Beneficial Fungi Research Articles

Insight into the Microbiological Control Strategies against Botrytis cinerea Using Systemic Plant Resistance Activation

Botrytis cinerea is a polyphagous necrotrophic fungus and is the causal agent of grey mold diseases in more than 1400 different hosts. This fungus causes serious economic losses in both preharvest and post-harvest—mainly in grape, strawberry, and tomato crops—and is the second most important pathogen worldwide, to our knowledge. Beneficial bacteria and fungi are efficient biocontrol agents against B. cinerea through direct mechanisms, such as parasitism, antibiosis, and competition, but also indirectly through the activation of systemic plant resistance. The interaction between plants and these microorganisms can lead to the development of defensive responses in distant plant organs, which are highly effective against foliar, flower, and fruit pathogens, such as B. cinerea. This review aimed to explore the systemic plant defense responses against B. cinerea by compiling all cases reported (to the best of our knowledge) on the use of beneficial bacteria and fungi for agriculture, a subject not yet specifically addressed.

Cork Oak Endophytic Fungi as Potential Biocontrol Agents against Biscogniauxia mediterranea and Diplodia corticola.

An increase in cork oak diseases caused by Biscogniauxia mediterranea and Diplodia corticola has been reported in the last decade. Due to the high socio-economic and ecologic importance of this plant species in the Mediterranean Basin, the search for preventive or treatment measures to control these diseases is an urgent need. Fungal endophytes were recovered from cork oak trees with different disease severity levels, using culture-dependent methods. The results showed a higher number of potential pathogens than beneficial fungi such as cork oak endophytes, even in healthy plants. The antagonist potential of a selection of eight cork oak fungal endophytes was tested against B. mediterranea and D. corticola by dual-plate assays. The tested endophytes were more efficient in inhibiting D. corticola than B. mediterranea growth, but Simplicillium aogashimaense, Fimetariella rabenhorstii, Chaetomium sp. and Alternaria alternata revealed a high potential to inhibit the growth of both. Simplicillium aogashimaense caused macroscopic and microscopic mycelial/hyphal deformations and presented promising results in controlling both phytopathogens’ growth in vitro. The evaluation of the antagonistic potential of non-volatile and volatile compounds also revealed that A. alternata compounds could be further explored for inhibiting both pathogens. These findings provide valuable knowledge that can be further explored in in vivo assays to find a suitable biocontrol agent for these cork oak diseases.

Plant Cell Wall Changes in Common Wheat Roots as a Result of Their Interaction with Beneficial Fungi of Trichoderma.

Plant cell walls play an important role in shaping the defense strategies of plants. This research demonstrates the influence of two differentiators: the lifestyle and properties of the Trichoderma species on cell wall changes in common wheat seedlings. The methodologies used in this investigation include microscopy observations and immunodetection. In this study was shown that the plant cell wall was altered due to its interaction with Trichoderma. The accumulation of lignins and reorganization of pectin were observed. The immunocytochemistry indicated that low methyl-esterified pectins appeared in intercellular spaces. Moreover, it was found that the arabinogalactan protein epitope JIM14 can play a role in the interaction of wheat roots with both the tested Trichoderma strains. Nevertheless, we postulate that modifications, such as the appearance of lignins, rearrangement of low methyl-esterified pectins, and arabinogalactan proteins due to the interaction with Trichoderma show that tested strains can be potentially used in wheat seedlings protection to pathogens.

Plant growth promotion and suppression of bacterial wilt incidence in tomato by rhizobacteria, bacterial endophytes and the root endophytic fungus Piriformospora indica

