Antiviral activity of basidiomycetous fungi against Groundnut bud necrosis virus in tomato

Consortia of Streptomyces spp. triggers defense/PAMP genes during the interaction of Groundnut bud necrosis orthotospovirus in tomato

In the present study, Streptomyces spp. were isolated, characterized, and the efficacy was tested against Groundnut bud necrosis orthotospovirus (GBNV) in tomato. Among the three inoculation methods viz., pre-, post-, and simultaneous inoculation, tested for antiviral efficacy, pre-inoculation spray of the three Streptomyces spp. viz., Streptomyces mutabilis, Streptomyces rochei, and Streptomyces chrestomyceticus (SAT1, SAT4, and STR2) recorded the least disease severity index (DSI) of GBNV in tomato. In the pot culture, seed treatment of liquid consortium of three Streptomyces spp. @ 2 ml/g of seeds along with seedling dip at 10 ml/lit followed by soil drenching at 10 ml/lit on 7 days after transplanting (DAT) and foliar application at 0.5% on 15 DAT, 30 DAT, and 45 DAT recorded the least GBNV infection of 15% DSI and 16.67% DSI in trial I and II respectively. Besides, under field conditions, the disease incidence was reduced to 14.44% recording a higher yield of 76.67 t/ha in the treated plants against 63.99 t/ha in control. Upregulation of defense genes viz., PR1, PR2, PR6, WRKY, MAPKK, and NPR1 during tripartite interaction between tomato, Streptomyces, and GBNV was analyzed by qRTPCR, indicating that the consortia could decrease the virus severity through induced systemic resistance pathways. Thus, it is concluded that Streptomyces spp. can be used for the management of GBNV in tomato.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04030-6.

Emerging challenges in the management of Orthotospoviruses in Indian agriculture

Orthotospoviruses, a genera of negative-sense ssRNA viruses transmitted by thrips, have gained significant attention in recent years due to their detrimental impact on diverse crops, causing substantial economic losses and posing threats to food security. Orthotospoviruses are characterised by a wide range of symptoms in plants, including chlorotic/necrotic spots, vein banding, and fruit deformation. Seven species, including four definite and three tentative species in the genus Orthotospovirus, have so far been documented on the crops of the Indian subcontinent. Management of Orthotospoviruses under field conditions is challenging since they have a wide host range, adaptation to versatile environmental conditions, a lack of promising resistance sources, and the ubiquitous nature of thrips and their transmission through a propagative manner. Our present review elucidates the significance, molecular biology and evolutionary relationship of Orthotospoviruses; vector population; and possible management strategies for Orthotospoviruses and their vectors in the scenario of the Indian subcontinent.

Medicinal Fungi with Antiviral Effect

Pandemics from various viruses make natural organisms face challenges over and over again. Therefore, new antiviral drugs urgently need to be found to solve this problem. However, drug research and development is a very difficult task, and finding new antiviral compounds is desirable. A range of medicinal fungi such as Ganoderma lucidum and Cordyceps sinensis are widely used all over the world, and they can enhance human immunity and direct anti-virus activities and other aspects to play an antiviral role. Medicinal fungi are used as foods or as food supplements. In this review, the species of medicinal fungi with antiviral activity in recent decades and the mechanism of antiviral components were reviewed from the perspectives of human, animal, and plant viruses to provide a comprehensive theory based on better clinical utilization of medicinal fungi as antiviral agents.

Anthelmintic and antimycobacterial activity of fractions and compounds isolated from Cissampelos mucronata

ETHNOPHARMACOLOGICAL RELEVANCE

Cissampelos mucronata A. Rich., a perennial climber belonging to the family Menispermaceae, has been used traditionally to treat parasites and tuberculosis-related symptoms. Co-infection of helminth parasites and tuberculosis-causing pathogens heightens the risk of developing active tuberculosis.

AIM OF THE STUDY

The aim was to isolate and characterize antimycobacterial compounds from Cissampelos mucronata and to investigate their antibiofilm and anthelmintic efficacy as well as cytotoxicity.

MATERIALS AND METHODS

The acetone extract of C. mucronata leaves and stems was fractionated by vacuum liquid chromatography using hexane, ethyl acetate, acetone and methanol:chloroform (3:7). Separation of the active ethyl acetate fraction by column and preparative thin layer chromatography led to the isolation and identification of five compounds using NMR and LC-MS, as well as GC-MS for non-polar compounds. The anthelmintic, antimycobacterial, antibiofilm, antioxidant and anti-inflammatory effects as well as cytotoxicity of the fractions and compounds were determined.

RESULTS

The ethyl acetate fraction had the best antimycobacterial activity (MIC = 0.015-0.08 mg/ml). The fractions were relatively non-toxic to Vero cells (0.03-0.79 mg/ml) and had good anti-inflammatory and antibiofilm effects. Five compounds were identified as stigmasterol, hentriacontane, simiarenol, nonacosene and carbonic acid. Nonacosene had moderate anthelmintic effects but poor antimycobacterial activity (MIC = 0.375 mg/ml). Nonacosene and hentriacontane had good biofilm inhibitory effect (90-100%).

CONCLUSIONS

This study reveals that C. mucronata is a potential source of promising compounds with a range of useful bioactivities that support its use in traditional medicine. Development of plant-based remedies may assist in reducing the impact of co-infections with helminth parasites and tuberculosis-causing mycobacteria.

Molecular modelling of coat protein of the Groundnut bud necrosis tospovirus and its binding with Squalene as an antiviral agent: In vitro and in silico docking investigations

Bud blight disease caused by groundnut bud necrosis virus (GBNV) is a serious constraint in the cultivation of agricultural crops such as legumes, tomato, chilies, potato, cotton etc. Owing to the significant damage caused by GBNV, an attempt was made to identify suitable organic antiviral agents through molecular modelling of the nucleocapsid Coat Protein of GBNV; molecular docking and molecular dynamics that disclosed the interaction of the ligands viz., Squalene and Ganoderic acid-A with coat protein of GBNV. Invitro inhibitory effect of Squalene and Ganoderic acid-A was examined in comparison with different concentrations, against GBNV in cowpea plants under glasshouse condition. The different concentrations of Squalene (50, 100, 150, 250 and 500 ppm) tested in vitro resulted in reduction of lesion numbers (1.69 cm²) as well as reduced virus titre in co-inoculation spray. The present study suggests the antiviral activity of Squalene by effectively fitting into binding site of coat protein of GBNV with favourable hydrophilic as well as strong hydrophobic interactions thereby challenging and blocking the binding of viral replication RNA with coat protein and propagation. The present organic antiviral molecules will be helpful in development of suitable eco-friendly formulations to mitigate GBNV infection disease in plants.