Caracterización morfológica y molecular del antagonismo entre el endofito Diaporthe sp. aislado de frailejón (Espeletia sp.) y el fitopatógeno Phytophthora infestans

Endophytic fungi produce a great variety of secondary metabolites both in vivo and in vitro. In this study, we characterized the ability of a sterile-mycelium endophytic fungus isolated from Espeletia sp. to control the growth of Phytophthora infestans in Petri dishes. Sequence from the ITS regions (internal transcribed spacer) of the endophyte showed 94% similarity to Diaporthe phaseolorum's. The antagonistic interaction between Diaporthe sp. and P. infestans was evaluated in three different culture media. Diaporthe sp. showed an antagonistic effect towards P. infestans, with some variation depending on which medium was used. In an attempt to identify possible genes involved in this antagonism, we detected a gene from the endophyte encoding an amylase, which was differentially expressed during this biotic interaction.     

Bionectria ochroleuca NOTL33—an endophytic fungus from Nothapodytes foetida producing antimicrobial and free radical scavenging metabolites

Endophytic fungi are reported to produce diverse classes of secondary metabolites. This study investigated the antimicrobial and free radical scavenging activity of a foliar endophytic fungus from Nothapodytes foetida, a medium sized tree known to produce the antineoplastic compound camptothecin. The fungal isolate was identified as Bionectria ochroleuca based on the ITS rDNA analysis. The differences among endophytic, pathogenic and free living Bionectria ochroleuca were established by RNA secondary structure analysis. The metabolites showed a broad spectrum of antibacterial, antifungal and anti-dermatophytic activity. Minimum inhibitory concentration values of ethyl acetate extracts were in the range of 78–625 μg/mL against all test organisms, except for Pseudomonas aeruginosa (5 mg/mL). Antimicrobial components in the ethyl acetate extract were identified by GC-MS analysis. The isolate was also produced volatile antifungal compounds. A dose-dependent free radical quenching was observed in the ethyl acetate extract. This is the first report on Bionectria sp. as an endophyte of N. foetida. The results indicate that the B. ochroleuca NOTL33 isolate is a potential source of antimicrobial agents and could be used as an effective biofumigant.     

Fungal endophytes from cactus Cereus jamacaru in Brazilian tropical dry forest: a first study

Endophytic fungi live within the healthy tissues of plants and can promote host species tolerance to different environmental stresses. However, most studies have been of plants in humid environments, and there are few reports of the benefits of such associations for plants of extreme environments. Our aims were to identify endophytic fungi using morphological taxonomy, to explore richness and estimate species frequency in a cactus, C. jamacaru, in Brazilian tropical dry forest (Caatinga). We thus identified 59 taxa, corresponding to 69.7 % of the total number of isolates; the other 30.3 % were sterile mycelia. Cladosporium cladosporioides and Fusarium oxysporum were the species most commonly isolated, followed by Acremonium implicatum, Aureobasidium pullulans, Trichoderma viride, Chrysonilia sitophila, and Aspergillus flavus. Forty-seven species are recorded for the first time as endophytic fungi of cacti, and 18 others as endophytes for Brazil; this suggests that C. jamacaru harbors a highly diverse fungal community as measured by a diversity index. However, species accumulation curves suggest that our study still underestimates endophyte diversity because it does not provide an exhaustive sample. To our knowledge, this is the first report of endophytic fungi from C. jamacaru in tropical dry forests.     

Diversity and dynamics of fungal endophytes in leaves, stems and roots of Stellera chamaejasme L. in northwestern China

This study was conducted to explore fungal endophyte communities inhabiting a toxic weed (Stellera chamaejasme L.) from meadows of northwestern China. The effects of plant tissue and growth stage on endophyte assemblages were characterized. Endophytes were recovered from 50 % of the samples, with a total of 714 isolates. 41 operational taxonomical units (OTUs) were identified, consisting of 40 OTUs belonging primarily to Ascomycota and 1 OTU belonging to Basidiomycota. Pleosporales and Hypocreales were the orders contributing the most species to the endophytic assemblages. The total colonization frequency and species richness of endophytic fungi were higher in roots than in leaves and stems. In addition, for the plant tissues, the structure of fungal communities differed significantly by growth stages of leaf emergence and dormancy; for the plant growth stages, the structure of fungal communities differed significantly by plant tissues. This study demonstrates that S. chamaejasme serves as a reservoir for a wide variety of fungal endophytes that can be isolated from various plant tissues.     

