40 Khaled A. Selim, Mohamed M. S. Nagia and Dina E. El. Ghwas
constituents that can be used in the growth or defense mechanisms.
Fungal endophytes have attracted a great interest to microbiologists,
chemists and ecologists as a treasure of biological resource, because they
play diverse indispensable roles in the ecosystem for stress tolerance,
eco-adaptation, and promoting growth and development. Recently,
endophytic fungi have drawn a particular attention, due to their
considerable biodiversity, unparalleled metabolic pathways and unique
habitats. Therefore, they were considered as an unusual source of novel
secondary metabolites, exhibiting a variety of biological activity, which
are in use in modern agriculture, pharmaceutical and biotechnological
industry. In the last two decades, the extensive discovery of endophytic
secondary metabolites reflected the tremendous chemical diversity of
different natural compounds classes with incredible bioactivity, but still
the chemistry of endophytes needs to be comprehensively studied. On the
other hand, the search for alternative sources of fuels is becoming
increasingly important and biodiesel has been shown to be one of the
most promising alternatives. Fungal endophytes have been reported to
produce volatile low molecular mass hydrocarbons such as alcohols,
alkenes and trepenoidal mycodisel. In this review, we will focus on
characterization and diversity of endophytic fungi, with highlighting their
ecological role in nature. Besides, we will emphasis on the variety of
chemical classes and the wide spectrum biological functions of
endophytic metabolites as well as their potential as an energy source for
biofuel production.Keywords: endophytic fungi, ecological role, biofuel and hydrocarbon
production, chemical diversity, secondary metabolites, pharmaceutical
applications
INTRODUCTION
Almost all plants studied to date in the natural ecosystems are infected by
fungi and/or bacteria, some with no visible effect on their host plant in
phenomena called endophytes and others infect their hosts and significantly
impact their capacity and survival. Endophytic microorganisms are a group of
microorganisms linked with different vascular tissue of some aquatic and
terrestrial plants (Stone et al., 2000). Many groups of mycoplasma, bacteria,
actinomycetes and fungi are proved to be endophytes. Endophytic
microorganisms are invisible in plant tissue, but they have important
modulations for biodiversity, natural communities and agriculture.
Furthermore, endophytes are superb system for studying associations between