**1. Endophyte Overview:**
– Endophytes were first described in 1809 by Johann Heinrich Friedrich Link.
– Victor Galippe discovered bacteria in plant tissues in 1887.
– Endophytic virome was reported by Das et al. in 2019.
– Initially thought to be plant parasitic fungi, endophytes are now known for mutualistic relationships with bacteria and fungi.
– Endophytes are transmitted vertically (parent to offspring) or horizontally (among individuals).
– Fungal hyphae penetrate embryos in host seeds for vertical transmission.
– Endophytes benefit host plants by preventing pathogens, increasing growth, and enhancing hardiness.
**2. Diversity and Classification of Endophytes:**
– Endophytic species are diverse, with many belonging to Basidiomycota and Ascomycota phyla.
– Arbuscular mycorrhizal fungi and bacterial endophytes belong to various taxa.
– Nearly every land plant hosts one or more endophytic organisms.
– Endophytes can be classified as systemic or non-systemic based on genetics and biology.
– Systemic endophytes live within plant tissues without causing harm, while non-systemic endophytes can vary and become pathogenic.
**3. Applications and Benefits of Endophytes:**
– Endophytes have potential applications in agriculture, biofuel production, phytoremediation, and drug discovery.
– They can increase crop yields, provide resistance to pests, reduce pesticide use, and enhance phytoremediation processes.
– Endophytes produce secondary metabolites with various medicinal properties useful in drug discovery.
– They enhance plant growth, improve resilience to stressors, and protect plants from herbivory and invasive insects.
– Endophytic microbes can also act as biofertilizers, improving nutrient uptake and crop resistance.
**4. Plant-Endophyte Interactions and Effects:**
– Endophyte symbiosis results in elongated root and shoot structures, increased photosynthetic capacities, and improved water relations.
– Specific biochemical mechanisms behind behavioral changes are yet to be fully understood.
– Endophytes can modulate stomatal behavior, increase water use efficiency, and promote growth through ethylene signaling.
– They contribute to disease resistance in plants and serve as a reservoir of antibacterials.
– Endophytes influence plant growth promotion, stress tolerance, and photosynthesis.
**5. Research and Future Directions:**
– Research on endophytes goes beyond isolation and metabolite documentation to understand their ecological and evolutionary importance.
– Ongoing studies explore the genetic basis of plant-endophytic bacteria interactions and the diversity and functional roles of fungal endophytes.
– Future research areas include exploring the evolutionary ecology of fungal endophytes, bacterial endophytes’ role in disease resistance, and the chemical ecology and secondary metabolites of endophytic fungi.
– Understanding the system of endophyte governance and the impact of environmental conditions on plant-endophyte relationships are areas for further investigation.
An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life cycle without causing apparent disease. Endophytes are ubiquitous and have been found in all species of plants studied to date; however, most of the endophyte/plant relationships are not well understood. Some endophytes may enhance host growth and nutrient acquisition and improve the plant's ability to tolerate abiotic stresses, such as drought, and decrease biotic stresses by enhancing plant resistance to insects, pathogens and herbivores. Although endophytic bacteria and fungi are frequently studied, endophytic archaea are increasingly being considered for their role in plant growth promotion as part of the core microbiome of a plant.