Psychrophilic endophytic fungi with biological activity inhabit Cupressaceae plant family

Psychrophilic microorganisms are cold-adapted organisms that have an optimum growth temperature below 15 °C, and often below 5 °C. Endophytic microorganisms live inside healthy plants and biosynthesize an array of secondary metabolites which confer major ecological benefits to their host. We provide information, for the first time, on an endophytic association between bioactive psychrophilic fungi and trees in Cupressaceae plant family living in temperate to cold, semi-arid habitats. We have recovered psychrophilic endophytic fungi (PEF) from healthy foliar tissues of Cupressus arizonica, Cupressus sempervirens and Thuja orientalis (Cupressaceae, Coniferales). In total, 23 such fungi were found out of 110 endophytic fungal isolates. They were identified as ascomycetous fungi, more specifically Phoma herbarum, Phoma sp. and Dothideomycetes spp., all from Dothideomycetes. The optimal growth temperature for all these 23 fungal isolates was 4 °C, and the PEF isolates were able to biosynthesize secondary metabolite at this temperature. Extracted metabolites from PEF showed significant antiproliferative/cytotoxic, antifungal and antibacterial effects against phytopathogenic fungi and bacteria. Of special interest was their antibacterial activity against the ice-nucleation active bacterium Pseudomonas syringae. Accordingly, we suggest that evergreen Cupressaceae plants may benefit from their psychrophilic endophytic fungi during cold stress. Whether such endosymbionts confer any ecological and evolutionary benefits to their host plants remains to be investigated in vivo.     

Neighboring Deschampsia flexuosa and Trientalis europaea harbor contrasting root fungal endophytic communities

Fungal endophytic communities and potential host preference of root-inhabiting fungi of boreal forest understory plants are poorly known. The objective of this study was to find out whether two neighboring plant species, Deschampsia flexuosa (Poaceae) and Trientalis europaea (Primulaceae), share similar root fungal endophytic communities and whether the communities differ between two sites. The study was carried out by analysis of pure culture isolates and root fungal colonization percentages. A total of 84 isolates from D. flexuosa and 27 isolates from T. europaea were obtained. The roots of D. flexuosa harbored 16 different isolate types based on macromorphological characteristics, whereas only 4 isolate types were found in T. europaea. The root colonization by dark septate and hyaline septate hyphae correlated with isolate numbers being higher in D. flexuosa compared to T. europaea. The different isolate types were further identified on the basis of internal transcribed spacer sequence and phylogenetic analysis. An isolate type identified as dark septate endophyte Phialocephala fortinii colonized 50 % of the T. europaea and 21 % of the D. flexuosa specimens. In addition, Meliniomyces variabilis, Phialocephala sphaeroides, and Umbelopsis isabellina were found colonizing the grass, D. flexuosa, for the first time and Mycena sp. was confirmed as an endophyte of D. flexuosa. Site-specific differences were observed in the abundance and diversity of endophytic fungi in the roots of both study plants, but the differences were not as predominant as those between plant species. It is concluded that D. flexuosa harbors both higher amount and more diverse community of endophytic fungi in its roots compared to T. europaea.     

