Identification, Characterization, and Evaluation of Nematophagous Fungal Species of Arthrobotrys and Tolypocladium for the Management of Meloidogyne incognita

Abstract

Root-knot nematodes belonging to the genus Meloidogyne are agriculturally important pests, and biocontrol strategies offer safer alternatives for their management. In the present study, two fungal species from Indian soils were identified as Arthrobotrys thaumasia and Tolypocladium cylindrosporum based on morphological characteristics and further confirmed using molecular markers. In vitro evaluation of A. thaumasia against M. incognita and Caenorhabditis elegans showed 82 and 73% parasitism, respectively, whereas T. cylindrosporum gave 65.2 and 57.7% parasitism, respectively. Similarly, culture filtrates of A. thaumasia caused 57.7 and 53.7% mortality of M. incognita and C. elegans, respectively, whereas T. cylindrosporum caused higher mortality of 87.3 and 64%, respectively. Besides, greenhouse evaluation of both fungi against M. incognita infecting tomato significantly reduced nematode disease burden reflecting parasitic success measured as the total number of galls, egg masses, eggs per egg mass, and derived nematode multiplication factor. Application of A. thaumasia and T. cylindrosporum reduced nematode multiplication factor by 80 and 95%, respectively, compared with control. General metabolite profiling of tested fungi using gas chromatography–mass spectrometry and ultra-performance liquid chromatography–quadrupole/time of flight mass spectrometry reported for the first time here showed presence of various volatile and non-volatile compounds with nematicidal activity, viz., trimethyl-heptadiene, methyl-hexadecanol, dodecadienal, decane, terpendole E, dodecane, acetamido-6-anthraquinone, and hexadecanol. Also, other compounds such as undecane, dibutyl-disulfide, octadecenal, paganin, talathermophilin, dactylarin, tolypyridone A, tolypyridone B, pyridoxatin, and destruxin were identified, reported in the literature to possess antibacterial, antifungal, and insecticidal properties. This is the first report of the occurrence of both fungi from India and pioneer demonstration of T. cylindrosporum for root-knot nematode management.

Biosynthesis of Cry5B-Loaded Sulfur Nanoparticles using Arthrobotrys oligospora Filtrate: Effects on Nematicidal Activity, Thermal Stability, and Pathogenicity against Caenorhabditis elegans

“…incognita and C. elegans . In this study, however, we were unable to observe nematicidal activity when the A.…”

“…29 In addition, pyrazine, one of the volatile organic compounds identified in the fungal filtrate of A. oligospora, was among the metabolites identified in the fungal filtrate of A. thaumasia that could be responsible for its nematicidal activity against M. incognita and C. elegans. 30 In this study, however, we were unable to observe nematicidal activity when the A. oligospora fungal filtrate was applied to C. elegans (data not shown), implying that the concentrations of VOCs present in the A. oligospora fungal filtrate were insufficient to exert nematicidal activity. Nonetheless, it remained to be determined whether the sulfur nanoparticles mediated by the fungal filtrate of A. oligospora (AO-SNPs) could contribute to the nematicidal activity.…”

Unearthing diverse culturable fungal communities associated with Ophiocordyceps indica sp. nov. from Indian Western Himalaya

“…The isolated associated entomopathogenic and plant growth promoting fungi can be utilized in boosting the agriculture sector in terms of bio-pesticides and biofertilizers development [23][24][25][26]. Keeping in view the pesticidal potential of the entomopathogenic fungi associated with O. indica, one of the identified fungus B. bassiana showed promising activities against insect (Aphids, Aphis craccivora; Diamondback moth, Plutella xylostella and twospotted spider mite, Tetranychus urticae) pests (Unpublished data).…”

Rice leaf endophytic Microbacterium testaceum: Antifungal actinobacterium confers immunocompetence against rice blast disease

“…9-Octadecenoic acid (Oleic acid) has been the most abundant anti-bacterial unsaturated fatty acid naturally found in staphylococcal abscesses as well as on the skin surface (Speert et al, 1979;Dye and Kapral, 1981). The antimicrobial nature of other chemicals observed in M. testaceum D18 has been reported in the recent past; Tetradecanoic acid (Gajbhiye and Kapadnis, 2021;Nakkeeran et al, 2020), Propenoic acid butyl ester (Garnier et al, 2020), 2-Hexanone (Rocha et al, 2004), Trimethyl-heptadien-4-one (Kassam et al, 2021), 4-Dimethyl-1-heptene (Mannaa and Kim, 2018), 4-Methyl-2-pentanol (Petrović et al, 2013), and 3-Hexanone (Wang et al, 2020).…”