Four strains each of rhizobacteria and endophytic bacteria, and the root colonizing beneficial fungus Piriformospora indica were assessed for their biological control potential against tomato bacterial wilt disease caused by Ralstonia solanacearum. Two endophytic bacterial isolates, Bacillus velezensis PCSE10 and Streptomyces leeuwenhoekii KBT004 and one rhizobacterium Bacillus amyloliquefaciens VLY24 showed direct in vitro antagonism against the pathogen. Culture filtrate of B. velezensis PCSE10, B. amyloliquefaciens VLY24 and P. indica inhibited the growth of the pathogen. Among the eight bacterial strains, only Rhizobium radiobacter PCRE10 and S. leeuwenhoekii KBT004 were found to be compatible with P. indica in dual culture plate assay. Two varieties of tomato, Naveen (highly wilt susceptible hybrid) and Vellayani Vijay (moderately wilt tolerant selection) were used to evaluate the biocontrol efficacy of the bacterial bioagents and the fungal endophyte, both individually and in combinations. Disease incidence in Naveen after 21 days of pathogen inoculation was the minimum (15%) when seeds were treated with R. radiobacter PCRE10. In Vellayani Vijay, seed treatment with S. leeuwenhoekii KBT004 was the best individual treatment with a disease incidence of 30%. Treatment with P. indica showed similar results in both the varieties with 40% disease suppression. This is the first report of involvement of P. indica in suppression of a bacterial plant pathogen. Combined inoculation of P. indica with selected compatible bacterial agents did not show any promising results. However, in the nursery, seed treatment with all the bioagents showed improved seedling growth when compared with untreated control.

Keystone metabolites of crop rhizosphere microbiomes

The role of microbes in sustaining agricultural plant growth has great potential consequences for human prosperity. Yet we have an incomplete understanding of the basic function of rhizosphere microbial communities and how they may change under future stresses, let alone how these processes might be harnessed to sustain or improve crop yields. A reductionist approach may aid the generation and testing of hypotheses that can ultimately be translated to agricultural practices. With this in mind, we ask whether some rhizosphere microbial communities might be governed by 'keystone metabolites', envisioned here as microbially produced molecules that, through antibiotic and/or growth-promoting properties, may play an outsized role in shaping the development of the community spatiotemporally. To illustrate this point, we use the example of redox-active metabolites, and in particular phenazines, which are produced by many bacteria found in agricultural soils and have well-understood catalytic properties. Phenazines can act as potent antibiotics against a variety of cell types, yet they also can promote the acquisition of essential inorganic nutrients. In this essay, we suggest the ways these metabolites might affect microbial communities and ultimately agricultural productivity in two specific scenarios: firstly, in the biocontrol of beneficial and pathogenic fungi in increasingly arid crop soils and, secondly, through promotion of phosphorus bioavailability and sustainable fertilizer use. We conclude with specific proposals for future research.

Crop rotation alleviates replant failure in Panax notoginseng (Burkill) F.H. Chen by changing the composition but not the structure of the microbial community

Consecutive monocropping with sanqi (Panax notoginseng (Burkill) F. H. Chen) can increase the abundances of pathogens in soil, resulting in soil sickness. Crop rotation is one way to alleviate this problem. In the present study, there were no differences in microbial structure or bacterial alpha diversity among one-year monocropping soil, one-year rotation soil, and ten-year rotation soil. However, monocropping practices decreased fungal alpha diversity. The relative abundance of copiotrophic bacteria decreased after sanqi monocropping, while that of oligotrophic bacteria increased. Ten-year rotation significantly increased the abundance of potential beneficial bacterial genera. Moreover, the potential beneficial fungal genera were also enriched by rotation for ten years. Furthermore, the relative abundance of Cylindrocarpon spp. decreased dramatically after a ten-year rotation. The results of pot experiments showed that disease incidences after ten-year rotation were significantly decreased among the three treatments. Hence, we suggested that pausing sanqi cultivation for a long time can increase the abundance of potentially beneficial soil bacteria and fungi that are helpful for overcoming soil sickness in sanqi cultivation.

A 2-kb Mycovirus Converts a Pathogenic Fungus into a Beneficial Endophyte for Brassica Protection and Yield Enhancement

Mycoviruses are viruses that infect fungi, and hypovirulence-associated mycoviruses have the potential to control fungal diseases. However, it is unclear how mycovirus-mediated hypovirulent strains live and survive in the field, and no mycovirus has been applied for field crop protection. In this study, we found that a previously identified small DNA mycovirus (SsHADV-1) can convert its host, Sclerotinia sclerotiorum, from a typical necrotrophic pathogen to a beneficial endophytic fungus. SsHADV-1 downregulates the expression of key pathogenicity factor genes in S. sclerotiorum during infection. When growing in rapeseed, the SsHADV-1-infected strain DT-8 significantly regulates the expression of rapeseed genes involved in defense, hormone signaling, and circadian rhythm pathways. As a result, plant growth is promoted and disease resistance is enhanced. Field experiments showed that spraying DT-8 at the early flowering stage can reduce the disease severity of rapeseed stem rot by 67.6% and improve yield by 14.9%. Moreover, we discovered that SsHADV-1 could also infect other S. sclerotiorum strains on DT-8-inoculated plants and that DT-8 could be recovered from dead plants. These findings suggest that the mycoviruses may have the ability to shape the origin of endophytism. Our discoveries suggest that mycoviruses may influence the origin of endophytism and may also offer a novel strategy for disease control in which mycovirus-infected strains are used to improve crop health and release mycoviruses into the field.

