Discovery of succinate dehydrogenase candidate fungicides via lead optimization for effective resistance management of Fusarium oxysporum f. sp. capsici.

Fusarium wilt of chili caused by the fungus Fusarium oxysporum f. sp. capsici (FCO) severely reduces the production of chili worldwide. There is growing evidence of resistance to commercial fungicides targeting succinate dehydrogenase (Sdh) of FCO soliciting the development of new Sdh inhibitors (SdhIs). In the current work, optimized docking and virtual screening were used to mine twelve SdhIs from the ZINC database, followed by in vitro antifungal evaluation on spore and radial mycelium development. Four new promising SdhIs exhibiting a mean mycelium inhibition rate greater than 85.6% (F = 155.8, P = 0.001, P < 0.05) were observed on ten strains of virulent and resistant FCO. Importantly, three of the discovered molecules exhibited potent spore germination inhibition (≥ 80%, P = 0.01, P < 0.05) compared to the commonly used fungicide penthiopyrad. A significant positive correlation (r* ≥ 0.67, P < 0.05) between the activities of the newly discovered SdhIs compared to penthiopyrad against all tested FCO strains indicated a broad-spectrum fungicidal activity. The current findings indicate that the four SdhI's discovered could judiciously replace certain commercial SdhIs that some FCO displays resistance to. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03157-8.

Expression of ice recrystallization inhibition protein in transgenic potato lines associated with reduced electrolyte leakage and efficient recovery post freezing injury.

Potato (Solanum tuberosum L.) is considered to be frost-susceptible as short spells of frost can reduce the tuber yield and quality. Ice recrystallization inhibition (IRI) protein helps prevent growth of ice crystals in the cell apoplast during frost and help prevent damage associated with freezing stress. In this study, we investigated the in planta potential of Lolium perenne derived IRI3 transgene in improving the tolerance of transgenic potato lines for freezing stress. The codon optimized IRI3 transgene was introduced into potato cultivar Diamant through Agrobacterium mediated transformation. Three transgenic potato lines were successfully generated which were confirmed for transgene insertion and genomic integration by polymerase chain reaction and Southern blot. It was evident that the IRI3 transcript decreased in initial 24 h of cold stress treatment while the IRI3 mRNA expression up regulated in subsequent hours of cold treatment with maximum increase to 20 folds at 96 h post stress. A similar trend was also revealed in ion-leakage assay which showed that during cold stress, the transgenic potato lines depicted reduced ion leakage of 14-22% as compared to non-transgenic control plants. Further, the generated transgenic potato lines were tolerant to the frost spell in quarantine field conditions as compared to the non-transgenic potato lines. Additionally, the transgenic lines exhibited efficient recovery post frost injury in field conditions. The biochemical profiles of chlorophyll, proline and higher levels of antioxidant enzyme (superoxide dismutase, Catalase) activity and malondialdehyde levels showed that despite the phenotypic impact of low temperature, the transgenic potato lines quickly adjusted to maintain their cellular homeostasis post freezing stress by increasing the antioxidant defenses. This study suggests that up regulation of IRI3 transcript and regulatory network of cold stress response in transgenic potato lines improve frost tolerance and help stabilize yield in cultivated potato.

Biotechnological application of endophytic filamentous bipolaris and curvularia: a review on bioeconomy impact.

The filamentous Bipolaris and Curvularia genera consist of species known to cause severe diseases in plants and animals amounting to an estimated annual loss of USD $10 billion worldwide. Despite the harmful effect of Bipolaris and Curvularia species, scarce attention is paid on beneficial areas where the fungi are used in industrial processes to generate biotechnological products. Catalytic potential of Bipolaris and Curvularia species in the production of biodiesel, bioflucculant, biosorbent, and mycoherbicide are promising for the bioeconomy. It is herein demonstrated that knowledge-based application of some endophytic Bipolaris and Curvularia species are indispensable vectors of sustainable economic development. In the twenty-first century, India, China, and the USA have taken progress in the biotechnological application of these fungi to generate wealth. As such, some Bipolaris and Curvularia species significantly impact on global crop improvement, act as catalyst in batch-reactors for biosynthesis of industrial enzymes and medicines, bioengineer of green-nanoparticle, agent of biofertilizer, bioremediation and bio-hydrometallurgy. For the first time, this study discusses the current advances in biotechnological application of Bipolaris and Curvularia species and provide new insights into the prospects of optimizing their bioengineering potential for developing bioeconomy.

Invasive Aspergillus terreus morphological transitions and immunoadaptations mediating antifungal resistance.

BACKGROUND AND AIMS: Aspergillus terreus Thom is a pathogen of public health and agricultural importance for its seamless abilities to expand its ecological niche. The aim of this study was holistically to investigate A. terreus morphological and immunoadaptations and their implication in antifungal resistance and proliferation during infection. MATERIALS AND METHODS: In-depth unstructured mining of relevant peer-reviewed literature was performed for A. terreus morphological, immune, resistance, and genetic diversity based on the sequenced calmodulin-like gene. RESULTS: Accessory conidia and phialidic conidia produced by A. terreus confer discrete anti-fungal resistance that ensures survivability during therapies. Interestingly, by producing unique metabolites such as Asp-melanin and terretonin, A. terreus is capable of hijacking macrophages and scavenging iron, respectively. As such, A. terreus has established a rare mechanism to mitigate phagocytosis and swing the interaction dynamics in favor of its proliferation and survival in hosts. CONCLUSION: It is further unraveled that besides A. terreus genetic diversity, morphological, biochemical, and immunologic adaptations associated with conidia germination and discharge of chemical signals during infection enable masking of the host defense as an integral part of its strategy to survive and rapidly colonize hosts.