant. To improve taxonomic identification, 26 selected MEs were genome sequenced and average nucleotide identity (ANI) used to identify them to the species-level. This identified multiple species in the most common genus as Bacillus. Similarly, identity of the Enterobacterales was also distinguished within Enterobacter and Serratia by ANI and core-gene analysis. AntiSMASH identified non-ribosomal peptide synthase, lantipeptide and bacteriocin biosynthetic gene clusters (BGC) as the most common BGCs found in the ME genomes. A total of five of the ME isolates belonging to Bacillus , Serratia and Enterobacter showed antimicrobial activity against the plant pathogen Pectobacterium carotovorum. Using molecular and genomic approaches we have characterised a unique collection of endophytic bacteria from medicinal plants. Their genomes encode multiple specialised metabolite gene clusters and the collection can now be screened for novel bioactive and medicinal metabolites. [ABSTRACT FROM AUTHOR]

Plants are now recognized as metaorganisms which are composed of a host plant associated with a multitude of microbes that provide the host plant with a variety of essential functions to adapt to the local environment. Recent research showed the remarkable importance and range of microbial partners for enhancing the growth and health of plants. However, plant–microbe holobionts are influenced by many different factors, generating complex interactive systems. In this review, we summarize insights from this emerging field, highlighting the factors that contribute to the recruitment, selection, enrichment, and dynamic interactions of plant-associated microbiota. We then propose a roadmap for synthetic community application with the aim of establishing sustainable agricultural systems that use microbial communities to enhance the productivity and health of plants independently of chemical fertilizers and pesticides. Considering global warming and climate change, we suggest that desert plants can serve as a suitable pool of potentially beneficial microbes to maintain plant growth under abiotic stress conditions. Finally, we propose a framework for advancing the application of microbial inoculants in agriculture. [ABSTRACT FROM AUTHOR]

Aims: This research aimed to identify factors influencing endophyte community structure in apple shoots and the bioactivity of cultured representatives against the fungal pathogen Neonectria ditissima. Methods and Results: The endophyte community in leaves and stems of the apple cultivars 'Royal Gala' and 'Braeburn' were analysed by a cultivation‐independent method (PCR‐DGGE) which showed that tissue type, cultivar and site were determinant factors, with the endophyte taxa in 'Royal Gala' more variable than that in 'Braeburn', with leaf endophyte communities typically differing from stems in both cultivars. Seasonal (spring vs autumn) and regional (Nelson vs Hawke's Bay) variations were not obvious in woody stems. A collection of 783 bacterial and 87 fungal endophytes were recovered from leaves and stems of 'Royal Gala', 'Braeburn', 'Scilate' and/or 'Scifresh' from Nelson (nine sites) and Hawke's Bay (five sites) in spring and from Nelson (three sites) in autumn. A dual culture plating assay was used to test their ability to inhibit the mycelial growth of N. ditissima. Thirteen bacterial (mean of percent inhibition ≥20%) and 17 fungal isolates were antagonistic towards N. ditissima. These isolates belonged to the bacterial genera Bacillus and Pseudomonas, and fungal genera Chaetomium, Epicoccum, Biscogniauxia, Penicillium, Diaporthe, Phlyctema and two unidentified fungal isolates. Conclusions: Endophyte communities in apple shoots were determined by tissue type, cultivar and site. Endophytic bacterial and fungal isolates inhibiting N. ditissima growth in vitro were found. Significance and Impact of the Study: These results provided new evidence of factors influencing apple endophyte community in New Zealand. Endophytes with potential to reduce N. ditissima infection were identified, with the potential to be developed into a biocontrol strategy for European canker. