Arbuscular mycorrhizal fungi alter antifungal potential of lemongrass essential oil against Fusarium solani, causing root rot in common bean (Phaseolus vulgaris L.)

Abstract

The variation in chemical composition of essential oils (EOs) as affected by plant phenology and environmental factors is a crucial limitation in standardization of EOs and thus their effective implementation into novel organic farming. The cultivation of medicinal and aromatic plants (MAP) using bio-elicitors has been advocated as genuine tool to sustainably assure higher quantity and quality EOs. Herein, a field trial and laboratory bioassays were undergone to decipher the impact of a local arbuscular mycorrhizal fungi (AMF) inoculation on agro-morphological yield, EO output and differential suppression of common bean ( Phaseolus vulgaris L.) root rot incited by Fusarium solani. The field experiment was laid out following a completely randomized block design (CRBD) with two treatments; non-inoculated control and AMF-inoculation in triplicates. The effects of the EOs were tested against mycelial growth, conidia and common bean seeds germination. Promising concentrations were thereafter assessed for their suppressive effect against Fusariun solani in planta . A significantly higher collar diameter, hypocotyl branching and subsequent Mycorrhizal Dependency (MD) in mycorrhizal lemongrass [(+)AMF] compared to non-inoculated counterpart [(-)AMF]. The resulting EOs consistently repressed F. solani Fs4 conidia germination and mycelium deployment in a dose-dependent manner, with minimum inhibitory concentration (MIC) of 500 ppm for both the EOs, and 125 ppm for the reference fungicide (Ridomil Plus 44 WP). The EO from mycorrhizal lemongrass protected the common bean plantlets from infection by F. solani Fs4 both in laboratory and greenhouse conditions, leading to healthier and vigorous plantlets. The best protection rate was once more obtained with EO from AMF-primed lemongrass at the concentration of 1000 ppm (65.0%) while the lowest disease severity was obtained with Ridomil Plus 44 WP (63.13%). Overall, AMF inoculation shifted the lemongrass biochemical processes with subsequent impact on growth, and an enhanced suppression in Fusarium root rot under greenhouse conditions.

Evaluation of the ef fect of native arbuscular mycorrhizal fungi an vermicompost leachate on the yield and quality of f ield-grown peanuts

“…The results demonstrate the benef icial ef fect of the interaction between AMF and leachate against pathogenic fungi such as Cercospora personata, in this sense, Eke et al (2020) corroborate that AMF inoculation changed the biochemical processes of the bean plant (Phaseolus vulgaris L.) with a subsequent impact on growth and greater suppression of root rot by Fusarium under greenhouse conditions.…”

Roles of Arbuscular mycorrhizal Fungi as a Biocontrol Agent in the Control of Plant Diseases

“…Compared with the control without AMF inoculation, the disease index and incidence of Ralstonia solanacearum inoculated with G. rhizogenes and G. mossie were reduced by 9.7% and 49.8%, respectively [ 23 ]. G. asciculatum , G. etunicatum , G. macrocarpum , G. Margarita , G. heterogama, and G. calospora in AMF can reduce the diseases caused by pathogenic fungi of the genera Pythium , Phytophthora , Fusarium , Rhizoctonia , Macrophomina , Pyrenochaeta , Thielaviopsis , Phoma , Cylindrocarpum , Ophiobolus , and Sclerotium in barley, peanut, soybean, banana, cotton, kidney bean, onion, tobacco, citrus, peach, poplar, strawberries, red clover, and ginseng [ 24 , 25 , 26 , 27 , 28 , 29 ]. Sudhasha et al [ 30 ] found that G. intraradices inhibited the growth of the pathogenic fungus F. oxysporum and proposed that the chemical balance of mycorrhizae inhibited the growth and reproduction of pathogenic fungi.…”

Evaluation of in-vitro antifungal activity against Fusarium incarnatum of binary and ternary combinations of lemongrass, garlic and mustard oil-encapsulated lipid nanoemulsions

“…First, the concentration of each constituent EO of the ternary formu-lation at 600 times dilution was only 0.0556 g/L, while that of the binary formulation was 0.0833 (approximately 1.5 times higher). Secondly, at this dilution, the low concentration (0.0556 g/L) of lemongrass oil, garlic oil and mustard oil contained in the ternary formulation might be lower than the minimal inhibitory concentration (MIC) needed to effectively inhibit the growth of F. incarnatum (Dutta et al, 2021;Eke et al, 2020;Wang et al, 2020). Particularly, MIC for controlling Fusarium solani of lemongrass oil was 0.5 g/L (Eke et al, 2020), while MIC against Fusarium oxysporum f. sp.…”