Endophytic Isolates Research Articles

Epigenetic Induction of Secondary Metabolites Production in Endophytic Fungi Penicillium chrysogenum and GC-MS Analysis of Crude Metabolites with Anti-HIV-1 Activity.

The continuous burden of human immunodeficiency virus-1 in Sub-Saharan Africa, coupled with the inability of antiretroviral agents to eradicate HIV-1 from viral reservoirs, the potential risks of drug resistance development, and the development of adverse effects, emphasizes the need to develop a new class of HIV-1 inhibitors. Here, we cultivated four endophytic fungal isolates from a medicinal plant, Albizia adianthifolia with the addition of small epigenetic modifiers, sodium butyrate, and valproic acid, to induce the expression of biosynthetic gene clusters encoding active secondary metabolites with probable anti-HIV activities. We identified a non-toxic crude extract of the endophytic fungus Penicillium chrysogenum treated with sodium butyrate to possess significantly greater anti-HIV activity than the untreated extracts. Penicillium chrysogenum P03MB2 showed anti-HIV activity with an IC50 of 0.6024 µg/mL compared to untreated fungal crude extract (IC50 5.053 µg/mL) when treated with sodium butyrate. The profile of secondary metabolite compounds from the bioactive, partially purified extracts were identified by gas chromatography-mass spectrometry (GC-MS), and more bioactive compounds were detected in treated P. chrysogenum P03MB2 fractions than in untreated fractions. Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro (13.64%), cyclotrisiloxane, hexamethyl (8.18%), cyclotetrasiloxane, octamethyl (7.23%), cyclopentasiloxane, decamethyl (6.36%), quinoline, 1,2-dihydro-2,24-trimethyl (5.45%), propanenitrile (4.55%), deca-6,9-diene (4.55%), dibutyl phthalate (4.55%), and silane[1,1-dimethyl-2-propenyl)oxy]dimethyl (2.73%) were the most abundant compounds. These results indicate that treatment of endophytic fungi with small epigenetic modifiers enhances the secretion of secondary metabolites with stronger anti-HIV-1 properties, acknowledging the feasibility of epigenetic modification as an innovative approach for the discovery of cryptic fungal metabolites which can be developed into therapeutic compounds.

Screening of biohydrogen producing endophytic fungi from biodiesel plants

ABSTRACTBiohydrogen from endophytic fungi constitutes an alternative biofuel resource with considerable advantages over biodiesel and ethanol extracted from existing food crops. Endophytes common in plant tissues mimic host physiological behavior and produce primary and secondary metabolites like oils and fats. Therefore, endophytes from 7 selected biodiesel plants, and 30 endophytic fungi isolated from 170 different plant parts were screened. The methodology included staining, lipid analysis, DNA isolation, molecular characterization, identification of fungal isolates by ITS sequences, biodiesel analysis, characterization of volatile organic compounds (VOCs), and statistical analysis. The fungal endophyte isolate SPSRJ28 was the most significant with an accumulation capacity of more than 20% of the total lipid content of its dry biomass, validating its oleaginous nature. In addition, the endophytes investigated in the present study yielded various VOCs that were validated by chromatography for both standards and isolates. When the VOCs were subsequently analyzed for their prospective usage as myco‐diesel, the presence of methane in the isolate SPSRJ28 was found to be highly significant. These findings remarkably support the investigation of endophytic fungi and their relationship with oleaginous plants as alternative sources of bioactive metabolites from microbial cell factories for myco‐diesel generation.

Inoculation and colonization of the entomopathogenic fungi, Isaria javanica and Purpureocillium lilacinum, in tomato plants, and their effect on seedling growth, mortality and adult emergence of Bemisia tabaci (Gennadius).