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the antimicrobial potential of Juglomycins isolated from Streptomyces achromogenes E91CS4, an endophyte of Crocus sativus Linn. Methods and Results: The extract from E91CS4 displayed significant antimicrobial activity against several pathogens. The endophyte was identified as S. achromogenes on by 16S ribosomal gene analysis. Chemical investigation of the extract led to the isolation of two naphthoquinone antibiotics, Juglomycin A and B. Juglomycin A inhibited several pathogens, with an MIC value of 13·7µg ml−1, whereas it was most potent against Escherichia coli, Bacillus thuringiensis and Xanthobacter flavus with MIC values of 6·8, 3·4 and 6·8 µg ml−1 respectively. It was found to reduce the biofilm formation in E. coli through inhibition of swimming and swarming motilities and downregulation of fimH gene. The α‐haemolysin‐related gene (hlyA) was also downregulated indicating that the compound is also reducing the virulence in E. coli. In vitro time kill kinetics showed efficient bactericidal activity of this compound. Furthermore, Juglomycin A inhibited bacterial transcription/translation in vitro, while also inducing postantibiotic effect in E. coli. Conclusions: Juglomycin A is a potential antimicrobial compound against several bacterial pathogens, particularly, E. coli. Significance and Impact of the Study: This study showed the promising potential of Juglomycin A as an antimicrobial agent. Efforts should be made to scale up the production of this compound and conduct further studies to explore its efficacy as an antibiotic, using in vivo models. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to identify and characterize promising endophytes capable of enhancing the content of root alkaloids ajmalicine and serpentine in low alkaloid yielding genotype of Catharanthus roseus cultivar Prabal and the possible mechanisms involved. Method and Result: Of the four strains isolated from alkaloid‐rich genotype of C. roseus cultivar Dhawal, endophytic strains CATDLF5 (Curvularia sp.) and CATDLF6 (Choanephora infundibulifera) enhanced serpentine content by 211·7–337·6%, while CATDRF2 (Aspergillus japonicus) and CATDS5 (Pseudomonas sp.) increased the content of ajmalicine by 123·4–203·8% in cultivar Prabal. Upregulated expression of key genes, geraniol 10‐hydroxylase, tryptophan decarboxylase and strictosidine synthase involved in terpenoid indole alkaloid (TIA) biosynthetic pathway was observed in endophyte inoculated plants. Upregulated Octadecanoid‐derivative Responsive Catharanthus AP2/ERF domain transcription activators like ORCA3 while, and downregulation of transcriptional repressor, ZCTs (Cys2/His2‐type zinc finger protein family) enhanced the expression of genes for secondary metabolite production in endophyte‐inoculated plants. Conclusion: The present work concluded that the selected endophytes of C. roseus can enhance the ajmalicine and serpentine contents by modulating the expression of structural and regulatory genes of TIA biosynthetic pathway in root. Significance and Impact of the Study: Endophytes can play an important role to enhance in planta content of pharmaceutically important alkaloids in C. roseus and can therefore be useful in reducing the cost of production of important alkaloids. [ABSTRACT FROM AUTHOR]

The positive effects of high atmospheric CO2 concentrations [CO2] decrease over time in most C3 plants because of down-regulation of photosynthesis. A notable exception to this trend is plants hosting N-fixing bacteria. The decrease in photosynthetic capacity associated with an extended exposure to high [CO2] was therefore studied in non-nodulating rice that can establish endophytic interactions. Rice plants were inoculated with diazotrophic endophytes isolated from the Salicaceae and CO2 response curves of photosynthesis were determined in the absence or presence of endophytes at the panicle initiation stage. Non-inoculated plants grown under elevated [CO2] showed a