Mycosynthesis of ZnO Nanoparticles Using Trichoderma spp. Isolated from Rhizosphere Soils and Its Synergistic Antibacterial Effect against Xanthomonas oryzae pv. oryzae.

The Plant Growth Promoting Fungi (PGPF) is used as a source of biofertilizers due to their production of secondary metabolites and beneficial effects on plants. The present work is focused on the co-cultivation of Trichoderma spp. (T. harzianum (PGT4), T. reesei (PGT5) and T. reesei (PGT13)) and the production of secondary metabolites from mono and co-culture and mycosynthesis of zinc oxide nanoparticles (ZnO NPs), which were characterized by a UV visible spectrophotometer, Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDAX) and Transmission Electron Microscope (TEM) and Selected Area (Electron) Diffraction (SAED) patterns. The fungal secondary metabolite crude was extracted from the mono and co-culture of Trichoderma spp. And were analyzed by GC-MS, which was further subjected for antibacterial activity against Xanthomonas oryzae pv. Oryzae, the causative organism for Bacterial Leaf Blight (BLB) in rice. Our results showed that the maximum zone of inhibition was recorded from the co-culture of Trichoderma spp. rather than mono cultures, which indicates that co-cultivation of beneficial fungi can stimulate the synthesis of novel secondary metabolites better than in monocultures. ZnO NPs were synthesized from fungal secondary metabolites of mono cultures of Trichoderma harzianum (PGT4), Trichoderma reesei (PGT5), Trichoderma reesei (PGT13) and co-culture (PGT4 + PGT5 + PGT13). These ZnO NPs were checked for antibacterial activity against Xoo, which was found to be of a dose-dependent manner. In summary, the biosynthesized ZnO NPs and secondary metabolites from co-culture of Trichoderma spp. are ecofriendly and can be used as an alternative for chemical fertilizers in agriculture.

Alleviating soil degradation caused by watermelon continuous cropping obstacle: Application of urban waste compost

Soil degradation caused by watermelon continuous cropping obstacle is a serious problem in China. Compost, as a soil conditioner, has great potential in improving soil degradation. In order to explore how compost affects the soil quality under continuous cropping obstacle, associations among soil chemical characteristics, microbial community structures and agronomic variables were analyzed and compared. Results showed that soil pH, available potassium, alkali-hydrolyzable nitrogen and organic matter changed significantly after using maize straw compost and sludge compost, which indicated the feasibility of composts as soil remediations. This is also reflected on the significant changes of soil microbial community. Mizugakiibacter, as the main reason of watermelon continuous cropping obstacle, decreased significantly after using compost products. It also showed a negative connection with most chemical characteristics. Rhodanobacter and Galbibacter increased significantly after using compost products, which were positively related to most chemical characteristics. The increase of them was helpful to reduce Mizugakiibacter. Beneficial bacteria were positively related to beneficial fungi (Chaetomium and Chrysosporium). The increase of them and the decrease of Verticillium also helped to improve microbial community structure. The results indicated that compost as a useful and inexpensive technique could alleviate soil degradation caused by watermelon continuous cropping obstacle.

An improved strategy to analyse strigolactones in complex sample matrices using UHPLC\u2013MS/MS