Entomopathogenic fungi (EPF) are natural enemies which affect insect population and have long been recognized as biological control agents against many insect pests. Some isolates have also been established as endophytes, benefiting their host plants without causing any symptoms or negative effects. Here we demonstrated two entomopathogenic fungal species, Isariajavanica (Frieder. & Bally) Samson & Hywel-jone 2005 and Purpureocillium lilacinum (Thom) Luangsa-ard, Hou-braken, Hywel-Jones & Samson (2011) as endophytes in tomato plants by using the seed inoculation method and examined their effect on plant growth, B. tabaci mortality, and adult emergence. Our study indicated that tomato seeds treated with a fungal suspension of I. javanica and P. lilacinum enabled their recovery from plant tissues (root, stem and leaf) up to 60 days after inoculation (DAI). Both endophytic isolates also caused significant mortality of adult B. tabaci on seedlings inoculated with, I. javanica (51.92±4.78%), and P. lilacinum (45.32±0.20%) compared to the control treatment (19.29±2.35). Adult emergence rates were significantly high in the control treatments (57.50±2.66%) compared to I. javanica (15.00±1.47%) and P. lilacinum (28.75±4.78%) treatments. This study provides evidence that endophytic isolates of I. javanica and P. lilacinum have a biocontrol potentials for used against whiteflies and could also explored as plant growth promoters.

ISOLATION OF ENDOPHYTIC BACTERIA FROM SOURSOP LEAF (Annona muricata) AND SECONDARY ANTIOXIDANT METABOLIT ACTIVITY TESTING

Free radicals are molecules or molecular fragments that contain unpaired electrons in the valence shell. To achieve stability, free radical molecules will react with surrounding molecules. Free radical molecules in the body take place continuously and are difficult to stop, this can cause diseases such as premature aging and cancer. Therefore, the required compound has antioxidant activity to stop it. One of the antioxidant compounds can be obtained by utilizing secondary metabolites of Soursop leaf endophytic bacteria (Annona muricata). Soursop leaf endophytic bacteria isolates have been obtained which have the form of diplobacillus and include gram-positive bacteria. The activity was carried out using the DPPH method and obtained IC50 of 278.27 ppm at the 22nd hour and 61.942 ppm at the 24th hour. The total phenolic obtained at the 22nd hour was 79 mgek of gallic acid/g while at the 24th hour it was 34 mgek of gallic acid/g. Secondary metabolites of soursop leaf endophytic bacteria produce secondary metabolites in the form of alkaloids and terpenoids.

Endophytic Fusarium species, a unique bioresource for disaggregator of misfolded alpha-synuclein.

Aggregation of α-synuclein into toxic oligomeric structures has been implicated in the pathogenesis of Parkinson's disease via several key stages of fibrillation, oligomerization, and aggregation. Disaggregation or prevention of aggregation has garnered a lot of attention as a therapeutic strategy to prevent or delay the progression of Parkinson's disease. It has been recently established that certain polyphenolic compounds and catechins present in plants and tea extracts exhibit the potential to inhibit the α-synuclein aggregation. However, their copious supply for therapeutic development is still unsolved. Herein, we report for the first time the disaggregation potential of α-synuclein by an endophytic fungus residing in tea leaves (Camellia sinensis). Briefly, a recombinant yeast expressing α-synuclein was used for pre-screening of 53 endophytic fungi isolated from tea using anti-oxidant activity as a marker for the disaggregation of the protein. One isolate #59CSLEAS exhibited 92.4% reduction in production of the superoxide ions, which were similar to the already established α-synuclein disaggregator, Piceatannol exhibiting 92.8% reduction. Thioflavin T assay further established that #59CSLEAS decreased the oligomerization of α-synuclein by 1.63-fold. Subsequently Dichloro-dihydro-fluorescein diacetate-based fluorescence assay exhibited a reduction in total oxidative stress in the recombinant yeast in the presence of fungal extract, thereby indicating the prevention of oligomerization. Oligomer disaggregation potential of the selected fungal extract was found to be 56.5% as assessed by sandwich ELISA assay. Using morphological as well as molecular methods, the endophytic isolate #59CSLEAS was identified as Fusarium sp. The sequence was submitted in the Genbank with accession number ON226971.1.

Antimicrobial activities of endophytic bacteria isolated from Ageratum conyzoides Linn.

