Aug 2026· IOP Conference Series: Earth and Environment· Vol 1664· 0 citations· 30 references
Physics
TL;DR
Among 14 endophytic isolates, Bacillus subtilis LS1-5 showed the strongest antifungal activity by dual culture assay, and exhibited a broad array of plant growth-promoting and environmental resilience traits.
Abstract
Endophytic bacteria represent a promising, sustainable alternative to synthetic agrochemicals for plant disease management by actively antagonizing phytopathogens and stimulating host immune responses. Despite its traditional use as an antimicrobial remedy, Wedelia chinensis remains underexplored as a source of beneficial endophytes. This study aimed to isolate and screen endophytic bacteria from W. chinensis for their antifungal activity against Fusarium oxysporum. Among 14 endophytic isolates, Bacillus subtilis LS1-5 showed the strongest antifungal activity by dual culture assay. Its cell-free culture filtrate effectively inhibited fungal spore germination by 91.3% at a 20% concentration. Crucially, B. subtilis LS1-5 produced several extracellular enzymes, including cellulase, amylase, chitinase, pectinase, gelatinase, lipase, and protease. Furthermore, the LS1-5 strain exhibited a broad array of plant growth-promoting and environmental resilience traits. Notably, it synthesized indole-3-acetic acid (IAA) at 2.11 ± 0.27 µg/mL in an LB medium without L-tryptophan, significantly promoted a 34.19% increase in root elongation, and demonstrated remarkable tolerance to extreme conditions, including high salinity (11% NaCl) and broad pH levels ranging from 6 to 12. Additionally, volatile organic compounds (VOCs) emitted by LS1-5 significantly inhibited the severe bacterial pathogens Xanthomonas oryzae (45.83%) and Xanthomonas citri (47.99%). These findings highlight B. subtilis LS1-5 as a highly effective candidate for biological control and sustainable agricultural applications.
This is the first report describing Bacillus stercoris as a multifunctional endophytic biocontrol and plant growth-promoting bacterium associated with taro, highlighting their potential as eco-friendly bioinoculants for the sustainable management of taro leaf blight.
Sreekumar Usha Shilpa, M. Jeeva, S. S. Veena et al.· 3 Biotech· 0 citations
Fungal endophytes play a crucial role in plant-microbe interactions by asymptomatically colonizing host tissues, enhancing plant growth, and providing defense. In the present study, three distinct endophytic fungi, namely Fusarium oxysporum CJR-1 (GenBank Accession No. PZ477045), Penicillium sp. CJR-2 (GenBank Accession No. PZ477429) and Aspergillus cf. terreus CJR-4 (GenBank Accession No. PZ477430) were isolated from Crotalaria juncea L. plants and evaluated for antagonistic activity against phytopathogenic fungi and growth promotion in maize. Among the isolates, CJR-4 showed potent antagonistic activity against both tested phytopathogens, inhibiting the mycelial growth of Fusarium oxysporum (ITCC Accession No. 8111) and Alternaria alternata (ITCC Accession No. 1434) by 72.41 ± 5.02% and 68.31 ± 1.53%. On the other hand, isolate CJR-1 showed the highest mycelial inhibition of 74.60 ± 2.06% against A. alternata. Ethyl acetate crude metabolites of CJR-4 exhibited potent antifungal activity, with the highest zone of inhibition observed against A. alternata (21.66 ± 1.52 mm), followed by F. oxysporum (15.33 ± 1.15 mm) at 150 µL of tested concentration. GC-MS analysis of the ethyl acetate extract of CJR-4 revealed numerous bioactive metabolites, including diphenyl sulphone and 2-nonen-1-ol, which may contribute to its antifungal activity. In addition, 1-methylene-1H-indene and ethanone, 2-(formyloxy)-1-phenyl-, may be associated with antioxidant activity, as evidenced by potent DPPH (80.09 ± 0.11%) and ABTS (92.66 ± 0.17%) scavenging activities. Evaluation of PGP traits showed that CJR-1 produced the highest levels of indole-3-acetic acid (IAA) as 305.69 ± 0.41 µg mL⁻1 and ammonia 85.44 ± 0.63 µg mL⁻1, while CJR-2 exhibited the highest phosphate solubilization index (PSI) of 3.09 ± 0.09. Pot experiments conducted under natural light conditions for 28 days demonstrated significantly enhanced plant growth parameters, biomass accumulation, and photosynthetic pigment levels in maize plants inoculated with the CJR-4 isolate. Overall, the findings highlight that endophytic fungi exhibit multifunctional roles and show promise as microbial inoculants for sustainable crop improvement, with CJR-4 emerging as the promising candidate for further development. To the best of our knowledge, this study is among the first to report the isolation and functional characterization of endophytic fungi from Crotalaria juncea L. plant.