Geographic and Tissue Influences on Endophytic Fungal Communities of Taxus chinensis var. mairei in China

Endophytc fungi were collected from the barks, branches and leaves of Taxus chinensis var. mairei from the Jiangxi, Zhejiang and Chongqing regions of China and their influences on geographic and tissue investigated. A total of 145 fungal taxa were identified based on molecular techniques, of these 125 taxa (86.2 %) belonging to Ascomycota, 14 (9.7 %) to Basidiomycota, 5 (3.4 %) to Zygomycota, and 1 (0.7 %) to undefined fungi. The species richness and diversity of endophytic fungi were significantly affected by tissue, and were 1.2–2.5-fold higher in the branches and barks when compared to the leaves. The locality affected the species richness per tree and the shannon diversity index per tree by longitude. The endophyte assemblages were strongly shaped by locality and tissue according to partial least squares discriminant analysis. In addition, the distributions of dominant fungi at orders and genera levels differed as a function of locality and tissue. Most of the dominant taxa showed spatial heterogeneity and tissue specificity or preference and many fungal taxa with low frequency were special to one locality or one tissue.     

Antifungal Metabolites Produced by Chaetomium globosum No.04, an Endophytic Fungus Isolated from Ginkgo biloba

The fungal endophyte Chaetomium globosum No.04 was isolated from the medicinal plant Ginkgo biloba. The crude extract of the fungus fermentation were active in the agar-diffusion tests against the phytopathogenic fungi Rhizopus stolonifer and Coniothyrium diplodiella. Further bioassay-guided chemical investigation led to the isolation and purification of six alkaloids and three non-targeted compounds from 50 L fermentation of this endophytic fungus and their structures were elucidated as chaetoglobosin A, C, D, E, G, R (1-6), ergosterol, allantoin and uracil, by means of spectroscopic analysis. Compounds 1-6 showed significant growth inhibitory activity against R. stolonifer and C. diplodiella at a concentration of 20 μg/disc. We present here, for the first time, the potent antifungal activity of chaetoglobosins from endophytic fungi against two important phytopathogenic fungi R. stolonifer and C. diplodiella.     

Fungal elicitors stimulate biomass and active ingredients accumulation in <Emphasis Type="Italic">Dendrobium catenatum</Emphasis> plantlets

Endophytic fungi have been widely used as biotic elicitors to stimulate the growth and production of metabolites in plant cells, tissues and organ cultures. Here, mycelium extract (ME), supernatant liquor (SL), ethanol sediment (ES) and protein-polysaccharide fraction (PPF) were prepared from four endophytic fungi, DO14 (Pestalotiopsis sp.), DO18 (Talaromyces sp.), DO19 (Xylariaceae sp.) and DO120 (Hypoxylon sp.), and applied to their host Dendrobium catenatum. After 8 weeks of co-culturing, ME, ES and PPF exhibited strong stimulation on biomass yields and contents of active ingredients. Among the three elicitors, PPF was found to be the active constituent responsible for the enhanced biomass and active ingredients in D. catenatum. Under the treatment of 240 mg/L PPF from DO14, we achieved maximum stem fresh weight (FW) and leaf FW. However, to maximize the productions of polysaccharides, naringenin and schaftoside one need only 60 mg/L of PPF from DO14. PPF from DO18, DO19 and DO120 showed different effects. Under 30 mg/L treatment, the ethanol extractives, total flavonoids and total phenols contents increased most. These results indicate that fungal elicitor PPFs can be used for industrial production of high quality D. catenatum seedlings and may be served as a broad microbial fertilizer resource for other plant growth.     

Utilizing pyrene-degrading endophytic bacteria to reduce the risk of plant pyrene contamination

Aims

Endophytic bacteria are ubiquitous in plants, but little information is available on the influence of endophytic bacteria on the uptake and metabolism of PAH by plants. Thus, we seek to investigate whether the colonization of a target plant by a PAH-degrading endophytic bacterium would improve the PAH metabolism of the plant and reduce the risk of plant PAH contamination.

Methods

A pyrene-degrading endophyte was isolated from PAH-contaminated plants using enrichment culture. After root inoculation with the isolated bacterium, greenhouse container experiments were conducted. Pyrene residues in soil and plant samples were analyzed by HPLC.

