Root Endophyte Shift and Key Genera Discovery in Rice under Barnyardgrass Stress

Despite increasing knowledge of barnyardgrass(Echinochloa crus-galli) interference with rice, relatively little is known how endophytes improve the ability of rice against barnyardgrass stress. Here, we provided a detailed temporal characterization of rice root-associated microbiomes during co-cultivation with barnyardgrass and a comparison with the microbiomes of weed-free rice plants. Alpha diversity analysis indicated that barnyardgrass had the opposite effects on endophytic bacteria and fungi in rice roots, in terms of the community diversity, richness and coverage at the rice seedling stage. Principal coordinate analysis showed that barnyardgrass had only a minor effect on the community composition of endophytes in rice roots at the rice seedling stage, but showed a significant and maximum interference at the heading stage. Rice recruited many endophytes to resist biotic stress from barnyardgrass, especially for fungi. PICRUSt(phylogenetic investigation of communities by reconstruction of unobserved states) predictive analysis indicated that 23 metabolic pathways of bacteria were overrepresented in rice. In addition, the main trophic mode of fungi was pathotroph according to FUNGuild analysis. A positive correlation between bacteria and fungi in rice roots was found via network analysis. Anaeromyxobacter, Azospira and Pseudolabrys were the vital bacteria, Phaeosphaeria and Funneliformis were the dominant fungi in maintaining the stability of the ecological network. These results provided data and a theoretical basis for the in-depth understanding of what role endophytes play in rice resistance to barnyardgrass stress and will have implications on improving the resistance of rice against biotic stress using root microbiota.

Diversity Analysis of Endophytes in Wheat Infected by Powdery Mildew

Common wheat (Triticum aestivum L.) is one of the most important food crops. Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most serious diseases on wheat. In this study, the changes of endogenous bacteria in root, stem and leaf tissues of wheat infected and uninfected with powdery mildew were measured based on 16S rDNA. Integration, OTU cluster analysis, taxonomic analysis, diversity index, Shannon-Index curve, Rank-Abundance curve and PCoA analysis were carried out for each sample, and the roots, stems and leaves of different tissue parts were classified and summarized. The results showed that the infection of wheat powdery mildew had a certain effect on endophytic bacteria in stem tissue. There are also differences in the control and treatment of leaf tissue and root tissue. This indicated that endophytic bacteria were distributed differently in different parts of wheat.

Nature’s Pharmacy under Siege: Investigating Antibiotic Resistance Pattern in Endophytic Bacteria of Medicinal Plants

Antibiotic resistance poses a significant global health threat, necessitating a thorough understanding of its prevalence in various ecological contexts. Medicinal plants, renowned for their therapeutic properties, host endophytic bacteria that produce bioactive compounds. Understanding antibiotic resistance dynamics in these bacteria is vital for human health and antibiotic efficacy preservation. In this study, we investigated antibiotic resistance profiles in endophytic bacteria from five medicinal plants: Thankuni, Neem, Aparajita, Joba, and Snake plant. We isolated and characterized 113 endophytic bacteria, with varying resistance patterns observed against multiple antibiotics. Notably, 53 strains were multidrug-resistant (MDR), with 14 exhibiting extensive drug resistance (XDR). Thankuni-associated bacteria displayed 44% MDR and 11% XDR, while Neem-associated bacteria showed higher resistance (60% MDR, 13% XDR). Aparajita-associated bacteria had lower resistance (22% MDR, 6% XDR), whereas Joba-associated bacteria exhibited substantial resistance (54% MDR, 14% XDR). Snake plant-associated bacteria showed 7% MDR and 4% XDR. Genus-specific distribution revealed Bacillus (47%), Staphylococcus (21%), and Klebsiella (11%) as major contributors to MDR. Our findings highlight diverse drug resistance patterns among plant-associated bacteria and underscore the complexity of antibiotic resistance dynamics in diverse plant environments. Identification of XDR strains emphasizes the severity of the antibiotic resistance problem, warranting further investigation into contributing factors.

