Sclerotinia sclerotiorum causes white mold disease, resulting in losses of up to 50% in several host plants worldwide. It is a harmful fungus as it infects plants at any stage of development, in the field, or in storage; this includes young seedlings, mature plants, and fruits. The accessibility of molecular and biological methods has contributed significantly to our understanding of S. sclerotiorum etiology and progression. The present research aimed to characterize S. sclerotiorum causing white mold disease in eggplant (S. melobgena), evaluate the potentiality of some bio-agents for inhibiting the fungus growth and develop a strategy for dealing with the disease challenge. Eggplants grown in open fields and greenhouses showed cottony growth on their stems, followed by the emergence of sclerotia. A fungal growth with fluffy mycelium and considerable sclerotia was isolated from the infected tissues. Polyphasic characterization and phytopathological analysis identified the fungus as S. sclerotiorum. The symptoms previously seen in the field were reproduced by inoculating healthy eggplant roots, stems, and leaves with the fungus. The ITS rDNA sequencing (564 bp) homology and phylogenetic analysis showed 99% sequence similarity of the isolate with multiple S. sclerotiorum. A wide range of strategies are required for disease management. S. sclerotiorum is sensitive to competition from other bacteria. Such a technique might act as an initial basis for effective biological control of white mold. The results demonstrated that eight isolates have very strong antagonistic activity against S. sclerotiorum. Reduced rates ranged from 63.1% (65 D) to 39.0.1% (75 A1). At the same time, the effect of the Trichoderma harzianum fungus against the pathogen S. sclerotium was apparent in restricting mycelium growth and inhibiting the fungus growth. ITS sequencing identified the mycopathogen. The interaction of seven Bacillus spp isolates with S. sclerotiorum on PDA culture media highlighted these isolates' capacity to limit the pathogen's mycelial growth. Furthermore, the antimicrobial agent must remain in the same environment for an extended period while also being active against the pathogen.

This research evaluated the biocontrol potential of the bacterial flora from cured sugarcane bagasse (SCB) against Fusarium oxysporum f. sp. lycopersici (Fol), the causal agent of tomato Fusarium wilt. Screenings of twenty SCB-derived isolates revealed consistent antagonistic activity, inhibiting mycelial growth from 32.08% to 55.00%. The most effective isolate, 100MTN1, was identified via 16S rRNA sequencing (GenBank: PX506225) as Bacillus atrophaeus. Interaction between B. atrophaeus 100MTN1 and Fol FOLViF has revealed a distinct profile of bioactive metabolites produced specifically during co-cultivation. Transcriptomic profiling of Fol FOLViF exposure to 100MTN1 identified 189 differentially expressed genes, with downregulation of genes involved in DNA replication, translation, and membrane transport, and upregulation of those linked to secondary metabolism and oxidative stress. KEGG pathway mapping further supported the possible causes of disruptions within the pathogen. Molecular docking suggested that the B. atrophaeus 100MTN1 derived metabolite, 6-Hydroxy-3′-methoxyflavone and exhibits binding affinity for key Fol proteins that compares favorably with the commercial fungicides. Greenhouse trials using tomato cv. Kalyan confirmed that treatment with strain 100MTN1 was associated with reduced disease severity and enhanced plant growth. These findings suggest that B. atrophaeus 100MTN1 suppresses Fol FOLViF through a combination of metabolite-driven inhibition and transcriptional interference, signifying its potential as a biological control agent for managing Fusarium wilt.

A survey in 2016 showed that more than 80% lebbeck trees inside the main campus of Qassim University were wilted and dead. Symptoms of dieback, root rot, stem cankers and decline were observed in the trees. The trunks exhibited black masses of spores which soon spread to other, healthy trees. A fungus, having arthroconidial and asexual synanamorph characteristics, and was identified as Neoscytalidiumdimidiatum KSA of the class Coelomycetes within the family Botryosphaeraceae and was subsequently isolated from the infected lebbeck trees. Six-year-old lebbeck seedlings were inoculated with the N. dimidiatum KSA isolate. Symptoms of chloroses followed by dropping leaves appeared four weeks after inoculation. The fungus re-isolated from the infected seedlings expressed the same morphological characteristics on the culture media as the N. dimidiatum KSA isolate. A host range study involving six different tree species were inoculated under growth chamber conditions using the identified isolate of the N. dimidiatum KSA fungus. Four weeks after the inoculation, three of these species exhibited wilting and died. To the best of our knowledge, this study is the first to report on N. dimidiatum in Saudi Arabia.