Search Results (3)

Manganese (Mn) deficiency is a major factor underlying brittle leaf disease in date palm, yet its root-centered mechanisms under field conditions remain poorly understood. Nine mature palms (three per health category: healthy, asymptomatic Mn-deficient, and BLD-affected) were assessed for soil chemistry (pH, salinity), root Mn concentration and hydraulics, canopy pigments and chlorophyll fluorescence (F_v/F_m), as well as metabolic responses. Elevated soil pH and variable salinity significantly constrained root Mn uptake and water conductance, leading to a ~60% decline in root Mn, a 20% reduction in root water content, an 80% loss of chlorophyll, and a 26% decrease in F_v/F_m. These changes induced strong metabolic reprogramming, including a twofold rise in glucose, increased protein content, and a tenfold enhancement in peroxidase activity. Asymptomatic palms already displayed early declines in pigments and fluorescence, highlighting their diagnostic value. This study demonstrates that soil-driven Mn deficiency impairs root function and cascades to canopy physiology and metabolism, offering realistic avenues for rhizosphere management and early field diagnosis in arid oases. Full article

China, the largest global producer of sweet potatoes, faces significant threats from viral diseases, particularly in Fujian Province, where sweet potatoes are the second most important food crop after rice. This study identified 11 viruses, including sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV), infecting sweet potatoes in Fujian. Sequence comparisons revealed diverse strains from various sources. Virus prevalence varied across regions, with Quanzhou, Fuzhou, and Putian severely affected, detecting 10, 9, and 7 viruses, respectively, compared to only 3 in Sanming and Longyan. In particular, sweet potato virus disease (SPVD) caused the most severe damage during the seeding stages, resulting in dwarfing and leaf deformation, while the damage was lighter during the growth period, manifesting as the yellowing and brittleness of the leaves, ultimately reducing the yield. Compound infestations predominated, with between 0 and 6 viruses infecting different sweet potato varieties. Single-virus infections were observed for sweet potato virus 2 (SPV2), sweet potato symptomless virus 1 (SPSMV-1), and sweet potato pakakuy virus (SPPV), while others, particularly SPCSV, were frequently co-infected with SPFMV, leading to SPVD development. Further analysis showed that the RNase3 expression of SPCSV was correlated with the SPVD severity in sweet potato. These findings provide insights into the epidemiology of sweet potato viruses and serve as a reference for developing targeted disease management strategies. Full article

Endophytic fungi of healthy and brittle leaf diseased (BLD) date palm trees (Phoenix dactylifera L.) represent a promising source of bioactive compounds with biomedical, industrial, and pharmaceutical applications. The fungal endophytes Penicillium citrinum isolate TDPEF34, and Geotrichum candidum isolate TDPEF20 from healthy and BLD date palm trees, respectively, proved very effective in confrontation assays against three pathogenic bacteria, including two Gram-positive bacteria Bacillus thuringiensis (Bt) and Enterococcus faecalis (Ef), and one Gram-negative bacterium Salmonella enterica (St). They also inhibited the growth of three fungi Trichoderma sp. (Ti), Fusarium sporotrichioides (Fs), Trichoderma sp. (Ts). Additionally, their volatile organic compounds (VOCs) were shown to be in part responsible for the inhibition of Ti and Ts and could account for the full inhibition of Fs. Therefore, we have explored their potential as fungal cell factories for bioactive metabolites production. Four extracts of each endophyte were prepared using different solvent polarities, ethanol (EtOH), ethyl acetate (EtOAc), hexane (Hex), and methanol (MetOH). Both endophyte species showed varying degrees of inhibition of the bacterial and fungal pathogens according to the solvent used. These results suggest a good relationship between fungal bioactivities and their produced secondary metabolites. Targeting the discovery of potential anti-diabetic, anti-hemolysis, anti-inflammatory, anti-obesity, and cytotoxic activities, endophytic extracts showed promising results. The EtOAc extract of G. candidum displayed IC₅₀ value comparable to the positive control diclofenac sodium in the anti-inflammatory assays. Antioxidant activity was evaluated using α,α-diphenyl-β-picrylhydrazyl (DPPH), β-carotene bleaching, reducing power (RP), and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonique) (ABTS) radical scavenging assays. The findings revealed strong anti-oxidant power with an IC₅₀ of 177.55 µg/mL for G. candidum EtOAc extract using DPPH assay, probably due to high polyphenol and flavonoid content in both fungal extracts. Finally, LC-HRMS (Liquid Chromatography–High Resolution Mass Spectrometry) and GC-MS (Gas Chromatography–Mass Spectrometry) analysis of G. candidum and P. citrinum extracts revealed an impressive arsenal of compounds with previously reported biological activities, partly explaining the obtained results. Finally, LC-HRMS analysis indicated the presence of new fungal metabolites that have never been reported, which represent good candidates to follow for the discovery of new bioactive molecules. Full article