BackgroundStrigolactones represent the most recently described group of plant hormones involved in many aspects of plant growth regulation. Simultaneously, root exuded strigolactones mediate rhizosphere signaling towards beneficial arbuscular mycorrhizal fungi, but also attract parasitic plants. The seed germination of parasitic plants induced by host strigolactones leads to serious agricultural problems worldwide. More insight in these signaling molecules is hampered by their extremely low concentrations in complex soil and plant tissue matrices, as well as their instability. So far, the combination of tailored isolation—that would replace current unspecific, time-consuming and labour-intensive processing of large samples—and a highly sensitive method for the simultaneous profiling of a broad spectrum of strigolactones has not been reported.ResultsDepending on the sample matrix, two different strategies for the rapid extraction of the seven structurally similar strigolactones and highly efficient single-step pre-concentration on polymeric RP SPE sorbent were developed and validated. Compared to conventional methods, controlled temperature during the extraction and the addition of an organic modifier (acetonitrile, acetone) to the extraction solvent helped to tailor strigolactone isolation from low initial amounts of root tissue (150 mg fresh weight, FW) and root exudate (20 ml), which improved both strigolactone stability and sample purity. We have designed an efficient UHPLC separation with sensitive MS/MS detection for simultaneous analysis of seven natural strigolactones including their biosynthetic precursors—carlactone and carlactonoic acid. In combination with the optimized UHPLC–MS/MS method, attomolar detection limits were achieved. The new method allowed successful profiling of seven strigolactones in small exudate and root tissue samples of four different agriculturally important plant species—sorghum, rice, pea and tomato.ConclusionThe established method provides efficient strigolactone extraction with aqueous mixtures of less nucleophilic organic solvents from small root tissue and root exudate samples, in combination with rapid single-step pre-concentration. This method improves strigolactone stability and eliminates the co-extraction and signal of matrix-associated contaminants during the final UHPLC–MS/MS analysis with an electrospray interface, which dramatically increases the overall sensitivity of the analysis. We show that the method can be applied to a variety of plant species.

Community Structure of Arbuscular Mycorrhizal Fungi in Soils of Switchgrass Harvested for Bioenergy.

Learning more about the biodiversity and composition of arbuscular mycorrhizal fungi (AMF) under alternative agricultural management scenarios may be important to the sustainable intensification of switchgrass grown as a bioenergy crop. Using PacBio single-molecule sequencing and taxonomic resolution to the level of amplicon sequence variant (ASV), we assessed the effects of nitrogen amendment on AMF associating with switchgrass and explored relationships between AMF and switchgrass yield across three sites of various productivities in Wisconsin. Nitrogen amendment had little effect on AMF diversity metrics or community composition. While AMF ASV diversity was not correlated with switchgrass yield, AMF family richness and switchgrass yield had a strong, positive relationship at one of our three sites. Each of our sites was dominated by unique ASVs of the species Paraglomus brasilianum, indicating regional segregation of AMF at the intraspecific level. Our molecular biodiversity survey identified putative core members of the switchgrass microbiome, as well as novel clades of AMF, especially in the order Paraglomerales and the genus Nanoglomus Furthermore, our phylogenies unite the cosmopolitan, soil-inhabiting clade deemed GS24 with Pervetustaceae, an enigmatic family prevalent in stressful environments. Future studies should isolate and characterize the novel genetic diversity found in switchgrass agroecosystems and explore the potential yield benefits of AMF richness.IMPORTANCE We assessed the different species of beneficial fungi living in agricultural fields of switchgrass, a large grass grown for biofuels, using high-resolution DNA sequencing. Contrary to our expectations, the fungi were not greatly affected by fertilization. However, we found a positive relationship between plant productivity and the number of families of beneficial fungi at one site. Furthermore, we sequenced many species that could not be identified with existing reference databases. One group of fungi was highlighted in an earlier study for being widely distributed but of unknown taxonomy. We discovered that this group belonged to a family called Pervetustaceae, which may benefit switchgrass in stressful environments. To produce higher-yielding switchgrass in a more sustainable manner, it could help to study these undescribed fungi and the ways in which they may contribute to greater switchgrass yield in the absence of fertilization.

Citrate-silver nanoparticles and their impact on some environmental beneficial fungi.

Colloidal suspensions of silver nanoparticles (AgNPs) with surface modified by capping with citrate ions were synthesized by chemical reduction method. Transmission and Scanning Electron Microscopy as well as darkfield Optical Microscopy provided information on the nanoparticle morphology, with fine symmetrical grains and log-normal fitted size distribution. Small Angle X-ray Scattering method allowed theoretical confirmation of colloidal silver nanoparticle fine granularity, based on measurements in the native fluid sample. UV–Vis spectrophotometry allowed studying the Localized Surface Plasmon Resonance band versus the stability of the citrate-AgNP sample after storage and after UV-C exposure. The colloidal AgNP impact on Phanerochaete chrysosporium environmental microorganisms was studied by specific biochemical investigations. Silver released from the colloidal suspension of AgNPs was supposed to induce changes in some antioxidant enzymes and in some enzymes of Krebs’ cycle. Catalase activity was moderately changed (an increase with over 50%) as well as superoxide dismutase activity, while the diminution of the activities of four dehydrogenases synthesized in the fungus mycelium was emphasized also: a decrease with about 60% for malate dehydrogenase, with over 50% for isocitrate dehydrogenase and succinate dehydrogenase and with about 40% for alpha-ketoglutarate dehydrogenase. These findings suggested the nano-toxicological issues of citrate-AgNPs impact on the environmental beneficial microorganisms.

