The Effect of Microbiome and Algae on Forest Seed Germination: Functional Mechanisms and Biotechnological Perspectives

Forests are fragile ecosystems that are imperiled by various factors associated with human activity and climate change. They necessitate new and effective solutions for their natural and efficient regeneration. The germination of forest seeds is essential for ecosystem restoration and the safeguarding of biodiversity. This process is affected by various biotic and abiotic elements, such as the quality of the current soil microbiome and algae. These organisms are crucial in facilitating forest regeneration by enhancing seed physiology, augmenting stress resilience, improving nutrient acquisition, stimulating phytohormone production, and protecting against diseases. The soil microbial-algal consortium stimulates seed hydration and metabolic activation through external bioactive signals and availability of amino acids and polysaccharides, the specifics of which remain inadequately clarified. Recent studies suggest that the functional actions of the soil microbiome and algae may be a new way to increase forest seed germination in general, especially for preserving threatened and endangered species. In order to restore forest health, this review identifies the function mechanisms through which the microbiome and algae complex impacts seed germination, indicates the limitations of past studies to improve or conserve seed germination, and discusses more sustainable advanced biotechnological approaches that integrate the benefits of the microbiome and algae complex, such as bioformulations and seed coatings containing microbial and algal extracts.