## 2 Endophytes-Current State of the Art
### Possibilities of Using Endophytes in Agriculture-Bioproducts and Strains Used in Biofertilizers
It is important to remember that the efficacy of bioproducts is highly dependent on a number of factors, such as weather conditions, soil moisture, and storage, which can affect the germination rate of conidia in fungal-based bioproducts [170]. The form of the preparation also has a great influence on its performance [148]. Microbial endophytes are found in every plant species known to date. Within the host plant the entire microbial community lives non-invasively in active internal tissues, causing no harm to the plant [6]. Endophytes interact with the host plant through metabolic communication, which enables them to generate signaling molecules. It is noted that plant endophyte communities are structurally and functionally heterogeneous for many reasons. There are various factors such as host plant, growth stage, plant organ, environmental factors, soil and management practices and the presence of plant pathogens that are responsible for the distribution of endophytes. Key research areas include the study of phytobiome components, interactions (plants, animals, other microorganisms), dynamics and functions. Also relevant in the application of endophytes as components of bioproducts is the generation of integrated system models for the analysis and prediction of the phytobiome. Most significant, however, is the development of practical crop management strategies based on the phytobiome and the establishment of global collaboration platforms for open communication between breeders, researchers, industry, agricultural advisors and consumers [6]. Currently the most important fact for agricultural producers is to be able to manage phytobiomes rather than individual components of the phytobiomes [26,176]. This paradigm shift in agriculture and ecosystem ecology could result in a solution to potential risks associated with environmental issues:  
- Increased resilience of our cropping systems to water and nutrients  
- limitation and heat stress;  
- Increased resistance to the continued emergence of new pests and pathogens;  
- Reduced yield losses due to pathogens and pests through the management of  
- practices other than pesticides as the primary means of protection;  
- Full integration of biological substances into site-specific crop management (precision agriculture);  
- Effective rehabilitation of marginal, degraded and depleted land  
- worldwide;  
- Increased possibilities to identify crops suitable for biomass, including  
- shifting cultivation systems due to climate change and data-driven  
- selection of crop species for a given location;  
- Reduced negative impact of crop production on the environment;  
- Increased safety, quality and nutritional value of our food supply;  
- Reduced reliance on external inputs to maintain crop productivity;  
- Increased capacity for effective crop management to support long-term soil and ecosystem health;  
- Adaptive, data-driven on-farm phytobiomes management systems for optim-al productivity;  
- Increased profitability of sustainable food, feed and fiber production to enable farmers to meet demand [177]. Regulation and Commercialization of Use of Endophyte-Plant Symbiosis  
Today, countries with modern agriculture have numerous rules and regulations. Their purpose is to reduce the use of chemicals and limit the side effects of their use. In 2009,plant protection acts were adopted in the European Union (EU). They are designed to protect human health and protect the environment from the risks associated with the use of pesticides. EU regulations apply in all member states and override national laws. Although uniform EU criteria guide the registration of plant protection products, the decision to place a product on the market is made for each member state separately [178]. The accession of individual countries to the EU and compliance with EU requirements is closely linked to a decline in the number of chemical plant protection products approved for marketing.