Seasonal Variation in the Rhizosphere and Non-Rhizosphere Microbial Community Structures and Functions of Camellia yuhsienensis Hu.

Camellia yuhsienensis Hu, endemic to China, is a predominant oilseed crop, due to its high yield and pathogen resistance. Past studies have focused on the aboveground parts of C. yuhsienensis, whereas the microbial community of the rhizosphere has not been reported yet. This study is the first time to explore the influence of seasonal variation on the microbial community in the rhizosphere of C. yuhsienensis using high-throughput sequencing. The results showed that the dominant bacteria in the rhizosphere of C. yuhsienensis were Chloroflexi, Proteobacteria, Acidobacteria, Actinobacteria, and Planctomycetes, and the dominant fungi were Ascomycota, Basidiomycota, and Mucoromycota. Seasonal variation has significant effects on the abundance of the bacterial and fungal groups in the rhizosphere. A significant increase in bacterial abundance and diversity in the rhizosphere reflected the root activity of C. yuhsienensis in winter. Over the entire year, there were weak correlations between microorganisms and soil physiochemical properties in the rhizosphere. In this study, we found that the bacterial biomarkers in the rhizosphere were chemoorganotrophic Gram-negative bacteria that grow under aerobic conditions, and fungal biomarkers, such as Trichoderma, Mortierella, and Lecanicillium, exhibited protection against pathogens in the rhizosphere. In the rhizosphere of C. yuhsienensis, the dominant functions of the bacteria included nitrogen metabolism, oxidative phosphorylation, glycine, serine and threonine metabolism, glutathione metabolism, and sulfur metabolism. The dominant fungal functional groups were endophytes and ectomycorrhizal fungi of a symbiotroph trophic type. In conclusion, seasonal variation had a remarkable influence on the microbial communities and functions, which were also significantly different in the rhizosphere and non-rhizosphere of C. yuhsienensis. The rhizosphere of C. yuhsienensis provides suitable conditions with good air permeability that allows beneficial bacteria and fungi to dominate the soil microbial community, which can improve the growth and pathogen resistance of C. yuhsienensis.

Trichoderma spp. and a carob (Ceratonia siliqua) galactomannan to control the root-knot nematode Meloidogyne incognita on tomato plants

Restrictions about the use of chemicals have limited the availability of control measures against plant-parasitic nematodes. The search for more sustainable approaches has focused the attention on biological control agents, such as Trichoderma species. In recent years, there has been a growing interest in the use of biopolymers for a wide range of applications. These polysaccharide-based compounds may be 20 good carriers of microbial agents or act as barriers against pathogens or pests for their ability to form coating films. In this study, we evaluated the combination of a biopolymer obtained from the leguminous plant Ceratonia siliqua and T. harzianum M10, T. atroviride P1 or T. longibrachiatum MK1, as root protector or adjuvant agents, for the management of the root-knot nematode Meloidogyne incognita. Coating tomato roots with the carob galactomannan biopolymer followed by soil application of selected Trichoderma strains reduced the root galling index caused by M. incognita and soil nematode population in comparison to untreated control under greenhouse conditions. 25 Scanning electron microscopy revealed that coated tomato roots were embedded within a polymeric material. The sedimentation test showed that the addition of this biopolymer retarded the tendency of Trichoderma spores to settle in the bottom of aqueous suspension. In conclusion, beneficial fungi combined or formulated with a biopolymer could represent a promising strategy to increase their activity in plant protection and enhance their proliferation or distribution into rhizosphere.

