Background: Plant fungal pathogens cause substantial economic losses through crop yield reduction and post-harvest storage losses. The utilization of biocontrol agents presents a sustainable strategy to manage plant diseases, reducing the reliance on hazardous chemical. Recently, Pichia kudriavzevii has emerged as a promising biocontrol agent because of its capacity to inhibit fungal growth, offering a potential solution for plant disease management. Results: Two novel Pichia kudriavzevii strains, Pk_EgyACGEB_O1 and Pk_EgyACGEB_O2, were isolated from olive brine samples. The microscopic characterization of the strains revealed similar structures. However, there were noticeable differences in their visual morphology. Based on their internal transcribed spacer (ITS) DNA sequences, Pk_EgyACGEB_O1 and Pk_EgyACGEB_O2 strains assigned by GenBank IDs MZ507552.1 and MZ507554.1 shared high sequence similarity (~ 99.8% and 99.5%) with P. kudriavzevii, respectively. Both strains were evaluated in vitro against plant pathogenic fungi. The strains revealed the ability to consistently inhibit fungal growth, with Pk_EgyACGEB_O2 showing higher effectiveness. In addition, both P. kudriavzevii strains effectively controlled grey mold disease caused by B. cinerea in golden delicious apples, suggesting their potential as sustainable and eco-friendly biocontrol agents for post-harvest diseases. Based on a comprehensive bioinformatics pipeline, candidate-secreted proteins responsible for the potent antifungal activity of P. kudriavzevii were identified. A total of 59 proteins were identified as common among the P. kudriavzevii CBS573, SD108, and SD129 strains. Approximately 23% of the secreted proteins in the P. kudriavzevii predicted secretome are hydrolases with various activities, including proteases, lipases, glycosidases, phosphatases, esterases, carboxypeptidases, or peptidases. In addition, a set of cell-wall-related proteins was identified, which might enhance the biocontrol activity of P. kudriavzevii by preserving the structure and integrity of the cell wall. A papain inhibitor was also identified and could potentially offer a supplementary defense against plant pathogens. Conclusion: Our results revealed the biocontrol capabilities of P. kudriavzevii against plant pathogenic fungi. The research focused on screening novel strains for their ability to inhibit the growth of common pathogens, both in vitro and in vivo. This study shed light on how P. kudriavzevii interacts with fungal pathogens. The findings can help develop effective strategies for managing plant diseases.

Understanding the role of cysteine-rich receptor-like kinases (CRKs) in plant defense mechanisms is crucial for enhancing wheat resistance to leaf rust fungus infection. Here, we identified and verified 164 members of the CRK gene family using the Triticum aestivum reference version 2 collected from the international wheat genome sequencing consortium (IWGSC). The proteins exhibited characteristic features of CRKs, including the presence of signal peptides, cysteine-rich/stress antifungal/DUF26 domains, transmembrane domains, and Pkinase domains. Phylogenetic analysis revealed extensive diversification within the wheat CRK gene family, indicating the development of distinct specific functional roles to wheat plants. When studying the expression of the CRK gene family in near-isogenic lines (NILs) carrying Lr57- and Lr14a-resistant genes, Puccinia triticina, the causal agent of leaf rust fungus, triggered temporal gene expression dynamics. The upregulation of specific CRK genes in the resistant interaction indicated their potential role in enhancing wheat resistance to leaf rust, while contrasting gene expression patterns in the susceptible interaction highlighted potential susceptibility associated CRK genes. The study uncovered certain CRK genes that exhibited expression upregulation upon leaf rust infection and the Lr14a-resistant gene. The findings suggest that targeting CRKs may present a promising strategy for improving wheat resistance to rust diseases.

Wheat leaf rust, caused by Puccinia triticina, poses a growing threat to global wheat production, necessitating alternative strategies for effective disease management. This study investigated the potential of gamma-aminobutyric acid (GABA) to enhance resistance to leaf rust in two wheat cultivars: the susceptible Morocco and moderately resistant Sakha 94 cultivar. Our findings revealed that GABA significantly improved resistance in both cultivars to P. triticina, particularly in Morocco, by mitigating disease severity and reducing pustule density and size while extending both incubation and latent periods. This study assessed the effectiveness of two GABA application methods: plants received 1 mM GABA treatment, as a foliar spray, twenty-four hours prior to infection (pre-GABA), and plants received 1 mM GABA treatment both 24 h before and after infection (pre-/post-GABA), with the latter yielding significantly better results in reducing infection severity and improving plant resilience. Additionally, GABA application influenced stomatal behavior, promoting closure that may enhance resilience against leaf rust. GABA application on plants also modulated the production of reactive oxygen species (ROS). This led to a stronger oxidative burst in both susceptible and moderately resistant cultivars. GABA increased O₂^●− levels in guard cells and surrounding stomata, enhancing stomatal closure and the hypersensitive response. GABA enhanced the accumulation of soluble phenols and increased the activity of key antioxidant enzymes, catalase (CAT) and peroxidase (POX), which are vital for managing oxidative stress. To the best of our knowledge, this investigation represents the first report into the impact of GABA on wheat leaf rust disease.

