Endophytic Fungi Are Multifunctional Biosynthesizers 45The endophytic term is always difficult to be classified as special species
and it is bears a close relationship to the term pathogen. Other scientists make
a compromise between latent infection and endophyte colonization by fungi
and proved that, they are completely different (Shearer, 2002). Too, many
scientists found that, endophytic fungi are mutualistic and asymptomatic,
whereas infectious fungi cannot be mutualistic but they are parasitic.
Moreover, the high attention that has been paid to endophytes of grass which
gives rise to the idea that, all endophytes must be mutualists (Stanley, 2002).
Also, now there is a great idea that mutualism in the fungal species may be
termed to those which are transmitted by seeds due to transmission will
increase as a host survival.
The endophytes correlated with grasses paid more attention because they
proved to produce physiologically active alkaloids that make their host toxic to
insect herbivores and mammals (Cheplick and Clay, 1988). As well,
endophytes in other plant hosts and in the grasses have been demonstrated to
promote plant growth, increase nitrogen uptake in nitrogen deficit-soils,
increase stress tolerance and reduce infection by nematodes (Bultman and
Murphy, 2000). Many of studies are available on secondary metabolite
production by endophytes (Petrini et al., 1992). Endophytic fungi produce
biologically active compounds containing many of paxilline, alkaloids,
tertaenone steroids and loliterms, proved plant growth factors and antibiotics
production. Therefore, endophytes are being identified as a group of
microorganisms that could produce secondary metabolites for agricultural and
biotechnological use (Thalavaipandian et al., 2011).
4. ECOLOGICAL ROLE OF ENDOPHYTES
Biology of endophytes is having a lot of work in research with multitude
of objectives that can be broadly classified in two classes: plant microbe
symbiosis and bioprospecting as shown in Figure 1. The bioprospecting aspect
of endophytes has been widely studies (Aly et al., 2011; Porras-Alfaro and
Bayman, 2011 and Strobel, 2015). While, the plant microbe symbiosis aspects
at molecular level has been badly understood, plant microbe interaction are
found everywhere in nature (Redman et al., 2002; Kuldau and Bacon 2008 and
Mitter et al., 2013). Actually, every plant is a complex community and this is
related to its connection in various heterospecific associations (Kiers and
Denison 2008 and Rodriguez et al., 2009). Ecophysiology like growth rate,
resistance to biotic and abiotic stress conditions, plant nutrition as well as