Isolation and identification of beneficial orchid mycorrhizal fungi in Bletilla striata (Thunb.) Rchb.f.(Orchidaceae)

ABSTRACT Orchid mycorrhizal fungi (OMF) are essential for orchids growth. Bletilla striata (Thunb.) Rchb.f.(Orchidaceae) has high ornamental and medicinal value. Beneficial OMF isolation is crucial to improve the survival rate of B. striata tissue culture and transplanting. In this study, we isolated and identified the beneficial OMF in B. striata from the roots of sterilized wild B. striata seedlings by culturing in four different mediums. The germination states of B. striata seeds inoculated with diverse OMF were classified and calculated. Fresh and dry weight increments of B. striata seedlings inoculated with diverse OMF were recorded after 90 d of culturing on 1/2 MS medium. ITS sequences of beneficial fungi were amplified by PCR and taxonomically identified using BLAST against the GenBank nucleotide database. Ten kinds of OMF strains were isolated from B. striata and named R1 to R10. R6 significantly promoted B. striata seeds germination (p < .01). R3 and R6 significantly promoted both the fresh and dry weight increments of B. striata seedlings (p < .05). The ITS sequence of R6 was most similar to the sequence of Serendipita. R3 was identified as Schizothecium fimbriatum by 100% ITS identity. R6 and R3 were beneficial OMF in B. striata.

Trichoderma virens Alt a 1 protein may target maize PR5/thaumatin-like protein to suppress plant defence: An in silico analysis

Trichoderma spp. are plant beneficial fungi that colonize roots, but unlike plant pathogens, impart defence. Recently, however, some small secreted cysteine-rich proteins have been identified in Trichoderma secretome, deletion of which improves induced defence. The mechanism of such “unusual” behaviour of a plant-beneficial fungus is not understood. In the present study, through in silico analysis, we attempted to explore if such proteins indeed suppress defence by interacting with plant proteins, much like pathogens, taking Alt a 1 protein of T. virens and maize PR5, a thaumatin-like defence protein as predicted interacting partners (with cue from some plant-pathogen interactions). Using computational analysis, we test the hypothesis that Trichoderma Alt a 1 inactivates maize PR5 to suppress plant defence in order to be able to colonize roots. The tertiary structures of both Alt a 1 and PR5 were modelled through homology as well as de novo modelling, followed by model validation through different quality check tools. Prior to protein-protein docking, MD (molecular dynamics) optimisation and refinement of computational models were carried-out. Docking results indicated that Alt a 1 exhibits strong binding affinity with PR5 suggesting that Alt a 1 and PR5 might interact much like in a plant-pathogen interactions resulting in suppression of plant defence to facilitate colonization.

An invasive beetle\u2013fungus complex is maintained by fungal nutritional-compensation mediated by bacterial volatiles

Mutualisms between symbiotic microbes and animals have been well documented, and nutritional relationships provide the foundation for maintaining beneficial associations. The well-studied mutualism between bark beetles and their fungi has become a classic model system in the study of symbioses. Despite the nutritional competition between bark beetles and beneficial fungi in the same niche due to poor nutritional feeding substrates, bark beetles still maintain mutualistic associations with beneficial fungi over time. The mechanism behind this phenomenon, however, remains largely unknown. Here, we demonstrated the bark beetle Dendroctonus valens LeConte relies on the symbiotic bacterial volatile ammonia, as a nitrogen source, to regulate carbohydrate metabolism of its mutualistic fungus Leptographium procerum to alleviate nutritional competition, thereby maintaining the stability of the bark beetle–fungus mutualism. Ammonia significantly reduces competition of L. procerum for carbon resources for D. valens larval growth and increases fungal growth. Using stable isotope analysis, we show the fungus breakdown of phloem starch into d-glucose by switching on amylase genes only in the presence of ammonia. Deletion of amylase genes interferes with the conversion of starch to glucose. The acceleration of carbohydrate consumption and the conversion of starch into glucose benefit this invasive beetle–fungus complex. The nutrient consumption–compensation strategy mediated by tripartite beetle–fungus–bacterium aids the maintenance of this invasive mutualism under limited nutritional conditions, exacerbating its invasiveness with this competitive nutritional edge.

Colonization of Vitis vinifera L. by the Endophyte Trichoderma sp. Strain T154: Biocontrol Activity Against Phaeoacremonium minimum.

