The Role of Saccharides in the Mechanisms of Pathogenicity of Fusarium oxysporum f. sp. lupini in Yellow Lupine (Lupinus luteus L.)

Fusarium Wilt Invasion Results in a Strong Impact on Strawberry Microbiomes

Plant-endophytic microbes affect plant growth, development, nutrition, and resistance to pathogens. However, how endophytic microbial communities change in different strawberry plant compartments after Fusarium pathogen infection has remained elusive. In this study, 16S and internal transcribed spacer rRNA amplicon sequencing were used to systematically investigate changes in the bacterial and fungal diversity and composition in the endophytic compartments (roots, stems, and leaves) of healthy strawberries and strawberries with Fusarium wilt, respectively. The analysis of the diversity, structure, and composition of the bacterial and fungal communities revealed a strong effect of pathogen invasion on the endophytic communities. The bacterial and fungal community diversity was lower in the Fusarium-infected endophytic compartments than in the healthy samples. The relative abundance of certain bacterial and fungal genera also changed after Fusarium wilt infection. The relative abundance of the beneficial bacterial genera Bacillus, Bradyrhizobium, Methylophilus, Sphingobium, Lactobacillus, and Streptomyces, as well as fungal genera Acremonium, Penicillium, Talaromyces, and Trichoderma, were higher in the healthy samples than in the Fusarium wilt samples. The relative abundance of Fusarium in the infected samples was significantly higher than that in the healthy samples, consistent with the field observations and culture isolation results for strawberry wilt. Our findings provide a theoretical basis for the isolation, identification, and control of strawberry wilt disease.

Untargeted 1 H-NMR Metabolome of Celery During Fusarium Wilt: Implications for Vegetable Quality

Celery is a vegetable widely consumed as a condiment to prepare diverse dishes around the world. Nevertheless, this plant is susceptible to the attack of several phytopathogens including those of the Fusarium genus which is translated into devastating losses for the production chain. Herein we report on the metabolic changes produced during the celery wilt caused by Fusarium oxysporum which was determined through untargeted ¹ H-NMR metabolomics. The changes in the metabolite content of celery were measured at 16, 24, and 32 days post-inoculation using viable conidia obtained from the native F. oxysporum strain FO3. Our results demonstrated that the parasitic activity of the fungus reduced the endogenous levels of free sugars (fructose, galactose, glucose isomers, mannose, Myo-inositol, mannitol, and sucrose) amino acids (alanine, aspartate GABA, glutamate, glutamine, histidine, isoleucine, leucine, methionine, proline, threonine, tyrosine, and valine), nucleosides (adenosine, cytidine, guanosine, and uridine) and organic acids (citric acid, fumaric acid, malic acid, and succinic acid). Interestingly, the levels of tyrosine and tryptophan were triggered as a consequence of F. oxysporum infection. This tendency was correlated with an increase in the levels of chlorogenic acid, apiin, and apigenin derivatives, suggesting their involvement in the chemical defense of celery against fungal colonization. According to principal component analysis (PCA) and Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) methanol was the main differential metabolite and it was considered as a new chemical marker associated with F. oxysporum infection. Our results demonstrate that infected celery plants dramatically reduced their nutritional and nutraceutical contents during Fusarium wilt after 32 days post-inoculation. However, these findings also suggest that the phenylpropanoid pathway is strongly related with the chemical defense of celery against F. oxysporum.

Potential inhibitory activity of phytoconstituents against black fungus: In silico ADMET, molecular docking and MD simulation studies

Mucormycosis or “black fungus” has been currently observed in India, as a secondary infection in COVID-19 infected patients in the post-COVID-stage. Fungus is an uncommon opportunistic infection that affects people who have a weak immune system. In this study, 158 antifungal phytochemicals were screened using molecular docking against glucoamylase enzyme of Rhizopus oryzae to identify potential inhibitors. The docking scores of the selected phytochemicals were compared with Isomaltotriose as a positive control. Most of the compounds showed lower binding energy values than Isomaltotriose (-6.4 kcal/mol). Computational studies also revealed the strongest binding affinity of the screened phytochemicals was Dioscin (-9.4 kcal/mol). Furthermore, the binding interactions of the top ten potential phytochemicals were elucidated and further analyzed. In-silico ADME and toxicity prediction were also evaluated using SwissADME and admetSAR online servers. Compounds Piscisoflavone C, 8-O-methylaverufin and Punicalagin exhibited positive results with the Lipinski filter and drug-likeness and showed mild to moderate of toxicity. Molecular dynamics (MD) simulation (at 300 K for 100 ns) was also employed to the docked ligand-target complex to explore the stability of ligand-target complex, improve docking results, and analyze the molecular mechanisms of protein-target interactions.

