Biological and proteomic analysis of a new isolate of the nematophagous fungus lecanicillium sp

Abstract

Background In our continuing search for biologically active natural enemies from North of Africa with special reference to Tunisian fungi, our teamwork screened fungi from different ecological habitats in Tunisia. Our previous study on the comparative effectiveness of filamentous fungi in the biocontrol of Meloidogyne javanica, a taxon (Lecanicillium) showed high potentiality against M. javanica. We undertook the present study to evaluate the ability and understand the mechanism of this fungal parasite as a biological control candidate against the root-knot nematode M. javanica. This study used in vitro bioassays with fungal filtrate cultures, scanning electron microscopy (SEM) observation, and isobaric tag for relative and absolute quantitation (iTRAQ) methodology to characterize the biological and molecular features of this fungus. Results The microscopic and SEM observation revealed that Lecanicillium sp. exhibited exceptional hyperparasitism against M. javanica eggs. The hyphae of this fungi penetrated the eggs, causing destructive damage to the outer eggshell. The exposure to five concentrations of Lecanicillium sp. filtrate cultures showed high inhibition of egg hatching, which increases depending on the exposure time; the best results are recorded at 50%, 75%, and 100% dilutions after seven days of exposure. The SEM observation of nematode-parasitized eggs and juveniles suggests that the production of lytic enzymes degrades the egg cuticle and fungal hyphae penetrate unhatched M.javanica juveniles. Forty-seven unique proteins were identified from the Lecanicillium sp. isolate. These proteins have signalling and stress response functions, bioenergy, metabolism, and protein synthesis and degradation. Conclusion Collectively, Lecanicillium sp. had ovicidal potentiality proved by SEM and proteomic analysis against root-knot nematode’ eggs. This study recommended applying this biological control candidate as a bio-agent on vegetable crops grown in situ.

Verticillium wilt of olive and its control caused by the hemibiotrophic soil-borne fungus Verticillium dahliae

“…have been described as effective biological control agents against a wide range of pathogens, not only through direct action but also through defense system activation. The use of microbial groups (fungi and microorganisms) isolated from the ecological niche of V. dahliae (soil of olive trees) showed significant results against the mycelial growth of V. dahliae and the disease severity (Fernández-González et al, 2020;Hajji-Hedfi et al, 2023b;Hajji-Hedfi et al, 2023c;Matrood et al, 2023). Gómez-Lama Cabanás et al (2018), Castro et al (2020), andZiazia et al (2021) pointed out that Paenibacillus polymyxa, Paenibacillus terrae, Bacillus velezensis, and Pseudomonas putida were highly significant in terms of the growth and germination inhibition rate of V. dahliae (under laboratory conditions), as well as the severity decreasing of Verticillium wilt of olive (under in vivo and field conditions).…”

First Record of Flavocillium subprimulinum (Cordycipitaceae, Hypocreales) in Mexico: Morphological and Molecular Characterisation, Nematocidal Activity of Its Liquid Culture Filtrates against Haemonchus contortus and Protease Activity

“…One of the most widely studied fungal genera belonging to this class is Lecanicillium. Species classified into this genus are potential biocontrol agents with important lethal activity against aphids, scales, whiteflies, thrips, mealy bugs, nematodes, and other insect pests [9][10][11]. Lecanicillium subprimulinum was reported by Huang et al as a novel species from Baoshan, Yunnan, China [12].…”

“…inhibit egg hatching and cause juvenile destruction in M. javanica. This lethal strategy has been attributed to the production of lytic enzymes that act in signaling and stress-response functions, bioenergy, metabolism and protein synthesis, and degradation [10].…”