Trichoderma strains used in biological control products usually exhibit high efficiency in the control of plant diseases. However, their behavior under field conditions is difficult to predict. In addition, the potential of indigenous strains has been poorly assayed as well as their possible behavior as endophytes. Hence, niche colonization is a key feature for an effective protection. In this study, we aimed to: (i) explore the possibility of using a new Trichoderma strain isolated from vine to control pathogens, (ii) study the in planta interaction with the pathogen Phaeoacremonium minimum W. Gams, Crous, M.J. Wingf. & L. Mugnai (formerly Phaeoacremonium aleophilum), a pioneer fungus involved in Grapevine Trunk Diseases (GTDs) such as esca. For this purpose, fluorescently tagged Trichoderma sp. T154 and a P. minimum strain were used for scanning electron microscopy and confocal scanning laser microscopy analyses. Data showed that the Trichoderma strain is able to colonize plants up to 12 weeks post inoculation and is located in xylem, fibers, as well as in parenchymatic tissues inside the wood. The beneficial fungus reduced colonization of the esca-related pathogen colonizing the same niches. The main observed mechanism involved in biocontrol of Trichoderma against the esca pathogen was spore adhesion, niche exclusion and only few typical hypha coiling was found between Trichoderma and the pathogen. These results suggest that the Trichoderma strain has potential for reducing the colonization of Phaeoacremonium minimum and thus, an inoculation of this biological control agent can protect the plant by limiting the development of GTD, and the strain can behave as an endophyte.

The Influence of Human Interference on Zooplankton and Fungal Diversity in Poyang Lake Watershed in China

The Poyang water system in Jiangxi Province, China, is important for floodwater storage, diversity maintenance, and the economy of the Poyang Lake watershed. In recent years, pollution has destroyed the ecosystem and impacted human health and the related economy. The water quality of the Poyang Lake watershed and the impact of human interference must be assessed. Conventional analysis and high-throughput sequencing were used to evaluate the structure of both zooplankton and fungi in six sub-lakes of the Poyang Lake watershed under different anthropogenic influences. The sub-lakes included were Dahuchi Lake (in natural preserve, DHC), Shahu Lake (in natural reserve, SH), Nanhu Lake (out of natural preserve, NH), Zhelinhu Lake (artificial reservoir, ZLH), Sixiahu Lake (agricultural lake artificially isolated from Poyang Lake, SXH), and Qianhu Lake (urban lake, QH). The densities and biomass of the zooplankton in DHC, SH, NH were higher compared with those in SXH, ZLH and QH (p &lt; 0.05). Zooplankton distribution of SXH was the most strongly associated with total nitrogen (TN), total phosphorus (TP) and chlorophyll a (Chl a), while QH was highly associated with pH, conductivity (Cond), and water temperature (WT). For fungal diversity, a large number of beneficial fungi, Basidiomycota (phylum level) and Massarina (genus level) were obtained from DHC (55.3% and 27.5%, respectively), SH (54.4% and 28.9%, respectively), and NH (48.6% and 1.4%, respectively), while a large number of pathogenic Chytridiomycota (at phylum level) were identified from SXH (21.0%), ZLH (5.5%), and QH (7.5%). Manmade pollutants have impacted the natural hydrology and water quality and promoted variation between the zooplankton and fungi in the six sub-lakes, reducing the relative abundance of beneficial fungi and increasing the number of pathogens in the environment, which threatens human health and economic production. Understanding the diversity among the zooplankton and fungi in the six sub-lakes of the Poyang Lake watershed may help guide future water management practices.

Deletion of the Trichoderma virens NRPS, Tex7, induces accumulation of the anti-cancer compound heptelidic acid

The anticancer antibiotic heptelidic acid is a sesquiterpene lactone produced by the beneficial plant fungus Trichoderma virens. This species has been separated into two strains, referred to as P and Q, based on its biosynthesis of secondary metabolites; notably, only P-strains were reported to produce heptelidic acid. While characterizing a Q-strain of T. virens containing a directed mutation in the non-ribosomal peptide synthetase encoding gene Tex7, the appearance of an unknown compound in anomalously large quantities was visualized by TLC. Using a combination of HPLC, LC-MS/MS, and NMR spectroscopy, this compound was identified as heptelidic acid. This discovery alters the strain classification structure of T. virens. Additionally, the Tex7 mutants inhibited growth of maize seedlings, while retaining the ability to induce systemic resistance against the foliar fungal pathogen, Cochliobolus heterostrophus.