Results

A pyrene-degrading endophytic bacterium, Staphylococcus sp. BJ06, was isolated from Alopecurus aequalis and could degrade 56.0 % of pyrene (50 mg?·?L^?1) within 15 days. BJ06 grew and degraded pyrene efficiently under environmental conditions. The bacterium significantly promoted ryegrass growth and pyrene removal from contaminated soil in container experiments. The pyrene concentrations in ryegrass roots and shoots in endophyte-inoculated planted soil were reduced by 31.01 % and 44.22 %, respectively, compared with endophyte-free planted soil.

Conclusions

We have provided new perspectives on the regulation and control of plant uptake of organic contaminants with endophytic bacteria. The results of this study will be valuable to risk assessments of plant PAH contamination.     

Bacterial endophyte Sphingomonas sp. LK11 produces gibberellins and IAA and promotes tomato plant growth

Plant growth promoting endophytic bacteria have been identified as potential growth regulators of crops. Endophytic bacterium, Sphingomonas sp. LK11, was isolated from the leaves of Tephrosia apollinea. The pure culture of Sphingomonas sp. LK11 was subjected to advance chromatographic and spectroscopic techniques to extract and isolate gibberellins (GAs). Deuterated standards of [17, 17-²H₂]-GA₄, [17, 17-²H₂]-GA₉ and [17, 17-²H₂]-GA₂₀ were used to quantify the bacterial GAs. The analysis of the culture broth of Sphingomonas sp. LK11 revealed the existence of physiologically active gibberellins (GA₄: 2.97 ± 0.11 ng/ml) and inactive GA₉ (0.98 ± 0.15 ng/ml) and GA₂₀ (2.41 ± 0.23). The endophyte also produced indole acetic acid (11.23 ± 0.93 μM/ml). Tomato plants inoculated with endophytic Sphingomonas sp. LK11 showed significantly increased growth attributes (shoot length, chlorophyll contents, shoot, and root dry weights) compared to the control. This indicated that such phyto-hormones-producing strains could help in increasing crop growth.     

Endophyte communities vary in the needles of Norway spruce clones

Endophytic fungi show no symptoms of their presence but can influence the performance and vitality of host trees. The potential use of endophytes to indicate vitality has been previously realized, but a standard protocol has yet to be developed due to an incomplete understanding of the factors that regulate endophyte communities. Using a culture-free molecular approach, we examined the extent to which host genotype influences the abundance, species richness, and community composition of endophytic fungi in Norway spruce needles. Briefly, total DNA was extracted from the surface-sterilized needles of 30 clones grown in a nursery field and the copy number of the fungal internal transcribed spacer (ITS) region of ribosomal DNA was estimated by quantitative PCR. Fungal species richness and community composition were determined by denaturing gradient gel electrophoresis and DNA sequencing. We found that community structure and ITS copy number varied among spruce clones, whereas species richness did not. Host traits interacting with endophyte communities included needle surface area and the location of cuttings in the experimental area. Although Lophodermium piceae is considered the dominant needle endophyte of Norway spruce, we detected this species in only 33 % of samples. The most frequently observed fungus (66 %) was the potentially pathogenic Phoma herbarum. Interestingly, ITS copy number of endophytic fungi correlated negatively with the richness of ectomycorrhizal fungi and thus potential interactions between fungal communities and their influence on the host tree are discussed. Our results suggest that in addition to environmental factors, endophyte communities of spruce needles are determined by host tree identity and needle surface area.     