海南红树林内生真菌Endomelanconiopsis endophytica次级代谢产物及其体外生物活性

【目的】研究源自海南红树林植物角果木(Ceriops tagal)内生真菌Endomelanconiopsis endophytica的次级代谢产物及其体外生物活性。【方法】利用正相硅胶柱层析、反相ODS柱层析、Sephadex LH-20凝胶柱层析、半制备高效液相色谱等色谱分离方法,对该菌发酵产物的乙酸乙酯浸膏的次级代谢产物进行分离纯化;综合利用核磁共振波谱(NMR)、质谱(MS)等波谱学技术以及与文献数据比对,鉴定化合物的结构;并对化合物进行体外细胞毒活性和免疫抑制活性评价。【结果】从内生真菌Endomelanconiopsis endophytica中分离得到9个化合物,其结构分别鉴定为(4E,8E)-2-N-(2-hydroxypalmitoyl)-1-O-(β-D-glucopyranosyl)-9-methyl-4,8-sphingadienine(Ⅰ)、2-(1-hydroxyethyl)quinazolin-4(3H)-one(Ⅱ)、uridine(Ⅲ)、citreoisocoumarinol(Ⅳ)、5-hydroxymellein(Ⅴ)、roccellatol(Ⅵ)、dibutylphthalate(Ⅶ)、p-hydroxybenzoic acid(Ⅷ)、daucosterol(Ⅸ);化合物Ⅱ、Ⅵ、Ⅷ、Ⅸ对人肿瘤细胞A549和HepG2具有一定的体外抗增殖活性,其中化合物Ⅸ对人肝癌细胞HepG2有显著的细胞毒活性,IC_(50)值为(0.87±0.41)μmol/L;化合物Ⅰ~Ⅸ均无免疫抑制活性。【结论】化合物Ⅰ、Ⅸ为首次从Endomelanconiopsis属菌中分离得到,化合物Ⅸ具有显著的体外细胞毒活性。

Diversity of endophytes across the soil-plant continuum for Atriplex spp. in arid environments

Endophytes are hypothesized to be transferred across the soil-plant continuum, suggesting both the transfers of endophytes from environment to plant and from plant to soil. To verify this hypothesis and to assess the role of locality, we evaluated the similarity of microbial communities commonly found both in soils and endophytic communities in three arid regions, i.e. the Jornada LTER （Long Term Ecological Research） site in New Mexico, USA, and the research station of Jordan University of Science and Technology （JUST） and Khanasd research station in Badia region of Jordan. Rhizosphere and non-rhizosphere soils, leaves and seeds of Atriplex spp. were sampled. Diversity and distribution of bacteria and fungi across the soil-plant continuums were assessed by tag-encoded FLX amplicon pyrosequencing and sequence alignment. Of the total bacterial OTUs （operational taxonomic units）, 0.17% in Khanasri research station, 0.16% in research station of JUST, and 0.42% in Jornada LTER site were commonly found across all the plant and soil compartments. The same was true for fungi in two regions, i.e. 1.56% in research station of JUST and 0.86% in Jornada LTER site. However, in Khanasri research station, 12.08% of total fungi OTUs were found in at least one soil compartment and one plant compartment. Putative Arthrobacter, Sporosarcina, Cladosporium and members of Proteobacteria and Actinobacteria were found across all the soil-plant continuums. Ascomycota, mainly including Didymellaceae, Pleosporaceae and Davidiellaceae were present across all the soil-plant continuums. Microbial communities in two regions of Jordan were similar to each other, but both of them were different from the Jornada LTER site of USA. SIMPER （similarity percentage） analysis of bacterial and fungal taxa for both soil and endophyte communities revealed that dissimilarities of two bacterial genera （Arthrobacter and Sporosarcina） and two fungal genera （Cladosporium and Alternaria） are very high, so they play key roles in the soil-plant continuums. A weighed Pearson correlation analysis for the specific bacterial OTUs in the soil-plant continuums only showed high similarity between the two regions of Jordan. However, fungal groups showed higher similarities among all regions. This research supports the hypothesis of continuity of certain bacterial and fungal communities across the soil-plant continuums, and also explores the influences of plant species and geographic specificity on diversity and distribution of bacteria and fungi.

Endophytes as Producers of Peptides:An Overview About the Recently Discovered Peptides from Endophytic Microbes

An endophyte is a fungus or bacterium that lives within a plant in a symbiotic relationship.Extensive colonization of the plant tissue by endophytes creates a barrier effect,where they outcompete and prevent pathogenic organisms from taking hold.This happens by producing secondary metabolites that inhibit the growth of the competitors or pathogens.In this way they play a very important role in the plant defence mechanisms.The metabolites produced by these endophytes fall within a wide range of classes of compounds that include peptides which are the focus of this review.Peptides are increasingly being selected for drug development because they are specific for their targets and have a higher degree of interactions.There have been quite a number of endophytic peptides reported in the recent past indicating that endophytes can be used for the production of peptide based drugs.Molecular screening for NRPS,which shows peptide producing capability,has also shown that endophytes are potential producers of peptides.The presence of NRPS also offers the possibility of genetic modifications which may generate peptides with high pharmacological activities.This review,therefore,aims to show the current status of peptides isolated from endophytic bacteria and fungi in the recent decade.Endophytes as potential sources of peptides according to NRPS studies will also be discussed.