Abstract. Boonman N, Chutrtong J, Wanna C, Boonsilp S, Chunchob S. 2023. Antimicrobial activities of endophytic bacteria isolated from Ageratum conyzoides Linn. Biodiversitas 24: 1971-1979. Endophytic bacteria were isolated from various parts of Ageratum conyzoides Linn. Total 35 isolates were obtained which were consisting of eight isolates from the roots (AconR1-AconR8), nine isolates from the stems (AconS1-AconS9), seven isolates from the leaves (AconL1-AconL7) and 11 isolates from the flowers (AconF1-AconF11). These endophytic bacteria were examined for their antimicrobial activities against human pathogenic bacteria and fungi. The AconR2 and AconR4 inhibited the growth of Shigella flexneri and Salmonella enterica ser. typhi, whereas Escherichia coli was only inhibited by AconR2. For the antifungal activities assay, all isolated endophytic bacteria revealed no effect on Candida albicans, while six endophytic isolates exhibited more than 80% mycelial growth inhibition against Microsporum canis. These highly effective isolates were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The Bruker scores revealed that AconR2 and AconR4 were identified as Pseudomonas aeruginosa, AconS1 and AconS6 were classified as Enterobacter asburiae, Acon L5 and Acon F9 were identified as Bacillus cereus. The results indicated that these endophytic bacteria isolated from A. conyzoides effectively inhibited the growth of human pathogenic filamentous fungi and showed promise for further development as novel antifungal agents.

IDENTIFICATION OF ENDOPYTIC FUNGI COMPOUND ON WHITE WEED LEAVES (Ageratum Conyzoides L.) CONTAINING THE POTENTIAL TO PRODUCE ANTIBIOTICS BY TLC-BIOAUTOGRAPHY.

White weed (Ageratum conyzoides L.) is known to have antibacterial elements containing chemical compound such as saponin and flavonoids. This study aimed to examine the antibiotic activity of endophytic fungi isolates of white weed leaves by the TLC-Bioautography method. The results of endophytic fungi isolation of white weed leaves obtained 10 isolates consisting of IFDP 1, IFDP 2, IFDP 3, IFDP 4, IFDP 5, IFDP 6, IFDP 7, IFDP 8, IFDP 9, and IFDP 10. The results of the macroscopic examination of the ten isolates of endophytic fungi found different characteristics. The results of the screening using 9 samples obtained isolates that found activity showing high inhibitory power, such as IFDP 1, IFDP 2, and IFDP 4 isolates. Isolates of IFDP 1, IFDP 2 and IFDP 4 were fermented on MYB medium for 14 days. Then filtering and evaporation were carried out to produce an extract. Isolate fermentate extracts were identified using Thin Layer Chromatography with chloroform eluent: methanol (4:2). The antibiotic activity test was done using TLC-Bioautography method, and obtained an Rf value in isolate 1, at Rf 0.74 on Vibrio cholerae. Isolate 2 resulted rf value of 0.67 on Salmonella thypi, Vibrio cholerae, Eschericia coli, disentriae, Staphylococcus epidermis. Isolate 4 generated an Rf value of 0.74 on Pseudomonas aeruginosa and Vibrio cholerae. While the group of active chemical components contained in the endophytic fungi isolates of white weed leaves was lavonoids by using AlCl3 reagents, AICI3 reagent alkaloids, and Sulfuric acid for saponin identification

ISOLATION OF ENDOPHYTIC FUNGI FROM PATCHOULI LEAVES (POGOSTEMON CABLIN BENTH) AS ANTIBACTERIAL AGAINST PATHOGENIC BACTERIA BY BIOAUTOGRAPHY AND AGAR DIFFUSION