down-regulation of photosynthesis compared to those grown under ambient [CO2]. In contrast, the endophyte-inoculated plants did not show a decrease in photosynthesis associated with high [CO2], and they exhibited higher photosynthetic electron transport and mesophyll conductance rates than non-inoculated plants under high [CO2]. The endophyte-dependent alleviation of decreases in photosynthesis under high [CO2] led to an increase in water-use efficiency. These effects were most pronounced when the N supply was limited. The results suggest that inoculation with N-fixing endophytes could be an effective means of improving plant growth under high [CO2] by alleviating N limitations. [ABSTRACT FROM AUTHOR]

Aims: To characterize the bacterial communities of the rhizosphere and endosphere of the forage grass timothy (Phleum pratense L.) and evaluate the functional attributes with respect to growth promotion properties, antimicrobial and biosurfactant capacities. Methods and Results: A total of 254 culturable bacteria were identified using 16S rRNA sequencing and grouped into 16 taxa that shared high homology of 98–99% with other known sequences. A majority of the isolates were recovered from the rhizosphere soil fraction and leaf and crown tissues. Bacillus genus was the most abundant in the bulk and rhizosphere soil fractions. Isolates belonging to the Methylobacterium genus were exclusively found in leaves making them tissue‐specific. A majority of the bacterial isolates exhibited multi‐functional growth promotion attributes and plant stress improvement related to the production of indole 3‐acetic acid, VOC and siderophores and polymer‐degrading enzymes and 1‐aminocyclopropane‐1‐carboxylate (ACC) deaminase activities. Some demonstrated antimicrobial properties such as hydrogen cyanide and biosurfactant production and activities of fungal cell wall degrading enzymes. The internalization and spread of selected bacterial isolates in timothy seedlings under gnotobiotic conditions was confirmed using the culture‐dependent method and SEM microscopy in proof‐of‐concept experiments. Conclusions: The attributes of some isolates with respect to growth promotion abilities, biocontrol potential and efficient colonization of timothy make them desirable for future development as potential biofertilizer tools. Significance and Impact of the Study: This study provides the first evidence of bacterial endophytes that have the necessary functional attributes to protect cool‐season forage grasses against abiotic stress. [ABSTRACT FROM AUTHOR]

The objective of this experiment was to evaluate effects of extended-release eprinomectin on fescue toxicosis and impacts on performance and reproduction in fall-calving beef cows. Fall-calving Angus × Simmental multiparous cows [ n = 335; age = 5.8 ± 2.1 yr; 586.5 ± 6.0 kg body weight (BW); 5.48 ± 0.05 body condition score (BCS)] were stratified by BW, age, and BCS and randomly assigned to one of three treatments. Treatments included a spring injection of extended-release eprinomectin (SERE) on day 0, a fall injection of extended-release eprinomectin injection (FERE) on day 84, and a saline control (CON). All treatments were administered at a rate of 1 mL/50 kg BW. Prior to the experiment, all cows were treated with oral fenbendazole to minimize parasite load. Cows grazed endophyte-infected tall fescue. Hair coat score (HCS), BW, and BCS were recorded on all cattle. Fecal egg count (FEC), respiration rate (RR), horn fly and tick count, hematocrit (% packed cell volume, PCV), and serum prolactin were analyzed on a subset of cows (35/treatment). On day 194, cows were artificially inseminated (AI) and 11 d following AI were exposed to bulls for 51 d. Milk production was estimated on day 210 on a subset of 85 cow–calf pairs (28–29/treatment). There was a tendency for a treatment × time interaction (P = 0.07) for FEC likely driven by an increase in FEC of the CON cattle at day 126 compared to SERE and FERE. There was a tendency for a treatment × time interaction (P = 0.06) for cow BW, largely driven by