Alkaloids derived from plants are among the most significant classes of specialized metabolites due to their wide range of applications in pharmaceutical, nutraceutical and industrial sectors. However, the natural accumulation of these compounds is often limited by environmental factors, metabolic bottlenecks, and the inherent trade-off between plant growth and secondary metabolism. Recently, biostimulants have emerged as a sustainable tool to improve alkaloid production because they reprogram plant metabolic networks rather than acting only as nutrient supplements. The review critically synthesizes current knowledge on molecular mechanisms involved in the modulation of alkaloid biosynthesis in medicinal plants by major classes of biostimulants, including seaweed extracts, humic and fulvic substances, microbial biostimulants and protein hydrolysates. Special emphasis is given to the role of specific bioactive components, such as laminarin, fucoidan, alginates, humic fractions, signaling peptides, siderophores, and phytohormones-like compounds, in triggering jasmonic acid-, salicylic acid-, and MAPK-mediated signaling pathways that modulate the expression of key biosynthetic enzymes and transcription factors involved in the regulation of specialized metabolism. Furthermore, the review covers carbon-nitrogen partitioning, growth-defense optimization, timing of application, delivery methods, and interactions with abiotic stresses, all of which influence biostimulant efficacy. Current limitations such as formulation variability, inadequate mechanistic insight, poor multi-omics integration and limited field validation are critically discussed. Finally, future perspectives include the integration of transcriptomics, proteomics, metabolomics, genome editing, synthetic biology, artificial intelligence-assisted metabolic modeling and precision agriculture for the identification of regulatory hubs and development of next generation component biostimulants. These advances are expected to enable predictable, sustainable and commercially scalable production of high-value alkaloids and to improve medicinal plant resilience to changing environmental conditions. Graphical abstract

Rice, wheat, and maize cereals are the major foundation of global food security. However, climate change makes it more challenging to achieve high crop yield, the challenge occurs due to improper management of cereal diseases and pests, and limitations of traditional breeding processes. This study aimed to update the process, limitations, and prospects of molecular tools for cereal breeding, and to explore the significance of marker-assisted selection, marker-assisted backcrossing, gene pyramiding, genomic selection, and modern breeding for improving yield, stress tolerance, and grain quality of cereals. Based on recent studies, we have explored the advances and applications of high-throughput genotyping platforms like the single nucleotide polymorphism (SNP) array and genotyping by sequencing technology in cereals. In this study, we found several limitations, such as a low number of studies with large amounts of data, genotype-environment interactions, lack of study findings at the field level, cost implications, and integration of complex multi-omics data. This study further reveals that many crucial agronomic traits are polygenic in their mode of inheritance, and the hidden genetic links make selection weak and uncertain. However, the application of molecular tools such as CRISPR/Cas genome editing, speed breeding, pan-genomics, artificial intelligence, and high-throughput phenomics provides sustainable solutions to these challenges in cereal improvement. The application of these modern breeding tools, combined with microbiome-assisted breeding and agricultural technologies in precision cereal breeding, opens new opportunities for enhancing yield and climate-smart, sustainable cereal production for global food and nutrition security.

Drought stress represents the most significant threat to global forage productivity, necessitating a robust understanding of adaptive belowground mechanisms. This paper highlights the critical advancements in root system architecture (RSA) and root vascular architecture that underpin resilience in forages. Under water-limited conditions, forages exhibit substantial morphological plasticity, characterized by a 20-40% increase in primary root elongation and a strategic rise in root-to-shoot ratios to prioritize deep-layer moisture acquisition. Anatomically, they optimize hydraulic safety through a 10-40% reduction in xylem vessel diameter, which enhances embolism resistance by 20-35% despite a minor decline in hydraulic conductivity. Metabolic efficiency is further bolstered by the development of root cortical aerenchyma, which reduces cortical area by 30-50% and lowers maintenance respiration costs by up to 60%. Parallel to these metabolic shifts, the reinforcement of endodermal barriers specifically 1.5-2 times thickening of the Casparian strip and a 1.5-2.2 times elongation of root hairs maximizes water-use efficiency and soil-root contact. The review further examines the physiological drivers of these changes, indicating that moderate ABA accumulation can contribute to the maintenance or stimulation of primary root elongation under stress, with reported increases of 20–40% depending on genotype and environmental conditions. By integrating these multi-scale traits with high-throughput phenotyping and symbiotic interactions, this paper provides a framework for breeding climate-resilient forage ideotypes essential for sustaining livestock systems and global soil carbon stocks.