In many African countries, the Bayoud is a common disease spread involving the fungus Fusarium oxusporum f. sp. albedinis (Foa). The induction of plant natural defenses through the use of seaweed polysaccharides to help plants against pathogens is currently a biological and ecological approach that is gaining more and more importance. In the present study, we used alginate, a natural polysaccharide extracted from a brown algae Bifurcaria bifurcata, to activate date palm defenses, which involve phenylalanine ammonia-lyase (PAL), a key enzyme of phenylpropanoid metabolism. The results obtained showed that at low concentration (1 g·L⁻¹), alginate stimulated PAL activity in date palm roots 5 times more compared to the negative control (water-treated) after 24 h following treatment and 2.5 times more compared to the laminarin used as a positive stimulator of plant natural defenses (positive control of induction). Using qRT-PCR, the expression of a selection of genes involved in three different levels of defense mechanisms known to be involved in response to biotic stresses were investigated. The results showed that, generally, the PAL gene tested and the genes encoding enzymes involved in early oxidative events (SOD and LOX) were overexpressed in the alginate-treated plants compared to their levels in the positive and negative controls. POD and PR protein genes selected encoding β-(1,3)-glucanases and chitinases in this study did not show any significant difference between treatments; suggesting that other genes encoding POD and PR proteins that were not selected may be involved. After 17 weeks following the inoculation of the plants with the pathogen Foa, treatment with alginate reduced the mortality rate by up to 80% compared to the rate in control plants (non-elicited) and plants pretreated with laminarin, which agrees with the induction of defense gene expression and the stimulation of natural defenses in date palm with alginate after 24 h. These results open promising prospects for the use of alginate in agriculture as an inducer that triggers immunity of plants against telluric pathogens in general and of date palm against Fusarium oxysporum f. sp. albedinis in particular.

This study presents the first molecular characterization of arbuscular mycorrhizal fungi (AMF) isolated from single-spore cultures in Morocco, specifically from the rhizosphere of date palm (Phoenix dactylifera L.) in the Figuig oasis. Nine indigenous AMF isolates were successfully established and identified through an integrative approach combining spore morphology with ribosomal DNA region sequencing (SSU–ITS–LSU). Morphological and phylogenetic analyses revealed that the isolates belonged mainly to the genera Rhizophagus and Glomus. These results provide new insights into AMF diversity in arid Moroccan ecosystems and establish a reference collection of indigenous isolates with potential applications. In particular, they open opportunities for developing bio-inoculants that can improve date palm growth, enhance resilience to environmental stresses, and contribute to sustainable agriculture and soil restoration in oasis systems.

NAC (NAM (no apical meristem)–ATAF (Arabidopsis transcription activation factor)–CUC (cup-shaped cotyledons)) are among the largest transcription factor families in plants, involved in a plethora of physiological mechanisms. This study focused on four NAC genes previously identified in bread wheat as specifically grain-expressed which could be considered as candidate genes for yield improvement under climate changes. Using in silico analyses, the Triticum aestivum “Grain-NAC” (TaGNAC) orthologs in 14 cereal species were identified. A conserved protein motif was identified only in Triticeae. The expression of TaGNAC and einkorn TmGNAC was studied in response to moderate heat stress during grain development and showed a similar expression pattern that is accelerated during cell division stages under heat stress. A conserved structure was found in the promoter of the Triticeae GNAC orthologs, which is absent in the other Poaceae species. A specific model of promoter structure in Triticeae was proposed, based on the presence of key cis-elements involved in the regulation of seed development, hormonal regulation and response to biotic and abiotic stresses. In conclusion, GNAC genes could play a central role in the regulation of grain development in the Triticeae tribe, particularly in the accumulation of storage proteins, as well as in response to heat stress and could be used as candidate genes for breeding.