time differences; however, there was no effect of treatment (P = 0.84) on BW. There was no difference (P ≥ 0.13) in cow PCV, fly and tick count, BCS, HCS, RR, and serum prolactin throughout the experiment. Additionally, there was no difference (P ≥ 0.46) in Julian calving date, calf birth BW, or milk production between treatments. Interestingly, heifer calves born to FERE dams tended to have greater (P = 0.06) weaning BW compared to heifer calves born to CON dams. In addition, there was no difference (P ≥ 0.17) in heat patch scores, AI conception rates, or overall pregnancy rates between treatments. Extended-release eprinomectin did not impact cow growth performance, reproductive performance or fescue toxicity symptoms when grazing endophyte-infected tall fescue; however, calf weaning BW tended to be improved. [ABSTRACT FROM AUTHOR]

The goal of this study was to test the hypothesis that sodium selenite (ISe), SEL-PLEX (OSe), vs. a 1:1 blend (MIX) of ISe and OSe in a basal vitamin-mineral mix would differentially affect serological and hepatic parameters of growing steers grazing toxic endophyte-infected tall fescue-mixed forage pasture. Predominately Angus steers (BW = 183 ± 34 kg) were randomly selected from herds of fall-calving cows grazing endophyte-infected tall fescue-mixed pasture and consuming vitamin-mineral mixes that contained 35 ppm Se as ISe, OSe, and MIX forms. Steers were weaned, depleted of Se for 98 d, and subjected to summer-long common grazing of an endophyte-infected tall fescue-mixed pasture (0.51 ppm total ergovaline + ergovalinine; 10.1 ha). Steers were assigned (n = 8 per treatment) to the same Se form treatments upon which they were raised. Se treatments were administered by daily top-dressing 85 g of vitamin-mineral mix onto 0.23 kg soyhulls, using in-pasture Calan gates. The PROC MIXED procedure of SAS was used to assess the effect of Se form treatments on serum parameters at day 0, 22, 43, 64, and 86. After slaughter, the effect of Se treatment on hepatic alkaline phosphatase (tissue nonspecific isoform, TNALP) mRNA, protein, and albumin protein content was assessed using the PROC GLM procedure of SAS. Fisher's protected LSD procedure was used to separate treatment means. Partial correlation analysis was used to evaluate the relationship among whole blood Se concentration and serum parameters, accounting for the effect of time. Across periods, MIX steers had more (P ≤ 0.04) serum albumin than OSe and ISe steers, respectively. However, the relative hepatic bovine serum albumin protein content was not affected (P = 0.28) by Se treatments. Serum alkaline phosphatase activity was greater (P ≤ 0.01) in MIX and OSe steers. Similarly, hepatic TNALP protein content in MIX steers was greater (P = 0.01) than ISe steers. Partial correlation analysis revealed that serum albumin, blood urea nitrogen, and alkaline phosphatase activity were correlated (r ≥ 0.23, P ≤ 0.02) with whole blood Se concentration. In summary, consumption of 3 mg Se/d as OSe or MIX forms of Se in vitamin-mineral mixes increased serum albumin concentration and alkaline phosphatase activity, the reduction of which is associated with fescue toxicosis. We conclude that the organic forms of Se ameliorated the depression of 2 of known serological biomarkers of fescue toxicosis. [ABSTRACT FROM AUTHOR]

Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue. The objective of this study was to evaluate the impact of the slick hair trait on physiological and reproductive parameters in heifers experiencing fescue toxicosis. Angus × Senepol heifers (n = 31) were blocked by weight (393.5 ± 17.3 kg) and phenotype relative to hair coat at birth, and randomly fed novel endophyte fescue (EN) or endophyte-infected fescue (EI) haylage in a total mixed ration for 91 d. Weekly measurements were collected to monitor heifer growth and response during ergot alkaloids exposure. Following 28 d of treatment, estrus was synchronized and heifers were inseminated. Ovary mapping and AI pregnancy rate were examined via transrectal ultrasonography. Blood