Tree species as hosts for arbuscular mycorrhizal and dark septate endophyte fungi

A survey of 35 tree species （belonging to 28 genera in 19 families） in Aliyar, South India was carried out to ascertain their arbuscular mycorrhizal （AM） and dark septate endophyte （DSE） fungal status. All the tree species examined had AM association. AM and DSE coloni- zation is reported for the first time in 20 and 14 species respectively. Co- occurrence of AM and DSE was observed in 14 （40%） tree species. The extent of DSE colonization was inversely related to the extent of AM fungal colonization. Six tree species had Arum-type, 18 had intermediate- type and 11 had typical Paris-type AM morphology. AM fungal spore morphotypes belonging to 11 species in two genera were isolated from the rhizosphere soil. AM fungal spore numbers were not related to the ex- tent of AM colonization and Glomus dominated spore diversity. AM association individually and along with DSE were found respectively in the 63% and 44% of the economically important tree species. The occur- rence of AM and DSE fungal association in economically important indigenous tree species indicates the possibility of exploiting this asso- ciation in future conservation programmes of these species.

Non-mycorrhizal fungal endophytes in two orchids of Kaiga forest(Western Ghats), India

We used standard isolation protocols to explore the endophytic fungal communities in three tissue types of two dominant orchids （Bulbophyllum neilgherrense and Vanda testacea） of the Kaiga forest of the Western Ghats. We surface sterilized and assessed 90 segments of each orchid for the occurrence and diversity of endophytic fungal taxa. The 118 fungal isolates were obtained from root, bulb and leaves of B. neilgherrense, consisting of 17 anamorphic taxa （range, 10-15 taxa） with 1.3 fungal taxa per segment （range, 1.2-1.4 taxa）. Four taxa （Aspergillus flavus, A. niger, Penicillium sp. and morpho sp. 1） belonged to the core group （11.1%--32.2%）. The relative abundance of A. flavus and morpho sp. 1 was more than 10%. A total of 130 fungal isolates from roots, stems and leaves of V. testacea yielded 20 anamorphic taxa （range, 11-15 taxa） with 1.4 fungal taxa per segment （range, 1.4-1.5 taxa）. Aspergillusflavus, A. niger, A. ochraceus, Gliocladium viride, Penicillium sp. and morpho sp. 1 belonged to the core group. Relative abundance exceeded 10% for A. flavus, A. niger, and morpho sp. 1. The Simpson and Shannon diversity indices were higher in leaf than root or bulb/stem of both orchids. Jaccard＇s similarity coefficient was higher between root and leaf in both orchids （56.3%-60%） than between other pairs. Our study revealed that the endophytic fungal assemblage and diversity orB. neilgherrense and E testacea of Kaiga forest of the Western Ghats were relatively similar between orchids and their tissues.

The osmolyte-producing endophyte Streptomyces albidoflavus OsiLf-2 induces drought and salt tolerance in rice via a multi-level mechanism

Drought and salinity are major environmental stresses that impair crop growth and productivity worldwide. Improving drought and salt tolerance of crops with microbial mutualists is an effective and environmentally sound strategy to meet the demands of the ever-growing world population. In the present study, we found that the Streptomyces albidoflavus Osi Lf-2, a moderately salt-tolerant endophytic actinomycete, produced abundant osmolytes, including proline, polysaccharides, and ectoine. Inoculation with Osi Lf-2 increased the osmotic-adjustment ability of the rice host by increasing the proline content(by250.3% and 49.4%) and soluble sugar(by 20.9% and 49.4%) in rice under drought and salt conditions, relative to the uninoculated control. Osi Lf-2 increased stress responses in the rice host at the physiological and biochemical levels(photosynthesis efficiency, osmolytes and antioxidant content), and the gene level(osmolytes synthesis, stress-responsive and ion-transport related genes), raising rice yields under both greenhouse and saline–alkaline soil conditions. The use of endophytic actinomycetes offers a promising biotechnological approach to developing stress-tolerant plants.