The Role of Sugars in Plant Responses to Stress and Their Regulatory Function during Development

Due to their role as energy and carbon sources and their regulatory functions, sugars influence all phases of the plant life cycle, interact with other signaling molecules, including phytohormones, and control plant growth and development [...].

Endophytic Bacillus subtilis TR21 Improves Banana Plant Resistance to Fusarium oxysporum f. sp. cubense and Promotes Root Growth by Upregulating the Jasmonate and Brassinosteroid Biosynthesis Pathways

The banana (Musa spp.) industry experiences dramatic annual losses from Fusarium wilt of banana disease, which is caused by the fungus Fusarium oxysporum f. sp. cubense (FOC). Pisang Awak banana 'Fenza No. 1' (Musa spp. cultivar Fenza No. 1), a major banana cultivar with high resistance to F. oxysporum f. sp. cubense race 4, is considered to be ideal for growth in problematic areas. However, 'Fenza No. 1' is still affected by F. oxysporum f. sp. cubense race 1 in the field. TR21 is an endophytic Bacillus subtilis strain isolated from orchids (Dendrobium sp.). Axillary spraying of banana plants with TR21 controls Fusarium wilt of banana, decreasing the growth period and increasing yields in the field. In this study, we established that TR21 increases root growth in different monocotyledonous plant species. By axillary inoculation, TR21 induced a similar transcriptomic change as that induced by F. oxysporum f. sp. cubense race 1 but also upregulated the biosynthetic pathways for the phytohormones brassinosteroid and jasmonic acid in 'Fenza No. 1' root tissues, indicating that TR21 increases Fusarium wilt of banana resistance, shortens growth period, and increases yield of banana by inducing specific transcriptional reprogramming and modulating phytohormone levels. These findings will contribute to the identification of candidate genes related to plant resistance against fungi in a nonmodel system and facilitate further study and exploitation of endophytic biocontrol agents.

Physiological and Biochemical Response to Fusarium culmorum Infection in Three Durum Wheat Genotypes at Seedling and Full Anthesis Stage

Fusarium culmorum is a worldwide, soil-borne plant pathogen. It causes diseases of cereals, reduces their yield, and fills the grain with toxins. The main direction of modern breeding is to select wheat genotypes the most resistant to Fusarium diseases. This study uses seedlings and plants at the anthesis stage to analyze total soluble carbohydrates, total and cell-wall bound phenolics, chlorophyll content, antioxidant activity, hydrogen peroxide content, mycotoxin accumulation, visual symptoms of the disease, and Fusarium head blight index (FHBi). These results determine the resistance of three durum wheat accessions. We identify physiological or biochemical markers of durum wheat resistance to F. culmorum. Our results confirm correlations between FHBi and mycotoxin accumulation in the grain, which results in grain yield decrease. The degree of spike infection (FHBi) may indicate accumulation mainly of deoxynivalenol and nivalenol in the grain. High catalase activity in the infected leaves could be considered a biochemical marker of durum sensitivity to this fungus. These findings allowed us to formulate a strategy for rapid evaluation of the disease severity and the selection of plants with higher level, or resistance to F. culmorum infection.

Molecular Boronic Acid-Based Saccharide Sensors

Boronic acids can reversibly bind diols, a molecular feature that is ubiquitous within saccharides, leading to their use in the design and implementation of sensors for numerous saccharide species. There is a growing understanding of the importance of saccharides in many biological processes and systems; while saccharide or carbohydrate sensing in medicine is most often associated with detection of glucose in diabetes patients, saccharides have proven to be relevant in a range of disease states. Herein the relevance of carbohydrate sensing for biomedical applications is explored, and this review seeks to outline how the complexity of saccharides presents a challenge for the development of selective sensors and describes efforts that have been made to understand the underpinning fluorescence and binding mechanisms of these systems, before outlining examples of how researchers have used this knowledge to develop ever more selective receptors.