samples were taken for genotyping: slick (S) or wildtype (W). Data were analyzed using repeated measures in PROC MIXED of SAS including fescue treatment (EN vs. EI), genotype (S vs. W), and sample collection time as main effects. Body condition scores were decreased for W heifers compared with S heifers (5.48 vs. 5.66, respectively; P < 0.0001). Surface temperature was greater for EI-W heifers (37.2 °C) compared with other groups (36.4, 36.6, 36.7 °C for EN-S, EN-W, EI-S, respectively; P < 0.05). Serum PRL concentrations were reduced for EI heifers compared with EN heifers (133.5 vs. 163.1 ng/mL, respectively; P < 0.05). The average number of 2 to 4 mm follicles were greater in EI-W heifers (13.8 follicles) compared with other groups (12.2, 10.6, and 11.1 for EN-S, EN-W, and EI-S, respectively; P < 0.0001). However, the average number of preovulatory follicles (≥9 mm) were reduced in EI-W heifers (0.52 follicles) compared with other heifer groups (0.94, 0.88, and 0.85 ± 0.04 for EN-S, EN-W, and EI-S, respectively; P < 0.05). Ovulatory follicle size was smaller in EI-W heifers compared with EN-W heifers (9.14 vs. 11.57 mm, respectively; P = 0.05). Corpus luteum area was reduced in EI-W heifers (235.1 mm2) compared with other heifer groups (297.2, 272.7, and 276.8 mm2 for EN-S, EN-W, and EI-S, respectively; P < 0.05). Concentrations of P4 were greater for EN heifers compared with EI heifers (2.7 vs. 1.8 ng/mL, respectively; P < 0.05). Pregnancy was not established in EI-W heifers (0%) compared with other heifer groups (37.5%, 57.1%, and 62.5% for EN-S, EN-W, and EI-S, respectively; P < 0.05). Overall, the slick hair mutation appears to aid in offsetting the physiological symptoms associated with fescue toxicosis and helps to improve reproductive performance. [ABSTRACT FROM AUTHOR]

Tall fescue [ Lolium arundinaceum (Scheyreb.) Darbysh] is the primary cool season forage grass in the Southeastern United States. Most tall fescue contains an endophytic fungus (Epichloë coenophiala) that produces ergot alkaloids and upon ingestion induces fescue toxicosis. The objective of this study was to assess how exposure to endophyte-infected (E+ ; 1.77 mg hd−1 d−1 ergovaline and ergovalinine) or endophyte-free (E- ; 0 mg hd−1 d−1 ergovaline and ergovalinine) tall fescue seed fed during 2 stages of gestation (MID, days 35–85/ LATE, days 86–133) alters placental development. Thirty-six, fescue naïve Suffolk ewes were randomly assigned to 1 of 4 fescue treatments: E−/E−, E−/E+, E+/E−, or E+/E+. Ewes were individually fed the same amount of E+ or E− seed mixed into total mixed ration during MID and LATE gestation. Terminal surgeries were conducted on day 133 of gestation. Ewes fed E+ fescue seed had elevated (P < 0.001) ergot alkaloid excretion and reduced (P < 0.001) prolactin levels during the periods when fed E+ seed. Ewes switched on day 86 from E− to E+ seed had a 4% reduction (P = 0.005) in DMI during LATE gestation, which translated to a 2% reduction (P = 0.07) in DMI overall. Average daily gain was also reduced (P = 0.049) by 64% for E−/E+ ewes during LATE gestation and tended to be reduced (P = 0.06) by 33% overall. Ewes fed E+ seed during LATE gestation exhibited a 14% and 23% reduction in uterine (P = 0.03) and placentome (P = 0.004) weights, respectively. Caruncle weights were also reduced by 28% (P = 0.003) for E−/E+ ewes compared with E−/E− and E+/E−. Ewes fed E+ seed during both MID and LATE gestation exhibited a 32% reduction in cotyledon (P = 0.01) weights, whereas ewes fed E+ seed only during MID gestation (E+/E−) had improved (P = 0.01) cotyledon weights. The percentage of type A placentomes tended to be greater (P = 0.08) for E+/E+ ewes compared with other treatments. Other placentome types (B, C, or D) did not differ (P > 0.05). Total fetal weight per ewe was reduced (P = 0.01) for ewes fed E+ seed during LATE gestation compared with E−; however, feeding E+ seed during MID gestation did not alter (P = 0.70) total fetal weight per ewe. These results suggest that exposure to ergot alkaloids during LATE (days 86–133) gestation has the greatest impact on placental development by reducing uterine and placentome weights. This, in turn, reduced total fetal weight per ewe by 15% in ewes fed E+ seed during LATE gestation (E−/E+ and E+/E+). [ABSTRACT FROM AUTHOR]