Patchouli (Pogostemon cablin Benth) is a plant used as a substance in the pharmaceutical industry such as the manufacture of anti-inflammatory, antifungal, anti-insect and anti-inflammatory drugs. This study aimed to obtain endophytic fungi isolates having the potential as antibacterial by using TLC- Bioautography and agar diffusion methods. This research was conducted by isolating the endophytic fungi from Patchouli leaves and after that, purification and macroscopic tests were carried out and ten isolates were obtained pure. The results of the isolate screening test with codes IFDN 1, IFDN 3, IFDN 4, IFDN 6, IFDN 7, IFDN 8 and IFDN 9, showed the highest inhibition. Furthermore, the antibacterial activity was assayed by TLC-Bioautography. The results showed active spots (Rf 3 = 0.54; Rf 4 = 0.61; Rf 6 = 0.58; Rf 7 = 0.45; Rf 8 = 0.54; Rf 9 =0.47) against Eschericia coli, Staphylococcus aureus and Staphylococcus epidemics. The results of the antibacterial activity test by diffusion method obtained an inhibition zone for each bacterium, namely Staphylococcus aureus of 8.66 mm, Staphylococcus epidermidis of 8.38 mm, and Eschericia coli of12.23 mm.Key Words: Agar diffusion; Antibacterial; Endophytic fungi; skin infections; TLC Bioautograph.

ISOLATION OF ENDOPHYTIC FUNGI FROM PATCHOULI LEAVES (POGOSTEMON CABLIN BENTH) AS ANTIBACTERIAL AGAINST PATHOGENIC BACTERIA BY BIOAUTOGRAPHY AND AGAR DIFFUSION

Tunjuk Langit (Helminthostachys Zelanica (L) Hook.) is a plant with family Opioglossaceae traditionally and empirically used as antibacterial with chemical compound flavonoid and saponin. This research aims to determine antibacterial activity of endophytic fungi isolate of Tunjuk Langit (Helminthostachys Zelanica (L) Hook.) root on bacteria that cause gastrointestinal infections. The result of the isolation endophytic fungi against from Tunjuk Langit (Helminthostachys Zelanica (L) Hook.) root using PDA+C medium and purification isolate obtained 7 pure isolates and analysis macroscopic from 8 isolates (IFATL-01, IFATL-02, IFATL-03, IFATL-04, IFATL-05, IFATL-05, IFATL-06, IFATL-07 and IFATL-08) obtained different charasteristics. Production of secondary metabolites of isolate active (IFATL05) by fermentation unsing maltose yeast broth (MYB) obtained supernatant and miselia. Metabolites supernatant were extracted using ethyl acetat, so obtained extract ethyl acetate supernatan. The result of the antibacterial activity of isolate endophytic fungi against V. cholerae, S. dysenteriae and E. coli bacteria by Agar diffusion obtained the largest diameter of the inhibition zone in isolate IFATL-05 = 29.13 mm active against S. dysenteriae bacteria. Based on phytochemical screening f

Colonization and endophytic effect of Beauveria bassiana (Bals.-Criv.) Vuill. UHSB-END1 against Myzus persicae (Sulzer) and Plutella xylostella (L.) in cabbage

BackgroundFungal microbial biocontrol agent playing an important role in sustainable pest management with low cost. Conidial contact with cuticle is sufficient to cause disease in insects by entomopathogenic fungi (EPF) compared to bacteria and viruses which required ingestion of contaminated food. The field level application of fungi resulted inconsistent in their efficacy against insects as they withstand in the agroecosystem with adverse environmental conditions. To overcome this bottleneck, endophytic EPF, Beauveria bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae: Hypocreales), is well-studied for the management of insects of cultivated crops and got promising results. The colonization of endophytic isolates varied from one host plant to another and virulence against insects too. Hence, the study was undertaken to know the colonization of indigenous B. bassiana UHSB-END1 isolate in cabbage plant and its efficacy against major insects of cabbage.ResultsThe indigenous isolate of B. bassiana UHSB-END1 was able to colonize cabbage in all the methods of inoculations (seed treatment, seedling root dip, soil drenching, foliar spray and combination treatment) at 30, 45 and 60 days of post-inoculation (dpi). However, the colonization of the fungus inside the cabbage was restricted to tissues of inoculation, and movement from the site of inoculation to other parts of the plant was poor. In the present study, colonization was the highest at 30 dpi in all methods of colonization with restricted colonization to the site of exposure of fungus. Further, in vivo and in planta assay confirmed the effectiveness of B. bassiana UHSB-END1 colonized cabbage against Myzus persicae (Sulzer) and Plutella xylostella (Linnaeus). Under in vivo conditions the maximum mortality of M. persicae and P. xylostella was recorded at 30 dpi. It was decreased slightly at 45 dpi, and the lowest morality was recorded at 60 dpi. In planta experiment also proved better efficacy against both the test insects. Wherein mortality of M. persicae ranged from 22 to 36% five days after release (DAR), it was increased to 48–68% at 10 DAR and reached highest mortality rate at 15DAR (72–96%). Similarly, mortality of P. xylostella ranged from 14 to 24% after five DAR, and it was 27–44% at 10 DAR, and maximum mortality rate of larvae were recorded at 15 DAR (64–96%).ConclusionThe present study reported 100% colonization of cabbage plant by indigenous B. bassiana UHSB-END1 at 30 dpi in combination of treatment and showed a maximum efficacy in managing the population of major insects of cabbage. Introducing this indigenous isolate will pave a ray of hope in managing the both key insects (P. xylostella and M. persicae) in cabbage agroecosystem without disturbing the environment and further helps in production of cabbage with minimum pesticide residue for consumers.

