Genome Sequence of the Biocontrol Agent Coniothyrium minitans Conio (IMI 134523)

Current status and future trends of microbial and nematode-based biopesticides for biocontrol of crop pathogens

The increasing public demand to avoid the use of synthetic pesticides and fertilizers in agricultural production systems, causing serious environmental damages, has challenged industry to develop new and effective solutions to manage and control phytopathogens. Biopesticides, particularly microbial-based biopesticides, are a promising new alternative with high biodegradability, specificity, suitability for incorporation into integrated pest management practices, low likelihood of resistance development, and practically no known human health risks. However: expensive production methods, narrow action spectra, susceptibility to environmental conditions, short shelf life, poor storage stability, legislation registry constraints, and general lack of knowledge are slowing down their adoption. In addition to regulatory framework revisions and improved training initiatives, improved preservation methods, thoughtfully designed formulations, and field test validations are needed to offer new microbial- and nematode-based biopesticides with improved efficacy and increased shelf-life. During the last several years, substantial advancements in biopesticide production have been developed. The novelty part of this review written in 2023 is to summarize (i) mechanisms of action of beneficial microorganisms used to increase crop performance and (ii) successful formulation including commercial products for the biological control of phytopathogens based on microorganisms, nematode and/or metabolites.

Baseline sensitivity and physiological characteristics of natural product hinokitiol against Sclerotinia sclerotiorum

BACKGROUND

Sclerotinia sclerotiorum, a pathogenic fungus of oilseed rape, poses a severe threat to the oilseed rapeseed industry. In this study, we evaluated the potential of the natural compound hinokitiol against S. sclerotiorum by determining its biological activity and physiological characteristics.

RESULTS

Our results showed that hinokitiol strongly inhibited the hyphae expansion of S. sclerotiorum, and its effective concentration of hyphae growing inhibition by 50% (EC50) against 103 S. sclerotiorum strains varied from 0.36 to 3.45 μg/mL, with an average of 1.23 μg/mL. Hinokitiol possessed better protective efficacy than therapeutic effects, and it exhibited no cross-resistance between carbendazim. After treatment with hinokitiol, many vesicular protrusions developed on the mycelium with rough surface and thickened cell wall. Moreover, the cell membrane permeability and glycerol content increased, while the oxalic acid declined after hinokitiol treatment. In addition, hinokitiol induced membrane lipid peroxidation and improved the production of reactive oxygen species (ROS) in S. sclerotiorum. Importantly, real-time quantitative polymerase chain reaction showed that cell wall and ROS synthesis-related genes were significantly up-regulated after hinokitiol treatment.

CONCLUSION

This study revealed that hinokitiol has good biological activity against S. sclerotiorum and could be considered as an alternative bio-fungicide for the resistance management in controlling sclerotinia stem rot infected by S. sclerotiorum. These investigations provided new insights into understanding the toxic action of hinokitiol against pathogenic fungi. © 2024 Society of Chemical Industry.

Potential use of saline resources for biofuel production using halophytes and marine algae: prospects and pitfalls

There exists a global challenge of feeding the growing human population of the world and supplying its energy needs without exhausting global resources. This challenge includes the competition for biomass between food and fuel production. The aim of this paper is to review to what extent the biomass of plants growing under hostile conditions and on marginal lands could ease that competition. Biomass from salt-tolerant algae and halophytes has shown potential for bioenergy production on salt-affected soils. Halophytes and algae could provide a bio-based source for lignoceelusic biomass and fatty acids or an alternative for edible biomass currently produced using fresh water and agricultural lands. The present paper provides an overview of the opportunities and challenges in the development of alternative fuels from halophytes and algae. Halophytes grown on marginal and degraded lands using saline water offer an additional material for commercial-scale biofuel production, especially bioethanol. At the same time, suitable strains of microalgae cultured under saline conditions can be a particularly good source of biodiesel, although the efficiency of their mass-scale biomass production is still a concern in relation to environmental protection. This review summaries the pitfalls and precautions for producing biomass in a way that limits environmental hazards and harms for coastal ecosystems. Some new algal and halophytic species with great potential as sources of bioenergy are highlighted.

Cloning and Molecular Characterization of CmOxdc3 Coding for Oxalate Decarboxylase in the Mycoparasite Coniothyrium minitans

Coniothyrium minitans (Cm) is a mycoparasitic fungus of Sclerotinia sclerotiorum (Ss), the causal agent of Sclerotinia stem rot of oilseed rape. Ss can produce oxalic acid (OA) as a phytotoxin, whereas Cm can degrade OA, thereby nullifying the toxic effect of OA. Two oxalate decarboxylase (OxDC)-coding genes, CmOxdc1 and CmOxdc2, were cloned, and only CmOxdc1 was found to be partially responsible for OA degradation, implying that other OA-degrading genes may exist in Cm. This study cloned a novel OxDC gene (CmOxdc3) in Cm and its OA-degrading function was characterized by disruption and complementation of CmOxdc3. Sequence analysis indicated that, unlike CmOxdc1, CmOxdc3 does not have the signal peptide sequence, implying that CmOxDC3 may have no secretory capability. Quantitative RT-PCR showed that CmOxdc3 was up-regulated in the presence of OA, malonic acid and hydrochloric acid. Deletion of CmOxdc3 resulted in reduced capability to parasitize sclerotia of Ss. The polypeptide (CmOxDC3) encoded by CmOxdc3 was localized in cytoplasm and gathered in vacuoles in response to the extracellular OA. Taken together, our results demonstrated that CmOxdc3 is a novel gene responsible for OA degradation, which may work in a synergistic manner with CmOxdc1.