**6. Conclusions**

In this review, we summarized the results obtained so far with the artificial introduction of EF in tomato and the subsequent beneficial effects that were observed. The main benefits to tomato plants are attributable to the biocontrol of several insect pests and plant pathogens, as well as their ability to improve plant performance. A focus on naturally occurring, constitutive EF of tomato was also undertaken, aimed at emphasizing their possible role in the selection of new beneficial strains for future use in tomato crop improvement. Moreover, an overview was conducted on the methods of introduction and detection of EF in tomato, providing a clear synthesis of the techniques used, that could be a practical guide to other researchers approaching this interesting field of research. The potential applications of endophytic fungi in horticultural production provide many advantages to the agroecosystem in terms of reducing chemical use and establishing a biological equilibrium necessary for the establishment of sustainable agriculture.

**Author Contributions:** Conceptualization, M.S., M.R., and S.L.W.; literature investigation M.S., M.R., G.d., and L.G.; writing—original draft preparation, M.S. and M.R.; writing—review and editing, S.L.W., project administration, S.L.W.; funding acquisition, S.L.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the following projects: European Union Horizon 2020 Research and Innovation Program, ECOSTACK (grant agreement no. 773554); fundings and a Ph.D. bursary to M.R. in PRIN 2017 [grant number PROSPECT 2017JLN833].

**Acknowledgments:** Thanks are due to Nadia Lombardi of the University of Naples, Federico II, for her editorial assistance.

**Conflicts of Interest:** The authors declare no conflict of interest.