The potential of endophytic bacteria isolated from atung fruit seeds as antibacterial against skin pathogens

Antibiotic resistance is one of the biggest threats to global health today. Estimated by 2050, antibiotic resistance will cause around 10 million deaths per year if alternative treatments have not been identified. This study was aimed to determine the potential of endophytic bacterial isolates from the seeds of atung fruit (Parinarium glaberrimum Hassk) as an antibacterial against skin pathogens Cutibacterium acnes and MDR Staphylococcus aureus, and Staphylococcus epidermidis. This research was a descriptive observational research with laboratory experimental methods. This study used isolates of endophytic bacteria isolated from the seeds of atung fruit which were tested with pathogenic bacteria. The results showed that 2 of 7 endophytic bacterial isolates were able to inhibit the growth of C. acnes with clear zone diameter of 4 mm and 9 mm, respectively, yet couldn’t able to inhibit MDR S. aureus and S. epidermidis. This study concluded that the 2 isolates (isolate BBA5 and BBA9) could have potential as antibacterial against C. acnes. While 5 other isolates had not been able to inhibit the whole pathogenic bacteria tested. An optimization is necessary in an effort to develop these isolates as antibacterial.

Antimicrobial activity of secondary metabolites produced by Colletotrichum species, an endophytic fungus on Vernonia amygdalina Del (fam. Asteraceae)

The emergence of antibiotic-resistant strains of microorganisms calls for research and the development of strategies to curb this menace. The screening of antimicrobial compounds from endophytic fungi is a promising way to meet the increasing threat of drug-resistant. This study aims at evaluating the antimicrobial activity of the endophytic fungal extract of Colletotrichum sp. from the leaves of Vernonia amygdalina (Del). Endophytic fungal isolation, cultivation, and identification were carried out using standard methods. Subsequently, fermentation and extraction of the secondary metabolites were done on a rice medium. About 1.2g of the fungal extract was subjected to vacuum liquid chromatography (VLC) using gradient-based elution; n-hexane and ethyl acetate followed by dichloromethane and methanol. The high-performance liquid chromatography (HPLC) analysis of the crude extract and VLC fractions were also carried out. Gel permeation chromatography using Sephadex LH-20 was carried out on Fraction JT2. Antimicrobial Assays for fraction JT4 and the Sephadex LH-20 fractions (JT2C – JT2E) were also carried out. The results were analyzed using Statistical Package for Social Sciences. The high-performance liquid chromatography (HPLC) analysis of the crude extract and VLC fractions revealed the presence of the five bioactive metabolites (acropyrone, beauvericin, indole-3-carbaldehyde, indolyl-3-acetic acid, and rocaglamid A). The result of the antimicrobial activity of the VLC fraction, JT4, showed that the fraction exhibited a significant inhibitory effect against Bacillus subtilis, Pseudomonas aeruginosa at 0.25 – 1 mg/ml (IZD) and antifungal activity against Aspergillus niger only at 0.0625 – 1 mg/ml (IZD). The result of the antimicrobial activity of the gel chromatographic fractions revealed a significant effect against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli at 0.0625 – 1 mg/ml and had no inhibitory effect against Bacillus subtilis, Aspergillus niger and Candida albicans. The results of this study show that endophytic fungi on V. amygdalina could be a potential source of bioactive compounds for the development of potential and effective antibiotics.