A Legume Genetic Framework Controls Infection of Nodules by Symbiotic and Endophytic Bacteria

Legumes have an intrinsic capacity to accommodate both symbiotic and endophytic bacteria within root nodules. For the symbionts, a complex genetic mechanism that allows mutual recognition and plant infection has emerged from genetic studies under axenic conditions. In contrast, little is known about the mechanisms controlling the endophytic infection. Here we investigate the contribution of both the host and the symbiotic microbe to endophyte infection and development of mixed colonised nodules in Lotus japonicus. We found that infection threads initiated by Mesorhizobium loti, the natural symbiont of Lotus, can selectively guide endophytic bacteria towards nodule primordia, where competent strains multiply and colonise the nodule together with the nitrogen-fixing symbiotic partner. Further co-inoculation studies with the competent coloniser, Rhizobium mesosinicum strain KAW12, show that endophytic nodule infection depends on functional and efficient M. loti-driven Nod factor signalling. KAW12 exopolysaccharide (EPS) enabled endophyte nodule infection whilst compatible M. loti EPS restricted it. Analysis of plant mutants that control different stages of the symbiotic infection showed that both symbiont and endophyte accommodation within nodules is under host genetic control. This demonstrates that when legume plants are exposed to complex communities they selectively regulate access and accommodation of bacteria occupying this specialized environmental niche, the root nodule.     

Endophytic Bacteria Improve Seedling Growth of Sunflower Under Water Stress, Produce Salicylic Acid, and Inhibit Growth of Pathogenic Fungi

Endophytic bacterial strains SF2 (99.9% homology with Achromobacter xylosoxidans), and SF3 and SF4 (99.9% homology with Bacillus pumilus) isolated from sunflower grown under irrigation or drought were selected on the basis of plant growth-promoting bacteria (PGPB) characteristics. Aims of the study were to examine effects of inoculation with SF2, SF3, and SF4 on sunflower cultivated under water stress, to evaluate salicylic acid (SA) production by these strains in control medium or at Ψa = ?2.03 MPa, and to analyze effects of exogenously applied SA, jasmonic acid (JA), bacterial pellets, and bacterial supernatants on growth of pathogenic fungi Alternaria sp., Sclerotinia sp., and Verticillum sp. Growth response to bacterial inoculation was studied in two inbred lines (water stress-sensitive B59 and water stress-tolerant B71) and commercial hybrid Paraiso 24. Under both water stress and normal conditions, plant growth following inoculation was more strongly enhanced for Paraiso 24 and B71 than for B59. All three strains produced SA in control medium; levels for SF3 and SF4 were higher than for SF2. SA production was dramatically higher at Ψa = ?2.03 MPa. Exogenously applied SA or JA caused a significant reduction of growth for Sclerotinia and a lesser reduction for Alternaria and Verticillum. Fungal growth was more strongly inhibited by bacterial pellets than by bacterial supernatants. Our findings indicate that these endophytic bacteria enhance growth of sunflower seedlings under water stress, produce SA, and inhibit growth of pathogenic fungi. These characteristics are useful for formulation of inoculants to improve growth and yield of sunflower crops.     

ENHANCEMENT OF RUTIN PRODUCTION IN Fagopyrum tataricum HAIRY ROOT CULTURES WITH ITS ENDOPHYTIC FUNGAL ELICITORS

Tartary buckwheat (Fagopyrum tataricum) is a potentially important source of rutin, a natural bioactive flavonoid with antihyperglycemic, antioxidative, antihypertensive, and anti-inflammatory properties. This study examines the effects of endophytic fungi on rutin production in the hairy root cultures of F. tataricum. Without obvious changes in the appearance of the hairy roots, the exogenous fungal mycelia elicitors efficiently stimulated the hairy root growth and rutin biosynthesis, and the stimulation effect was mainly dependent on the mycelia elicitor species, as well as its treatment dose. Two endophytic fungal isolates Fat9 (Fusarium oxysporum) and Fat15 (Alternaria sp.) were screened as promising candidates for promoting F. tataricum hairy root growth and rutin production. With application of polysaccharide (PS) of endophyte Fat9 (200 mg/L), and PS of endophyte Fat15 (100 mg/L) to the hairy root cultures on day 25, the rutin yield was increased to 45.9 mg/L and 47.2 mg/L, respectively. That was about 3.1- to 3.2-fold in comparison with the control level of 14.6 mg/L. Moreover, the present study revealed that the accumulation of rutin resulted from the stimulation of the phenylpropanoid pathway by mycelia PS treatments. This may be an efficient strategy for enhancing rutin production in F. tataricum hairy root culture provided with its endophytic mycelia elicitors.     