Testing of Bacterial Endophytes from Non-Host Sources as Potential Antagonistic Agents against Tomato Wilt Pathogen <i>Ralstonia solanacearum</i>

The study was taken up with the objective of testing whether the endophytic organisms isolated from crops that are normally non-hosts to the bacterial wilt pathogen Ralstonia solanacearum possessed pathogen-antagonistic activity and to evaluate the selected isolates for the alleviation of wilt disease in the target tomato crop through horizontal movement of promising organisms. Sixteen endophytic bacteria (EB) isolated from the micropropagated cultures of grape, watermelon and papaya were tested for potential antagonistic effects against R. solanacearum tomato isolate “NH-01” through agar-well diffusion assay. Enterobacter cloacae from papaya (EB-11) displayed the maximum antagonistic effect followed by Bacillus subtilis (EB-06) and B. flexus (EB-07) from watermelon and B. pumilus (EB-02) from grape. Testing the above organisms for crop protection through seed fortification of susceptible tomato cv. Arka Vikas at sowing in R. solanacearum inoculated (Ral+) organic cocopeat showed EB-02 and EB-11 promising (33% and 32% survival, respectively, four weeks after sowing against 15% in Ral+ control). A second trial showed 37%, 28%, 21% and 55% seedling survival 6 weeks after sowing for EB-02, EB-06, EB-07 and EB-11 respectively, compared to 2.5% in non-treated control. Assessing the four endophytes for crop protection in Ral+ sick-soil through seedling fortification at transplanting indicated less disease incidence in treated sets (40%, 40%, 20% and 20% survival, respectively, six weeks after transplanting) over non-fortified control (5%). Endophytic fortification of seedlings through hypocotyl inoculation showed some systemic resistance induction upon seedling transplanting to sick soil but not with petiole fortification. Seedling growth was enhanced by the isolates EB-06 and EB-07. The study thus identifies four endophytic organisms from crops unrelated to tomato possessing potential antagonistic activity against the wilt pathogen and prospects for exploitation as biocontrol agents coupled with seedling growth promotion effects.

Isolation and Identification of Bacterial Endophytes from Grasses along the Oregon Coast

Bacterial endophytes have been shown to improve abiotic and biotic stress responses in plants. Plants growing under harsh conditions along the Oregon Coast could contain bacterial endophytes that improve persistence and growth of grasses in this environment. Thirty-four plants consisting of eight different species were collected along the Oregon coast from four different sites. Bacterial endophytes were isolated from root crown, stem and leaf tissues. A portion of the 16S rRNA ITS regions of each isolate was amplified, sequenced, and used to perform a BLAST search against the nucleotide database collection at National Center for Biotechnology Information. One-hundred and thirty-three different bacterial isolates, ninety-four of which were unique, representing thirty-six different taxonomic groups were found. Over 50% of the total bacteria isolates were in just five taxonomic groups. Pseudomonads were the most predominant bacteria isolated, making up 20.3% of the total isolates, followed by Curtobacterium and Microbacterium, each at 8.2%, Bacillus at 7.5% and Xanthomomas at 6%. Forty-seven percent (17 of 36) of the taxonomic groups contained only a single isolate. Fourteen bacterial isolates from five taxonomic groups, nine of which were from the genus Pseudomonas, were found to have 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, an enzyme associated with improving plant growth under stress. These newly discovered bacterial endophytes will be a valuable biological resource to develop approaches to increase the yield and adaptability of grasses and other crops grown in diverse environments and to meet the challenges associated with an unpredictable climate.

Two New Alkaloids from Fusarium tricinctum SYPF 7082,an Endophyte from the Root of Panax notoginseng

Panax notoginseng(Araliaceae)is a famous traditional Chinese medicine mainly cultivated in Yunnan and Guangxi provinces of China.Two new alkaloids,rigidiusculamide E(1)and[-(a-oxyisohexanoyl-N-methyl-leucyl)2-](2),together with two known ones,(-)-oxysporidinone(3)and(-)-4,60-anhydrooxysporidinone(4)were isolated from the mycelia culture of Fusarium tricinctum SYPF 7082,an endophytic fungus obtained from the healthy root of P.notoginseng.Their structures were determined on the basis of extensive spectroscopic analyses.Compounds 1-4 were tested for their inhibitory effects against NO production on Murine macrophage cell line,and the new compound 2 showed significant inhibitory activity on NO production with the IC_(50)value of 18.10±0.16μM.