Biochemical identification of endophytic bacteria isolates from medicinal plant kayu jawa lannea coromandelica (houtt.) merr

Medicinal plants and their endophytes are a source of valuable bioactive compounds and their secondary metabolites which contribute to more than 80% of natural medicines available in the market. A plant that has long been used as a traditional medicinal herb for healing is the Kayu Jawa (Lannea coromandelica (Houtt) Merr). This study aimed to characterization and identification of endophytic bacterial isolates isolated from medicinal plants Kayu Jawa (L. coromandelica (Houtt.) Merr). This research is a laboratory experimental research. In total, 8 isolates were selected as representatives of the bacterial community living in the tissues of Kayu Jawa (L. coromandelica (Houtt.) Merr). The microscopic observation was performed by Gram staining. Biochemical identification was conducted using Vitek 2. The results showed that Bacillus was the dominant genus in this study followed by Staphylococcus and Pantoea. Based on the research that has been done, it can be concluded that the endophytic bacteria isolated from Kayu Jawa Lannea coromandelica (Houtt) Merr, six isolates belonging to Bacillus and another two belonging to Staphylococcus and Pantoea genera. However, for the exploration of this prospective application, it is very important to do a systematic study of the biological and distribution of endophytic bacteria in the host.

Ceropegia rupicola, Acokanthera schimperi, Jatropha variegate Antimicrobial, Cytotoxicity and Phytochemical

In Asian countries, a variety of medicinal plants are utilized in folk medicine for hemostatic and antiseptic. The methanolic extracts of Jatropha variegata, Acokanthera schimperi, and Ceropegia rupicolawere tested for the following purposes: first, isolation of endophytic fungi, second, antimicrobial and cytotoxicity activity, and third, phytoconstituents of the methanolic extract using the GC-Mass technique. The plants came from a variety of Yemeni locations. Endophytic fungus strains were isolated and identified using starch casein and potato dextrose agar medium. Methanol was used to extract the stem and leaves of the plants. The agar well diffusion method was used to test the antibacterial properties of the produced methanolic extracts against four Gram-negative bacteria, three Gram-positive bacteria, and one species of yeast. The IC50 values for the most promising extracts are calculated. The methanolic extracts were also subjected to a phytochemical screening by GC-Mass. A total of forty fungal endophyte isolates were isolated. Fusarium spp. (15), Phomaspp. (6), Alternaria alternata (5), White Sterile mycelia (6), Dark Sterile mycelia (6), Cochlioboluslunatus (1), and Mucor spp. (1). were found throughout the identification process. The highest yield extract was obtained from Jatropha variegate (45.4%), followed by Acokanthera schimperi (32.3%), and finally Ceropegia rupicola (20.5%). Only Gram-negative bacteria were found to have antibacterial activity, and the most effective extract was Acokanthera schimperi against the majority of microorganisms tested (8–18mm). The methanolic extracts of Jatropha variegate had the best antibacterial activity against Klebsiella pneumoniae ATCC 13883015, with a zone of inhibition (45 mm). Furthermore, Ceropegia rupicola extract had the highest inhibitory zone against Candida albicans ATCC 700012 (20mm). In addition, the IC50 results showed that the Jatropha variegate extract on A549 had an IC50 of 84.1ug/ml and a PC3 of 39.4ug/ml. The IC50 for Ceropegia rupicola extract was 49.4ug/ml in A549 cells and 34ug/ml in PC3 cells. Also, the screening for phytochemicals of the three plant extracts revealed the presence of many chemicals such as ethanol, formic acid, and others that may be responsible for the observed actions.

Biocontrol activity of endophytic bacteria from cocoa against Phytophthora sp. and Colletotrichum sp.