Fescue toxicosis is a multifaceted syndrome common in cattle grazing endophyte-infected tall fescue. The objective of this study was to evaluate the impact of the slick hair trait on physiological and reproductive parameters in heifers experiencing fescue toxicosis. Angus × Senepol heifers (n = 31) were blocked by weight (393.5 ± 17.3 kg) and phenotype relative to hair coat at birth, and randomly fed novel endophyte fescue (EN) or endophyte-infected fescue (EI) haylage in a total mixed ration for 91 d. Weekly measurements were collected to monitor heifer growth and response during ergot alkaloids exposure. Following 28 d of treatment, estrus was synchronized and heifers were inseminated. Ovary mapping and AI pregnancy rate were examined via transrectal ultrasonography. Blood samples were taken for genotyping: slick (S) or wildtype (W). Data were analyzed using repeated measures in PROC MIXED of SAS including fescue treatment (EN vs. EI), genotype (S vs. W), and sample collection time as main effects. Body condition scores were decreased for W heifers compared with S heifers (5.48 vs. 5.66, respectively; P < 0.0001). Surface temperature was greater for EI-W heifers (37.2 °C) compared with other groups (36.4, 36.6, 36.7 °C for EN-S, EN-W, EI-S, respectively; P < 0.05). Serum PRL concentrations were reduced for EI heifers compared with EN heifers (133.5 vs. 163.1 ng/mL, respectively; P < 0.05). The average number of 2 to 4 mm follicles were greater in EI-W heifers (13.8 follicles) compared with other groups (12.2, 10.6, and 11.1 for EN-S, EN-W, and EI-S, respectively; P < 0.0001). However, the average number of preovulatory follicles (≥9 mm) were reduced in EI-W heifers (0.52 follicles) compared with other heifer groups (0.94, 0.88, and 0.85 ± 0.04 for EN-S, EN-W, and EI-S, respectively; P < 0.05). Ovulatory follicle size was smaller in EI-W heifers compared with EN-W heifers (9.14 vs. 11.57 mm, respectively; P = 0.05). Corpus luteum area was reduced in EI-W heifers (235.1 mm2) compared with other heifer groups (297.2, 272.7, and 276.8 mm2 for EN-S, EN-W, and EI-S, respectively; P < 0.05). Concentrations of P4 were greater for EN heifers compared with EI heifers (2.7 vs. 1.8 ng/mL, respectively; P < 0.05). Pregnancy was not established in EI-W heifers (0%) compared with other heifer groups (37.5%, 57.1%, and 62.5% for EN-S, EN-W, and EI-S, respectively; P < 0.05). Overall, the slick hair mutation appears to aid in offsetting the physiological symptoms associated with fescue toxicosis and helps to improve reproductive performance. [ABSTRACT FROM AUTHOR]

Medicago sativa L. (alfalfa) is an important forage crop throughout the world. Despite the abiotic nutritional components of alfalfa having been extensively studied, there is only limited information on alfalfa endophytes. In this study, thirteen endophytic bacteria were isolated from alfalfa seeds. Bacillus (76·9%) was the most abundant genus, followed by Enterobacter (15·4%), Brevibacterium (7·7%), Geobacillus (7·7%) and Staphylococcus (7·7%). Four of the 13 endophytic bacteria, including Bacillus amyloliquefaciens EnB‐alf1, Bacillus subtilis EnB‐alf3, EnB‐alf5 and EnB‐alf13, were capable of significantly extending the lifespan of Caenorhabditis elegans. In addition, B. amyloliquefaciens EnB‐alf1 enhanced the resistance of C. elegans to thermal stress whereas B. subtilis EnB‐alf3 enhanced the resistance to oxidative stress. Further studies demonstrated that the enhanced lifespan of the worm was depended on the function of DAF‐2/DAF‐16 and was associated with the colonization of strain in the worms' intestines when strain EnB‐alf1 or strain EnB‐alf3 was presented to the worms as food sources. Our results suggest that some endophytic Bacillus strains isolated from alfalfa are beneficial on C. elegans health. Significance