Activity of volatiles induced by microbes and natural plants stifled the growth of Pythium aphanidermatum - the damping off in Tomato.

BACKGROUND: Volatilomes from natural plants and microbes imparts diverse antifungal properties to suppress the growth of plant pathogens and therefore can be a suitable alternative of chemical fungicides. The present experiment was to study effect of volatiles produced by natural plants and microbes on the fungal growth of Pythium aphanidermatum, which is a tomato seedling pathogen. RESULTS: Isolate of P. aphanidermatum, causing damping off in tomato were isolated and incubated at 25 ± 2 °C. The isolate was tested for the anti-oomycetes activities of volatiles in vitro. The volatiles produced by the leaves of Mentha spicata and Cymbopogon citratus showed the maximum inhibitory effect of 45.56 and 24.70 percent, respectively on the mycelial growth of P. aphanidermatum, whereas, the pathogen was not inhibited on exposure to the volatiles of macro-basidiomycetes fungi. The volatiles of T. asperellum showed the maximum inhibitory effect of 69.26 percent against P. aphanidermatum. The study also included the identification of Volatile Organic Compounds (VOCs) involved in the suppression of pathogens by Headspace Gas Chromatography Mass Spectrometry (HS GCMS). The results revealed the production of carvone by the leaves of M. spicata; citronellol and geraniol by C. citratus; isopentyl alcohol and limonene by T. asperellum with increased peak area percentage and these compounds possessed antifungal properties. The vaporous action of isopentyl alcohol completely suppressed the mycelial growth of P. aphanidermatum, which is highly correlated to the T. asperellum extract on pathogenic growth. While the compounds, carvone, and citronellol showed the maximum inhibitory effect of 89.02 and 85.49 percent, respectively when used at 500 ppm and also altered the sporulation behavior of P. aphanidermatum. CONCLUSION: Results showed that volatiles of M. spicata and T. asperellum have anti-oomycetes action on pathogenic growth leading to a distortion of sporulation of P. aphanidermatum. High antifungal properties make VOCs suitable for incorporation as a new integrated plant disease management programs.

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.

Differential bacterial endophytome in Foc-resistant banana cultivar displays enhanced antagonistic activity against Fusarium oxysporum f.sp. cubense (Foc).

Diverse endophytes with multiple functions exist in different banana cultivars. However, the diversity of cultivable bacterial endophytome that contributes to antifungal activity against Fusarium oxysporum f.sp. cubense (Foc) in resistant and susceptible banana cultivars is mostly unknown. In the present study, we isolated bacterial endophytes from resistant Yengambi KM5 (AAA) and susceptible banana cultivar Ney Poovan (AB) to determine the diversity of cultivable bacterial endophytes. Our study revealed the presence of 56 cultivable bacterial endophytes and 6 nectar-associated bacteria in YKM5 and 31 cultivable bacterial endophytes in Ney Poovan. The identified cultivable bacterial genera in YKM5 included Alcaligenes, Arthrobacter, Azotobacter, Acinetobacter, Agrobacterium, Bacillus, Brucella, Brevundimonas, Brachybacterium, Beijerinckia, Klebsiella, Leclercia, Lysinibacillus, Myroides, Ochrobactrum, Pseudomonas, Rhizobium, Stenotrophomonas, Serratia, and Verticiella. In Ney Poovan, the cultivable endophytic bacterial genera present were Agrobacterium, Bacillus, Bradyrhizobium, Enterobacter, Klebsiella, Lysinibacillus, Micrococcus, Ochrobactrum, Pseudomonas, Rhizobium, and Sphingobium. Thus, the composition and diversity of cultivable endophytic bacterial genera were higher in Foc-resistant YKM5. The antifungal efficacy of bacterial endophytes Brachybacterium paraconglomeratum YEBPT2 (65.5%), Brucella melitensis YEBPS3 (63.3%), Bacillus velezensis YEBBR6 (63.3%), and nectar-associated Bacillus albus YEBN2 (61.1%) from YKM5 showed the highest antifungal activity against Foc, compared with the antifungal activity of endophytes from the susceptible cultivar.