Cocoa (Theobroma cacao L.) and chili pepper (Capsicum annuum L.) are commonly cultivated by farmers, and in some cases, both crops are grown together in intercropping systems. The main pathogen infected cocoa is the Phytophthora sp. fungus, which causes fruit rot, stem cancer, and leaf blight, while Colletotrichum sp. causes anthracnose in chili pepper plants. The ability of endophytic bacteria to inhibit the growth of fungi and bacterial pathogens is well known. In this study, the biocontrol ability of endophytic bacteria against fungal pathogens was tested, and a biocontrol preliminary test was also observed by examining their potential inhibition on Chromobacterium violaceum called antiquorum sensing test. Endophytic bacteria were isolated from cocoa plants, while Phytophthora and Colletotrichum were isolated from cocoa and chili pepper plants that showed symptoms of fruit rot and anthracnose. A total of 34 endophytic bacterial isolates were successfully obtained, with 10 isolates from leaves (DK), 12 isolates from branches (RK), and 12 isolates from roots (KA) of cocoa plant ICCRI 4. Sixteen isolates showed quorum sensing ability, which AHL degradation index ranging from 0.44 – 1.56. Antagonistic tests showed that 11 out of 16 isolates had strong antibiosis against Phytophthora sp., with inhibition zones ranging from 0.6-1.35 cm. Meanwhile, 10 out of 16 isolates had strong antibiotics against Colletotrichum sp., with clear zones ranging from 0.6 – 1.1 cm. The three best endophytic bacterial isolates that had a combination of antiquorum sensing ability on C. violaceum and biocontrol against Phytophthora sp. and Colletotrichum sp. were RK 11, KA 1, and KA 8. [Keywords: antagonist, ahl lactonase, plant beneficial microorganism]

KARAKTERISASI DAN UJI POTENSI JAMUR ENDOFIT PADA DAUN BAWANG MERAH (Allium ascalonicum L.) SEBAGAI PENGENDALI PATOGEN Fusarium sp. dan Alternaria sp.

Shallot (Allium ascalonicum L.) is a horticultural commodity that has high economic value and is needed every day by the community. Attack by pets and pathogens on shallot cultivation cause a decrease in crop productivity. The pathogen that often attacks shallot plants is Fusariumsp. and Alternaria sp. This study aims to obtain endophytic fungi from shallot leaves that can control Fusarium sp. and Alternaria sp. The endophytic fungus isolation method uses healthy shallot leek samples while the pathogen isolation uses unhealthy leaves. The antagonism potency test was conducted using the dual culture method with an incubation time of 7 days at 25-30oC. Based on the results of the study, there were 4 isolates of endophytic fungi on shallot leaves, namely EA1 isolates (Aspergillus niger), EA2 isolates, EA3 isolates (Clasdoporium sp.) and EA4 isolates (Phyllosticta sp.). The results of the antagonist test showed that the endophytic fungus EA1 was able to inhibit the fungus Fusarium sp. and Alternaria sp. maximally (strong) with an average value of Fusarium sp. of 62.72% while Alternaria sp. 67.83 %. The endophytic fungus EA2 was also able to inhibit both of these pathogens but it was moderately categorized with an average value of Fusarium sp. 52.11 % and Alternaria sp. 53.28%. The mechanisms of inhibition are competition and hyperparasitism.

Endophytic Trichoderma species from rubber trees native to the Brazilian Amazon, including four new species.

