Endophytic Fungi Are Multifunctional Biosynthesizers 41microorganisms. The importance of endophytes remained hidden until 1975,
when Bacon et al., (1975) proved that, cattle toxic syndrome caused by an
endophyte of pasture grasses.
The most important group of eukaryotic microorganisms is fungi. The
structure of fungi is branching colorless hypha which extends through the
substrate where the fungus grows (Madigan et al., 2008) then; a vast number
of the hyphae of each fungus are twisted to form a tangled web named
mycelium. They have been isolated from dust, sand, soil, fresh and sea water,
marine sediment, vertebrates, marine invertebrates and tissues of terrestrial
and marine plants. They play important roles in nature, biotechnology,
agriculture and with many living organisms. Endophytic fungi research has a
long history and its diversity among plant is large. Each plant has been
colonized by one or more endophytes (Verma et al., 2007 and Kharwar et al.,
2008). Lately, endophytes are discovered to be a source of bioactive
antimicrobial natural products and secondary metabolites. Thus, endophytes
received attention in the last 20 years when the research discovered that, they
protect against pest pathogens and insect.
1. DEFINITION OF ENDOPHYTES
The endophytic word means “in the plant” (endon Gr. = within, phyton =
plant). The utilization of this term is as wide as its exacting definition and
range of potential hosts and inhabitants, e.g. fungi (Stone et al., 2000), bacteria
(Kobayashi and Palumbo, 2000), algae (Peters, 1991), insects in plants (Feller,
1995) and plants (Marler et al., 1999). This means that, any organ of the host
can be colonized. The endophytic term is also used for parasitic endophytic
plants (Marler et al., 1999), fungi (Sieber, 2002 and Schulz and Boyle, 2005),
pathogenic endophytic algae (Bouarab et al., 1999) and mutualistic endophytic
bacteria (Adhikari et al., 2001 and Bai et al., 2002). In addition, the endophyte
was named for the first time in 1866 by de Bary, to illustrate the fungi that
found in the internal tissues of stems and leaves (Wilson, 1995). From this
time this identification has been modified. Two widely accepted definitions
have been followed:
1) Endophytes colonize symptomless the internal tissues of their living
host, and after a period of times they may or may not cause diseases
(Petrini, 1991).