Plant-Associated Microorganisms as a Potent Bio-Factory of Active Molecules against Multiresistant Pathogens

Abstract

Antibiotic-resistant pathogens are a public health threat that has rapidly spread over decades due to continuous and uncontrolled administration of antimicrobial medicines, becoming an ever-increasing worldwide concern. Since the past decade, no significant innovations have been made, so the search for new compounds that face multidrug-resistant pathogens is critically important. Plant-symbiont microorganisms are capable of producing a variety of bioactive natural products, making it possible to treat several infectious diseases. Biotechnological processes using microorganisms have been increasing in recent years since the discovery of Paclitaxel, an important antimitotic produced by the endophyte Taxomyces andreanae. It was isolated for the first time from the native tree of Pacific Taxus brevifolia. Several studies have demonstrated the isolation and characterization of promising and potent substances capable of inhibiting these pathogens. In addition, both rhizospheric and endophytic communities represent an unexplored reserve of unique chemical structures for drug development. This chapter focuses on the potential of plant-derived microorganisms as a source of bioactive substances and the perspectives for further studies and their application.

Bioactive Compounds Produced by Endophytic Microorganisms Associated with Bryophytes—The “Bryendophytes”

“…The rhizosphere, a term introduced in 1904 by Lorenz Hiltner, an agronomist and plant physiologist, describes the interface between the plant root system and the soil inhabited by a versatile microbial community. Presently, this term has evolved, and the rhizosphere has been divided into three neighboring zones: the endo-rhizosphere, where microorganisms occupy free space between plant cells; the rhizoplane, localized adjacent to the root epidermal cells; and the ecto-rhizosphere, which surrounds the rhizoplane and extends into the surrounding soil, colonized by free-living or non-symbiotic microorganisms [ 15 ]. Since a diverse microbial population occupies the rhizosphere, the isolation of endophytes, which are located in the endo-rhizosphere, must include appropriate measures to eliminate possible microbial contamination originating from the rhizoplane and ecto-rhizosphere.…”