Background: Basil (Ocimum sp.) exhibits significant morphological and genetic diversity. This variation provides an opportunity to identify novel traits that can be used in breeding programs to improve the productivity, quality, and disease resistance of basil plants. The integration of morphological and genetic data for basil varieties can improve our understanding of biodiversity, conservation, and breeding programs. Results: In 2019, we conducted a comprehensive investigation on 25 basil landraces collected from 12 Egyptian governorates to explore their morphological and genetic diversity. Morphological characterization revealed variability in plant vigor, flower color, cyme shape, and leaf shape, indicating distinct growth patterns and potential for specific applications. Productivity and biochemical evaluation demonstrated significant variation in yield and oil distillation, identifying top-performing landraces L5, L11, and L24 that can be used in breeding programs to optimize performance and reduce environmental impact. The genetic diversity of the landraces was investigated using 11 SCoT primers revealed high levels of genetic diversity among landraces, with a wide range of polymorphism variation. The phylogenetic analysis identified two distinct clades, providing valuable insights into genetic diversity and relationships between different landraces. An interesting observation was made in the study, whereby L6 and L13, collected from Fayoum and Port-Said, respectively, were found to be the closest landraces. Following closely were L7 and L14, which were also collected from the same governorates. These findings have significant implications for the conservation of these landraces, as they may have evolved from similar species. Conclusions: This study sheds light on the genetic diversity and relationships among 25 Egyptian basil landraces. Using SCoT markers, a high level of polymorphism was detected, indicating significant variation in the genetic makeup of the landraces. The study also revealed interesting observations regarding the relationships among the landraces, with some landraces appearing to have evolved from similar species. The phylogenetic analysis provided insights into the genetic relationships among the landraces, which can guide conservation efforts and breeding programs. Overall, this study provides valuable information for researchers, breeders, and farmers involved in the conservation, breeding, and utilization of basil genetic resources in Egypt.

Cadmium (Cd) toxicity is a serious threat to agronomic crop productivity worldwide. It raises severe concerns about the food and nutrient security required to meet the demands of a rapidly growing population, while also creating grave challenges for agriculture. Silicon (Si) and strigolecton (SL) are reported to impart multiple benefits to plants exposed to abiotic stress. Therefore, the current experiment was performed to evaluate the effects of silicon (4.0 mM) and strigolecton (20 µM) on the amelioration of cadmium (25 mg kg⁻¹ soil) stress in maize seedlings via intervention in morphological attributes, photosynthetic pigments, enzymatic antioxidant mechanisms, and osmolyte accumulation. The results indicated that morphological attributes and photosynthetic pigments were significantly reduced in Cd-exposed seedlings. However, foliar application of Si and SL, both individually and in combination, significantly improved the growth attributes and photosynthetic pigments of maize seedlings under both control and Cd-stress conditions. Exposure of maize seedlings to Cd stress increased H₂O₂ levels, malondialdehyde content, and electrolyte leakage and reduced cell membrane stability. These effects were significantly negated by Si and SL supplementation, both individually and in combination. Moreover, enzymatic antioxidants, including catalase, superoxide dismutase, peroxidase, and ascorbate peroxidase, were activated after Cd stress, but their activity was further increased with foliar application of Si or SL. In Cd-contaminated seedlings, the combined application of Si and SL enhanced soluble proline, sugars, and total phenolic contents as compared to the control treatment. Furthermore, Si and SL applications increased Si accumulation in Cd-exposed seedlings and decreased Cd uptake. It was concluded that the combined application of Si and SL improved Cd tolerance in maize seedlings by modulating morpho-physiological attributes, photosynthetic pigments, and osmolytes accumulation, and by supporting the antioxidant defense system. The findings of this study suggest that Si and SL could be safe and effective strategies for reducing Cd toxicity in maize seedlings.

Background/Objectives: The phytosulfokine receptor (PSKR) gene family plays a crucial role in regulating plant growth, development, and stress response. Here, the PSKR gene family was characterized in Triticum aestivum L. The study aimed to bridge knowledge gaps and clarify the functional roles of TaPSKRs to create a solid foundation for examining the structure, functions, and regulatory aspects. Methods: The investigation involved genome-wide identification of PSKRs through collection and chromosomal assignment, followed by phylogenetic analysis and gene expression profiling. Additionally, interactions with their interactors were stimulated and analyzed to elucidate their function. Results: The wide-genome inspection of all TaPSKRs led to 25 genes with various homeologs, resulting in 57 TaPSKR members distributed among the A, B, and D subgenomes. Investigating the expression of 61 TaPSKR cDNAs in RNA-seq datasets generated from different growth stages at 14, 21, and 60 days old and diverse tissues such as leaves, shoots, and roots provided further insight into their functional purposes. The expression profile of the TaPSKRs resulted in three key clusters. Gene cluster 1 (GC 1) is partially associated with root growth, suggesting that specific TaPSKRs control root development. The GC 2 cluster targeted genes that show high levels of expression in all tested leaf growth stages and the early developmental stage of the shoots and roots. Furthermore, the GC 3 cluster was composed of genes that are constantly expressed, highlighting their crucial role in regulating various processes during the entire life cycle of wheat. Molecular docking simulations showed that phytosulfokine type α (PSK-α) interacted with all TaPSKRs and had a strong binding affinity with certain TaPSKR proteins, encompassing TaPSKR1A, TaPSKR3B, and TaPSKR13A, that support their involvement in PSK signaling pathways. The crucial arbitration of the affinity may depend on interactions between wheat PSK-α and PSKRs, especially in the LRR domain region. Conclusions: These discoveries deepened our knowledge of the role of the TaPSKR gene family in wheat growth and development, opening up possibilities for further studies to enhance wheat durability and yield via focused innovation approaches.