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

In this study, the volatilomes of naturally growing plant leaves were immobilized in a suitable substrate to enhance vapors' diffusion in the soil to eradicate the Fusarium wilt pathogens in Tomato. Volatilomes produced by Mentha spicata leaves immobilized in vermiculite ball was found to be effective and exhibit 92.35 percent inhibition on the mycelial growth of Fusarium oxysporum f. sp. lycopersici (FOL). Moreover, the volatilomes of M. spicata immobilized vermiculite balls were tested based on the distance traveled by the diffused volatilomes from the ball and revealed that the volatilomes of M. spicata traveled up to 20 cm distance from the center of PVC (Polyvinly chloride) chamber showed maximum reduction in colony growth of FOL at 12th day after inoculation. Tomato plants inoculated with FOL revealed increased expressions of defense gene, pathogenesis related protein (PR1) with 2.63-fold after 72 h and the gene, transcription factor (WRKY) increased with 2.5-fold after 48 h on exposure to the volatilomes of M. spicata vermiculite balls. To the best of our knowledge, this is the first report on development of volatilomes based vermiculite ball formulations. This result indicated that the volatilomes of M. spicata are promising phyto-fumigants for management of Tomato Fusarial wilt.

Differential Modulation in Metabolites Revealed with the Improvement in the Shelf-Life of Alphonso Fruits.

Globally farmers have difficulty in extending the shelf-life of the tropical fruits due to their perishable nature. The present study aimed to assess the effect of hexanal nano-formulation treatment (NFT) on the shelf-life of Alphonso mango. Further, volatilomics was performed to explore the molecular basis of such effect. Untreated and treated fruits were sampled starting from 5th to 21st day after NFT at an interval of 4 days. Moderate changes in visual and digital colour parameters were evident from the intact and dissected fruits of NFT set compared to untreated fruits. Biochemical assays affirmed the phenotypic differences with significant changes in the colour imparting compounds like carotenoids and anthocyanins among them. Further, gas chromatography-mass spectrometry analysis revealed significant qualitative and quantitative variations in the different classes of compounds like lactones, furanones, esters, aldehydes and alcohols. Some of the key metabolites showed differential modulations among the NFT and untreated fruit sets indicating their potential role in various processes, which ultimately might have resulted in delayed ripening of the mango. Overall, this study has demonstrated the beneficial effect of hexanal and identified important metabolites with the enhanced shelf-life in Alphonso that could be useful for farmers and mango-based food/flavour industries.

Osteogenic stimulatory effect of heraclenin purified from bael in mouse mesenchymal stem cells in vitro.

Osteoporosis is a major health concern occurring to the aging adult population across the globe. Currently, there is an increasing demand for treatment of osteoporosis with plant-based medicines. In the present study, we report that heraclenin was extracted and purified from unripe fruit portion of Bael (Aegle marmelos Corr.) using silica gel column chromatography. The identification and characterization of heraclenin were carried out by UV-Vis, HPLC, LC-MS, NMR, FT-IR, and XRD analyses. The standardized purification method recorded a yield efficiency of 42% heraclenin microcrystals with 99% purity from bael fruit. SEM image revealed the shape of the purified compound to be an orthorhombic-sphenoid prism. Cytotoxicity studies indicated that heraclenin-treatment did not alter cell viability in mouse mesenchymal stem cells (mMSCs, C3H10T1/2). The mRNA expression of Runx2, a bone transcription factor was found to be stimulated by heraclenin in these cells. At the cellular level, heraclenin-treatment enhanced osteoblast differentiation and mineralization in mMSCs. Thus, these results suggested that heraclenin purified from bael fruit has an osteogenic effect, indicating its potential towards bone regeneration.