Antifungal Volatilomes Mediated Defense Mechanism against Fusarium oxysporum f. sp. lycopersici, the Incitant of Tomato Wilt

Volatile Formulation of Mentha spicata Induced Defense Mechanism in Tomato and Suppressed Damping Off Disease Caused by Pythium aphanidermatum

Volatiles produced by the leaves of medicinal plants are increasingly used as a new plant disease management strategy due to their induction of diverse antimicrobial activities, it is highly essential for the development of a new phyto-fumigant product to sustain crop production. The present study attempted to find the active role of Mentha spicata-associated volatile formulation in the suppression of the growth of Pythium aphanidematum under pot culture and field conditions. Damping off disease-causing P. aphanidermatum is a devastating disease that infects the tomato crop from seed sprouting to the seedling stage. To mitigate the damping off incidence, the nature of volatile molecules produced by M. spicata was completely suppressed during di-trophic interaction with P. aphanidermatum. Molecular docking of volatile compound reported carvone as a ligand recorded with the highest binding energy of - 8.5 kcal/mol against the target protein structure of P. aphanidermatum. Application of M. spicata immobilized vermiculite ball in tomato revealed that pathogenesis-related protein (SlPR1) (2.69 folds) and jasmonic acid signaling (SlLOX) (2.65 folds) genes were highly expressed after 48 HPT on tri-trophic interaction of pathogen inoculated tomato plants while the gene SlWRKY and SlTLP exhibited a lower level of gene expression. A significant reduction in the severity of damping off incidence was observed due to the exposure of volatiles of M. spicata in the tomato plant's raised beds with relatively abundant control of P. aphanidematum. This is the first study that attempted to develop the volatile-based formulation and its role in antifungal activities during di-trophic interaction with P. aphanidematum in tomato crops. The present study concludes that the volatiles produced from M. spicata leaves immobilized vermiculite ball could be explored for the management of soil-borne pathogens infecting vegetable crops.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01141-1.

Benzothiazole-An Antifungal Compound Derived from Medicinal Mushroom Ganoderma lucidum against Mango Anthracnose Pathogen Colletotrichum gloeosporioides (Penz and (Sacc.))

The present investigation is focused on exploring the possibilities of identifying biomolecules from the fruiting body of the medicinal mushroom Ganoderma lucidum against the mango anthracnose pathogen Colletotrichum gloeosporioides. The fruiting body (cap and stipe portion) of G. lucidum extracted with ethyl acetate solvent at a maximum inhibitory concentration of 1 percent exhibited the maximum mycelial growth inhibition of C. gloeosporioides with 70.10 percent and 40.77 percent, respectively. Furthermore, subjecting the ethyl acetate extracts from the cap portion of G. lucidum through thin layer chromatography (TLC) revealed the presence of two bands with Rf values of 0.38 and 0.35. The compounds eluted from band 1 recorded with the maximum mycelial growth inhibition of C. gloeosporioides by 53.77 percent followed by band 2 (46.33 percent) using an agar well diffusion test. Similarly, the analysis of ethyl acetate extracts from the cap portion of G. lucidum through Gas Chromatography-Mass spectroscopy (GC-MS) revealed the presence of the organoheterocyclic compound benzothiazole, as expressed in the highest peak area at 22.03 RT with the highest probability percentage (97%). Confirmation of the antifungal nature of benzothiazole was obtained by testing the standard sample of benzothiazole which showed a cent percent of inhibition on mycelial growth of C. gloeosporioides at 50 ppm minimum fungicidal concentration. Furthermore, benzothiazole caused abnormality in the mycelial structures, viz., distortion, shrinkage, clumping of mycelium, conidial malformation, and complete arrestment of conidial germination of C. gloeosporioides as observed through Scanning Electron Microscopy. The research on biomolecular extract of G. lucidum could be a novel and interesting concept for the possibility in suppression of plant pathogenic microbes in the natural field.