Endophytic hyphal compartmentalization is required for successful symbiotic Ascomycota association with root cells

Root endophytic fungi are seen as promising alternatives to replace chemical fertilizers and pesticides in sustainable and organic agriculture systems. Fungal endophytes structure formations play key roles in symbiotic intracellular association with plant-roots. To compare the morphologies of Ascomycete endophytic fungi in wheat, we analyzed growth morphologies during endophytic development of hyphae within the cortex of living vs. dead root cells. Confocal laser scanning microscopy (CLSM) was used to characterize fungal cell morphology within lactofuchsin-stained roots. Cell form regularity Ireg and cell growth direction Idir, indexes were used to quantify changes in fungal morphology. Endophyte fungi in living roots had a variable Ireg and Idir values, low colonization abundance and patchy colonization patterns, whereas the same endophyte species in dead (γ-irradiated) roots had consistent form of cells and mostly grew parallel to the root axis. Knot, coil and vesicle structures dominated in living roots, as putative symbiotic functional organs. Finally, an increased hypha septation in living roots might indicate local specialization within endophytic Ascomycota. Our results suggested that the applied method could be expanded to other septate fungal symbionts (e.g. Basidiomycota). The latter is discussed in light of our results and other recent discoveries.     

Efficient strategy for maintaining and enhancing the huperzine A production of Shiraia sp. Slf14 through inducer elicitation

Huperzine A (HupA), a naturally occurring lycopodium alkaloid, is a potent, highly specific and reversible inhibitor of acetylcholinesterase and is a potential treatment for Alzheimer’s disease. However, isolating HupA from Huperziaceae plants is inefficient; thus, extracting this compound from endophytic fungi may be more controllable and sustainable. However, the large-scale production of this chemical from endophytes is limited by the innate instability of endophytic fungi. In this study, we maintained the stability and viability of the HupA-producing endophytic fungus Shiraia sp. Slf14 and enhanced the HupA titers during fermentation by adding Huperzia serrata extracts (HSE), l-lysine, and acetic acid into the culture as inducers. Adding trace amounts of HupA clearly improved the HupA production of Shiraia sp. Slf14, reaching a maximum content of approximately 40 μg g^?1. Moreover, the addition of HSE and l-lysine promoted HupA production in the flask fermentation. The aforementioned bioprocessing strategy may be potentially applied to other endophytic fungal culture systems for the efficient production of plant secondary metabolites.     

Phylogeny,antimicrobial, antioxidant and enzyme-producing potential of fungal endophytes found in <Emphasis Type="Italic">Viola odorata</Emphasis>

Viola odorata, a medicinal plant, is traditionally used to treat common cold, congestion and cough. Given its medicinal properties and occurrence in the northwestern Himalayas, we isolated and characterized endophytic fungi from this plant morphologically, microscopically and by internal transcribed spacer-based rDNA sequencing. In total, we isolated 27 morphotypes of endophytes belonging to phyla Ascomycota and Basidiomycota. The roots showed the highest diversity of endophyte as well as fungal dominance, followed by leaves and leaf nodes. The fungal extract of VOR16 (Fusarium oxysporum) displayed potent antimicrobial activity against Salmonella typhimurium, Klebsiella pneumoniae and Escherichia coli, with a minimum inhibitory concentration of 0.78, 0.78 and 1.56 μg/mL, respectively, while fungal extract VOLF4 (Aspergillus sp.) exhibited promising antioxidant activity (IC₅₀ of 17.4 μg/mL). To identify the components responsible for various bioactivities, we analyzed the content of penicillin G in the extract of bioactive endophytes. The results suggested that the expression of penicillin G under the fermentation conditions applied was too low to display antimicrobial effects. Thus, the activity may be contributed by a different, novel secondary metabolite. The antioxidant activity of VOLF4 may be attributed to its high content of flavonoids. Of the endophytic fungi assessed, 27% were found to be enzyme producers. The highest zone of clearance was observed in VOLN5 (Colletotrichum siamense) for protease production. Only VOR5 (Fusarium nematophilum) was found to be a producer of cellulase, glutenase, amylase and protease. In summary, this is the first report of the isolation of endophytes, namely Fusarium nematophilum, Colletotrichum trifolii, C. destructivum, C. siamense and Peniophora sp., from V. odorata and their bioactive and enzyme-producing potential.     