Fungi belonging to the genus Trichoderma have been widely recognized as efficient controllers of plant diseases. Although the majority of isolates currently deployed, thus far, have been isolated from soil, endophytic Trichoderma spp. is considered to be a promising option for application in biocontrol. In this study, 30 endophytic Trichoderma isolates-obtained from the leaves, stems, and roots of wild Hevea spp. in the Brazilian Amazon-were analyzed using specific DNA barcodes: sequences of internal transcribed spacers 1 and 2 of rDNA (ITS region), genes encoding translation elongation factor 1-α (TEF1-α), and the second largest subunit of RNA polymerase II (RPB2). The genealogical concordance phylogenetic species recognition (GCPSR) concept was used for species delimitation. A phylogenetic analysis showed the occurrence of Trichoderma species, such as T. erinaceum, T. ovalisporum, T. koningiopsis, T. sparsum, T. lentiforme, T. virens, and T. spirale. Molecular and morphological features resulted in the discovery of four new species, such as T. acreanum sp. nov., T. ararianum sp. nov., T. heveae sp. nov., and T. brasiliensis sp. nov. The BI and ML analyses shared a similar topology, providing high support to the final trees. The phylograms show three distinct subclades, namely, T. acreanum and T. ararianum being paraphyletic with T. koningiopsis; T. heveae with T. subviride; and T. brasiliensis with T. brevicompactum. This study adds to our knowledge of the diversity of endophytic Trichoderma species in Neotropical forests and reveals new potential biocontrol agents for the management of plant diseases.

Aspergillus flavus from coffee in Cameroon: a non-aflatoxigenic endophytic isolate antagonistic to coffee leaf rust (Hemileia vastatrix).

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

Penicillium citrinum, a Drought-Tolerant Endophytic Fungus Isolated from Wheat (Triticum aestivum L.) Leaves with Plant Growth-Promoting Abilities.

Endophytic fungi have recently garnered significant attention as next-generation bioinoculants due to their plausible role in ameliorating abiotic and biotic stresses. This adaptation is achieved via various signalling molecules and mechanisms established by these symbionts with their hosts. The present study screened 61 endophytic isolates of culturable mycobiome associated with wheat variety PBW725 during their crop cycle. Three endophytic isolates exhibited a minimum reduction in their growth and maximum biomass production during the drought stress developed using polyethylene glycol 6000. Further, these isolates also exhibited plant growth promoting properties by virtue of the production of indole acetic acid, gibberellic acid and ammonia. These isolates also exhibited the propensity to solubilise phosphate and zinc, produce siderophores and further exhibit extracellular enzymatic activities, contributing to plants' adaptability to abiotic stresses. The best isolate amongst the three was #5TAKL-3a, identified as Penicillium citrinum based on multilocus phylogenetic analysis. The isolate as a bioinoculant enhances various biochemical and physiological properties in planta. Hence our studies indicate that Penicillium citrinum #5TAKL-3a is a potential candidate bioinoculant for field trials to improve the adaptability of the wheat plant under drought stress.

Antagonistic, plant growth promoting and extracellular hydrolytic enzyme activity of fungal endophytes of Dioscorea bulbifera L.

Fungal endophytes can be considered as a new source of biological control and plant growth promoting agents. Moreover, the huge repertoire of extracellular enzymes produced by them has great biotechnological importance in medicine, agriculture and industry. The current study aimed at the assessment of plant growth promotion and biocontrol potential of endophytic fungal isolates associated with Dioscorea bulbifera L. for efficiently improved plant growth and protection of hosts from various infections. Overall, the experimental work revealed significant results where, 81% of the endophytic fungal isolates exhibited biocontrol potential against atleast one or more bacterial pathogens. The endophytic fungal isolate ARW2 (Clonostachys pseudochroleucha) was found to be highly effective against Gram positive bacteria whereas N4 (Parathyridaria percutanea) and H1B (Curvularia lunata) were effective against Gram negative bacteria. 52% of the endophytic fungal isolates were found to possess strong inhibition potential against fungal pathogens. H22 (F. proliferatum) and G8 (F. equiseti) demonstrated strong inhibition potential with percent inhibition ranging from 50 to 70%. The plant growth promoting activity of endophytic fungal isolates depicted that 52%, 27% and 2% isolates were capable of siderophore production, phosphate solubilisation and HCN production respectively. A quantitative estimation of IAA production revealed that almost all the isolates were producing IAA ranging from 1.2 to 200 μg/mL. Further assessment of extracellular enzymatic potential revealed that 37.5%, 31%, 18%, 12.5% and 4% of the endophytic fungal isolates exhibited activity positive results for amylase, lipolytic, protease, cellulolytic and chitinase activity, respectively. Our results indicate that these endophytic fungal isolated can be a promising source for future applications in medicine, agriculture and industry.