Gymnema sylvestre (Gudmar) is an important medicinal plant recognized for its diverse bioactive compounds, including antimicrobial and immune-stimulatory properties, and for its association with beneficial endophytic microorganisms. However, the plant growth-promoting and biocontrol potential of its bacterial endophytes remains poorly understood. The present study aimed to isolate and characterize bacterial endophytes from different tissues of G. sylvestre and evaluate their PGP attributes and antagonistic activity against major soil-borne phytopathogens. A total of 30 bacterial endophytes were isolated from leaf (n = 14), stem (n = 9), and root (n = 7) tissues. Screening for PGP traits revealed that 36.7% of isolates produced indole-3-acetic acid (IAA) (>20 μg/mL), 56.7% produced siderophores, 16.7% solubilized phosphate, and 20.0% solubilized zinc. In addition, 30.0%, 23.3%, 16.7%, and 16.7% of isolates exhibited DNase activity, nitrate reduction, urease production, and citrate utilization, respectively. Extracellular enzyme production was also recorded, with isolates showing amylase (36.7%), protease (30.0%), cellulase (23.3%), and lipase (40.0%) activities. An antagonistic assay against soil-borne fungal pathogens using a dual culture assay showed inhibition of fungal growth in 5, 5, and 3 endophyte isolates against Sclerotium rolfsii, Rhizoctonia solani, and Fusarium oxysporum, respectively with maximum zone of inhibition up to 67%, 67% and 62%, respectively against each pathogen. Based on combined PGP and antagonistic performance, six elite isolates were selected for in-planta validation and molecular identification using 16S rDNA sequencing. In-planta evaluation in chickpea demonstrated significant improvements in seed germination, plant growth, and biomass compared with the uninoculated control. Bacillus cereus strain NIBSM_GdR7 produced the greatest increase in plant height, whereas Bacillus cabrialesii strain NIBSM_GdL7 yielded the highest fresh and dry biomass. Under pathogen challenge, seed biopriming of chickpea with selected endophytes reduced disease incidence caused by S. rolfsii, providing 68.7-87.8% protection, with the highest protection observed for Bacillus proteolyticus strain NIBSM_GdL2. These results indicate that G. sylvestre harbors bacterial endophytes with promising plant growth-promoting and antifungal properties, and that selected Bacillus isolates can in future serve as candidate bioinoculants for sustainable crop improvement and disease suppression.
A. Shrivastava, Lata Jain, Vinay Kumar et al.· Microbial Pathogenesis· 0 citations
Endophytic fungi play an important role in promoting plant growth by producing phytohormones and enhancing nutrient availability; however, their functional roles in orchids remain poorly understood. This study aimed to isolate and functionally characterize plant growth-promoting (PGP) endophytic fungi associated with Vanda tessellata (Roxb.) Hook. ex G.Don. Six representative endophytic fungal isolates were evaluated for plant growth-promoting traits, among which isolate KU/BOT/VT004 exhibited the highest activity. Based on morphological characteristics and ITS rDNA sequence analysis, the isolate was identified as Colletotrichum cf. cobbittiense. The isolate produced high levels of indole-3-acetic acid (35.05 µg/mL), along with ammonia and siderophore activity, indicating strong nutrient-mobilizing potential. Application of the fungal culture filtrate to in vitro-grown protocorms resulted in a two- to three-fold increase in biomass and significantly enhanced chlorophyll content compared with untreated controls. Filtrate-treated protocorms also maintained sustained growth beyond 60 days, whereas nutrient-limited control protocorms exhibited reduced growth. These findings demonstrate the growth-promoting potential of metabolites produced by isolate KU/BOT/VT004 and suggest that this endophytic fungus is a promising candidate for future bioinoculant development and orchid propagation, pending further validation through fungal inoculation and colonization studies.
Findings identify finger millet-associated endophytes, particularly isolate AN6, as promising candidates for the biological management of rice blast disease, and require further greenhouse and field evaluations to confirm their efficacy under natural conditions.
Akhilesh Negi, Aakansha Verma, A. Sharma· Journal of Advances in Biolo...· 0 citations
Overall, this study reports the first isolation of M. circinelloides from Egyptian C. sinuosa and highlights its potential as a promising source of bioactive metabolites with enhanced antibacterial activity and multifunctional properties suitable for pharmaceutical and dermocosmetic applications.
Mostafa M. El-Sheekh, Nessma A El-Zawawy, Ebrahim M. Shalamesh et al.· Scientific Reports· 0 citations
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