Fungal endophytes of turmeric (<Emphasis Type="Italic">Curcuma longa</Emphasis> L.) and their biocontrol potential against pathogens <Emphasis Type="Italic">Pythium aphanidermatum</Emphasis> and <Emphasis Type="Italic">Rhizoctonia solani</Emphasis>

Endophytic fungi have been isolated from the healthy turmeric (Curcuma longa L.) rhizomes from South India. Thirty-one endophytes were identified based on morphological and ITS–rDNA sequence analysis. The isolated endophytes were screened for antagonistic activity against Pythium aphanidermatum (Edson) Fitzp., and Rhizoctonia solani Kuhn., causing rhizome rot and leaf blight diseases in turmeric respectively. Results revealed that only six endophytes showed >?70% suppression of test pathogens in antagonistic dual culture assays. The endophyte T. harzianum TharDOB-31 showed significant in vitro mycelial growth inhibition of P. aphanidermatum (76.0%) and R. solani (76.9%) when tested by dual culture method. The SEM studies of interaction zone showed morphological abnormalities like parasitism, shriveling, breakage and lysis of hyphae of the pathogens by endophyte TharDOB-31. Selected endophytic isolates recorded multiple plant growth promoting traits in in vitro studies. The rhizome bacterization followed by soil application of endophyte TharDOB-31 showed lowest Percent Disease Incidence of rhizome rot and leaf blight, 13.8 and 11.6% respectively. The treatment of TharDOB-31 exhibited significant increase in plant height (85 cm) and fresh rhizome yield/plant (425 g) in comparison with untreated control under greenhouse condition. The confocal microscopy validates the colonization of the TharDOB-31 in turmeric rhizomes. The secondary metabolites in ethyl acetate extract of TharDOB-31 were found to contain higher number of antifungal compounds by high resolution liquid chromatograph mass spectrometer analysis. Thereby, endophyte T. harzianum isolate can be exploited as a potential biocontrol agent for suppressing rhizome rot and leaf blight diseases in turmeric.     

Diversity and decomposition potential of endophytes in leaves of a Cinnamomum camphora plantation in China

This study was carried out to improve our understanding of the diversity and decomposition potential of endophytes in the leaves of Cinnamomum camphora trees grown in a subtropical region of China. We isolated and identified endophytic fungi from senescent leaves of C. camphora and tested their role in decomposition through pure-culture and pre-colonization. A total of 2,861 endophytic fungi isolated from 69 leaves of C. camphora were grouped into 39 taxa comprising 36 Ascomycetes and 3 Basidiomycetes based on sporulation and ITS sequence analysis. Of these, Colletotrichum gloeosporioides was the most common species (69% relative abundance and 96% colonization frequency), followed by Cladosporium sp.1, Colletotrichum sp. and Chaetomium sp. All 39 endophytes had the ability to decompose C. camphora leaf litter in pure culture, and a few exhibited >20% litter mass loss in 2 months. In most cases, single endopyhytic species showed lower mass loss than mixed microbial groups from active soil after 60 or 120 days. In pre-inoculation, endophytic fungi like Chaetomium sp., Cladosporium sp.1, C. gloeosporioides, Colletotrichum sp. and Guignardia sp. exhibited higher abundance and caused greater mass loss, indicating the potential of these groups to enter and significantly accelerate the process of decomposition. This study concludes that, after entering the decomposition process, selected endophytic fungi with high abundance could influence significantly the decomposition process and thus probably affect carbon and nutrient cycling in C. camphora plantations.