and Impact of the Study: Medicago sativa L. (alfalfa) is an important forage crop throughout the world. Despite the abiotic nutritional components of alfalfa having been extensively studied, there is only limited information available on alfalfa endophytes. Beneficial bacteria residing in the host intestine have been shown to affect host longevity. However, there is limited information available on the functions of alfalfa seed endophytes to nematodes. In this study, four endophytic Bacillus strains isolated from alfalfa seeds were found to significantly extend the lifespan of Caenorhabditis elegans and enhance resistance to thermal and oxidative stress. Our results suggest that some endophytic Bacillus strains isolated from alfalfa seeds can promote good health in C. elegans. Significance and Impact of the Study: Medicago sativa L. (alfalfa) is an important forage crop throughout the world. Despite the abiotic nutritional components of alfalfa having been extensively studied, there is only limited information available on alfalfa endophytes. Beneficial bacteria residing in the host intestine have been shown to affect host longevity. However, there is limited information available on the functions of alfalfa seed endophytes to nematodes. In this study, four endophytic Bacillus strains isolated from alfalfa seeds were found to significantly extend the lifespan of Caenorhabditis elegans and enhance resistance to thermal and oxidative stress. Our results suggest that some endophytic Bacillus strains isolated from alfalfa seeds can promote good health in C. elegans. [ABSTRACT FROM AUTHOR]

Lolium arundinaceum [(Darbyshire) tall fescue] toxicosis is responsible for substantial beef production losses in the United States, due to its negative effects on reproduction, growth, and feed efficiency. These effects are consequences of toxic alkaloids within tall fescue. Interseeding legumes, such as Trifolium pratense (red clover), into pastures has been shown to mitigate a portion of these effects. Clovers contain isoflavones, which may play a role in tall fescue toxicosis mitigation. The present study utilized 36 Angus steers to determine the effects of daily supplementation with a red clover-isolated isoflavone feed additive on physiological symptoms of tall fescue toxicosis and the rumen microbial environment over a 21-d period. Angus steers were initially stratified based upon their single nucleotide polymorphism genotype at the DRD2 receptor. Treatments were then randomly assigned in a 2 × 2 factorial arrangement within a completely randomized design, where treatment factors consisted of tall fescue seed type (endophyte-infected tall fescue seed vs. endophyte-free tall fescue seed) supplemented with and without the isoflavone additive. Steers that consumed endophyte-infected tall fescue seed had lower serum prolactin concentrations (P = 0.0007), average daily gain (ADG; P = 0.003), final body weight (BW; P = 0.004), and feed efficiency (P = 0.018) when compared with steers that consumed endophyte-free tall fescue seed. Serum insulin-like growth factor-1 (IGF-1) tended to be reduced with supplementation of isoflavones (P = 0.06) but was unaffected by seed type (P ≥ 0.10) and seed by treatment interaction (P ≥ 0.10). Isoflavones reduced serum glucose levels (P = 0.023), but neither seed type, isoflavones, or their interaction affected serum urea nitrogen (SUN), nonesterified fatty acids (NEFA), or insulin (P ≥ 0.10). Volatile fatty acid concentrations, dry matter intake (DMI), ruminal pH, and overall feeding behaviors were also unaffected by seed type or isoflavone treatments (P ≥ 0.10). Twenty-eight ruminal bacteria taxa shifted as a result of seed type or isoflavone treatment (P < 0.05). In this experiment, feeding isoflavones to Angus cattle did not completely mitigate all symptoms of fescue toxicosis. However, dose–response trials may aid future research to determine if dietary supplementation with isoflavones alleviates fescue toxicosis symptoms and promotes livestock growth and performance. [ABSTRACT FROM AUTHOR]