Transcriptome analysis for understanding the mechanism of dark septate endophyte S16 in promoting the growth and nitrate uptake of sweet cherry

Sweet cherry is one of the most popular fresh fruits in the world.Previously,we isolated a soilborne dark septate endophyte(DSE)strain,S16,which promoted the growth of Gisela 5 sweet cherry rootstock.However,little is known about the molecular mechanism of the effect of S16 on the growth of sweet cherry.In this study,the physiological parameters and transcript profiles of sweet cherry roots were analyzed under S16 treatment compared with a control to elucidate the molecular mechanisms of the effect of this strain on sweet cherry growth.After inoculation with S16,sweet cherry seedlings exhibited more vigorous growth.Moreover,we identified 4249 differentially expressed genes(DEGs)between S16-treated plants and the control.Many of the DEGs are involved in pathways related to plant growth,such as cellular metabolic and plant hormone pathways.Additionally,some genes involved in nitrate regulation were also enriched;and these genes may be involved in the regulation of nitrate uptake in plants.Physiological index detection demonstrated that S16 could improve the nitrate assimilation of sweet cherry via NO3–transporters.This RNA-seq dataset provides comprehensive insight into the transcriptomic landscape to reveal the molecular mechanisms whereby the DSE influences the growth of sweet cherry.

<i>In Vitro</i>Anti-HIV Activity of Partially Purified Coumarin(s) Isolated from Fungal Endophyte, <i>Alternaria</i>Species of <i>Calophyllum inophyllum</i>

5 totally different endophytic fungal species were isolated from bark and leaf parts of Calophyllum inophyllum. Leaf part yielded Trichoderma harzianum and Alternaria species, whereas bark showed the presence of Fusarium species, Aspergillus species and unidentified fungi. Two solvents (hexane and methanol) were used for endophytic fungal extraction and the Alternaria species had shown the presence of coumarin whereas Trichoderma harzianum in methanol extract and Fusarium species in hexane extract had shown the coumarin(s) in all the four methods tested. The total coumarin yield was more in microwave assistance method, the methanol Alternaria species (3.941 ± 0.082) stood first, followed by hexane extract of Alternaria species (3.254 ± 0.082), Fusarium species (2.532 ± 0.082) and Trichoderma harzianum (2.294 ± 0.082), the plant extract showed 4.149 + 0.053. The methanol extract of Alternaria species inhibited the activity of HIV-Reverse Transcriptase (RT) (82.81 ± 1.0), integrase (98%) and protease (78) in maximum level followed by hexane extract of Alternaria species (71.12 ± 0.9, 89, 68), Fusarium species (63.92 ± 1.8, 67, 66) and Trichoderma harzianum (56.69 ± 0.9, 71, 63). The endophytic fungi Alternaria species inhibited all the three viral enzymes at maximum level and it was more than standard drug. However, in order to know possible anti-HIV, it is necessary to isolate active coumarin from the Alternaria species and the mechanism of action will be studied in future studies.

Anti‑leishmanial and Anti‑inflammatory Agents from Endophytes:A Review

Leishmaniases and chronic inflammatory diseases are the cause of millions of deaths in the world each year.The treatment of leishmaniasis is facing serious drawbacks particularly due to the limited number of effective medicines,the resistance,and the toxicity of available drugs.On the other hand,many drugs are used for the management of inflammatory disorders.However,the most commonly prescribed although efficient is highly toxic with multiples side effects.New leads compounds for the development of new anti-leishmanial and anti-inflammatory drugs are needed.Over the past decade,several studies on the potential of endophytes to produce bioactive metabolites have been reported.We are presenting in the present review the status of research from 2000 to 2019 on the anti-leishmanial and anti-inflammatory metabolites isolated from endophytes from diverse habitats.An emphasis was put on existing gaps in the literature to inspire and guide future investigations.We hope that this review will help accelerate the drug discovery against leishmaniases and inflammation-associated disorders.

Taxol Determination from Pestalotiopsis pauciseta, a Fungal Endophyte of a Medicinal Plant

Taxol is the most effective antitumor agent developed in the past three decades.It has been used for effective treatment of a variety of cancers.A taxol-producing endophytic fungus Pestalotiopsis pauciseta(strain CHP-11) was isolated from the leaves of Cardiospermum helicacabum and screened for taxol production.The fungus was identified based on the morphology of the fungal culture and the characteristics of the spores and screened for taxol production.The amount of taxol produced by this endophytic fungus was quantified by HPLC and it produced 113.3 μg/L,thus the fungus can serve as a potential material for fungus engineering to improve taxol production.This fungal taxol also had strong anticancer activity against some cancer cells viz.,BT 220,H116,Int 407,HL 251 and HLK 210 tested by Apoptotic assay and it is indicated that with the increase of taxol concentration from 0.005-0.05 μmol/L,taxol induced increased cell death through apoptosis.

Antimicrobial Activity of Ulva reticulata and Its Endophytes

Seaweeds are known to exhibit various antimicrobial properties,since it harbours an enormous range of indigenous bioactive compounds.The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes,thereby exploiting the properties in resisting bacterial diseases.The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate,for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa,Salmonella typhi,and Bacillus subtilis.It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli.Further,Gas chromatography coupled with Mass spectroscopy(GC-MS) revealed the existence of phenol,3,5-bis(1,1-dimethylethyl) in the crude hexane extract which is well-known to possess antibacterial activity.The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas stutzeri by phenotypic and genotypic methods.The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens.The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS.The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts.Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.

禾草Epichloё属内生真菌分类学研究进展

禾草内生真菌(Epichloё属)是指在宿主禾草的组织间隙内完成其全部或大部分生命周期,但不引起宿主禾草产生外部明显症状的一类真菌。其作为重要的农业微生物资源,一方面能促进宿主植物的生长、提高宿主对不良环境的抵抗能力;另一方面,部分内生真菌与宿主形成的共生体所产生的部分生物碱可引致草食家畜中毒,影响草地畜牧业的健康发展。禾草内生真菌的这一双重特性已经成为国际草业领域近30年来的研究热点。本文首先综述了有性型和无性型Epichloё属禾草内生真菌的命名历史和分类现状,其次对我国目前已发现的禾草内生真菌资源及其分布以及禾草内生真菌在抗逆育种方面的研究进展进行归纳总结,最后针对禾草Epichloё属内生真菌的分类和应用进行了展望,以期为挖掘和利用有益禾草内生真菌资源、培育优良植物新品种、发展现代草地畜牧业和生态环境建设提供科学依据。

Root-associated endophytic fungi modulate endogenous auxin and cytokinin levels to improve plant biomass and root morphology of trifoliate orange

Root-associated endophytic fungi like Serendipita indica and arbuscular mycorrhizal(AM) fungi can improve plant growth and root construction, but the potential mechanism is unclear. In this study, Funneliformis mosseae(an AM fungus) and S. indica, singly or in combination were inoculated into trifoliate orange(Poncirus trifoliata) seedlings, to assess changes in biomass and root morphological traits, coupled with auxins and cytokinins concentrations in leaves and roots and the expression of auxin synthesis and transporter protein genes. After 20 weeks of inoculation with these fungi, shoot and root biomass, root total length, taproot length, average diameter, surface area, volume, and the number of lateral roots in 1st-, 2nd-, and 3rd-order were improved, and S. indica showed a relatively greater effect than F. mosseae and dual inoculation. Endophytic fungal inoculation also significantly increased the concentration of indoleacetic acid, indole butyric acid, trans-zeatin,dihydrozeatin, and isopentenyl adenine in leaves and roots, whilst F. mosseae and S. indica exhibited relatively greater effects on leaves and roots, respectively. Correlation analysis revealed that both biomass and root morphological traits(except root projected area) were significantly positively associated with endogenous auxins and cytokinins. In addition, the inoculated plants recorded comparatively higher expression levels of indoleacetic acid synthesis genes(PtTAA1, PtTAR2, PtYUC3, PtYUC4, PtYUC6, and PtYUC8) and indoleacetic acid transporter protein genes(PtAUX1, PtLAX1, PtLAX2, PtLAX3, PtPIN1, PtPIN3, PtPIN4, PtABCB1, and PtABCB19) than the non-inoculated plants, among which F. mosseae and S. indica showed better effects in leaves and roots, respectively. These results suggest that root-associated endophytic fungi improved plant growth and root architecture, which were associated with changes in endogenous auxins and cytokinins.

Fungal endophytes in green coffee seeds

Green coffee seeds from Colombia, Guatemala, India, Kenya, Papua New Guinea, Puerto Rico and Vietnam were sampled for the presence of fungal endophytes. Stions of surface sterilized seeds were plated on yeast malt agar, and fungal growth was isolated for subsequent DNA extraction and sequencing. Several fungal genera were isolated, including Acremonium, Aspergillus, Eurotium, Fusarium, Gibberella, Penicillium, Pseudozyma and an undescribed clavicipitaceous species. The biological activities that these fungi might be playing in coffee seeds remain unknown, but in other plants some of the genera isolated have been reported to protect against plant pathogens.